Simple & Modular Wearable Lights

Build fabulous, futuristic, and adjustable wearable lights with just a few inexpensive (and deliverable) parts! Attach to to all sorts of accoutrements and swap out colors to match outfits/feelings/holidays/all the things!

Difficulty: Beginner+

Read time: 5 min

Build Time: 30 – 60 min

Cost: ~ $5

Materials

Tools

  • Safety Goggles!
  • Soldering iron and accessories*
  • Waterproof epoxy or superglue
  • Wire strippers
    • Scissors will also work just be careful to avoid cutting the wire.

*Unable to solder? Follow instructions but instead of soldering, tightly wrap and twist bare wire connections together, then wrap tightly with ​​conductive nylon fabric tape.

Setup!

  1. Turn on the soldering iron.
  2. Remove about 1/2″ (1cm) or the plastic coating on each of the female JST connectors.
  3. New to LEDs? Test ’em out!
    • Grab your coin cell and one of your LEDs.
    • With just those two pieces, explore how to make the LED light up!
    • Hint: Read the coin cell battery. How many sides does the battery have? How many legs does the LED have?

Make the first connector!

For all steps, be sure the coin cell is NOT in the battery holder.

Step 1: Solder your first resistor to the negative ( – ) hole on the coin cell battery holder.

  • With the switch facing you, use the negative hole on the left side of the holder.
  • Pro Tip: Wrap the resistor wire around the hole, getting the resistor body as close to the hole as possible. Use the soldering iron to heat the joint for about 3 seconds, then add solder to fill in the hole.

Step 2: Grab your first JST connector and solder the black wire to the other end of the resistor.

  • Pro Tip: Wrap the JST connector bare wire around the resistor leg as close to the resistor body as possible.

Step 3: Solder the red JST connector wire to the positive ( + ) hole on the battery holder.

  • With the switch facing you, use the positive hole on the left side of the holder.
  • Pro Tip: Wrap the JST connector bare wire around the hole Use the soldering iron to heat the joint for about 3 seconds, then add solder to fill in the hole.

Make the second connector!

Repeat the same process as for the first light, but using the right-side holes on the battery holder.

More details:

For all steps, be sure the coin cell is NOT in the battery holder.

Step 1: Solder your second resistor to the negative ( – ) hole on the coin cell battery holder.

  • With the switch facing you, use the negative hole on the right side of the holder.
  • Pro Tip: Wrap the resistor wire around the hole, getting the resistor body as close to the hole as possible. Use the soldering iron to heat the joint for about 3 seconds, then add solder to fill in the hole.

Step 2: Grab your first JST connector and solder the black wire to the other end of the resistor.

  • Pro Tip: Wrap the JST connector bare wire around the resistor leg as close to the resistor body as possible.

Step 3: Solder the red JST connector wire to the positive ( + ) hole on the battery holder.

  • With the switch facing you, use the positive hole on the right side of the holder.
  • Pro Tip: Wrap the JST connector bare wire around the hole Use the soldering iron to heat the joint for about 3 seconds, then add solder to fill in the hole.

Test and Secure Joints

Step 1: Trim any excess wire.

Step 2: Insert the coin cell battery into the holder and move the switch to the “ON” position.

Step 3: Insert LEDs into the JST connectors so that the longer (positive) LED leg plugs into the red wire of the JST connector.

Step 4: Check to ensure that the LEDs light up! If it does, proceed to Step 4. If not, follow the troubleshooting guidelines below.

Step 5: Remove the battery, then thoroughly cover all exposed solder joints with epoxy or super glue and let dry in a safe, out-of-the-way spot. Remember to glue the back of the battery holder!

  • Be sure to glue the connections between the JST connector and resistor. Coat the positive and negative solder holes, but DO NOT cover any other parts of the holder or it may be impossible to insert the battery or use the switch.
  • Check the dry time for your glue (mine was about 60 minutes until fully dried). Be sure to avoid bumping or getting hair on your project, as it will be hard to remove after (as a dog owner this is a constant challenge!).
  • Pro Tip: Use a fine-tipped brush or skewer to add the glue.

Troubleshooting:

  • Check the power. The battery should be inserted so that the positive side (with the writing) is facing up.
  • Double check the LEDs are inserted in the correct orientation: longer leg to positive (red) wire, shorter leg to negative (black) wire.
  • Gently wiggle your solder connections. If you notice the LED flashes on, it is likely a poor solder connection.
    • Remove the battery and add more solder to your joint.
  • Check that the solder joints are not shorting the battery holder. If you feel the battery getting warm, this is likely the culprit
    • Check that the solder is contained to the positive and negative holds ONLY. It should not be touching any other parts of the holder, especially any exposed metal.

Finish & Flaunt!

Finally, grab your attachment mechanism and, if needed, glue to the back of the battery holder and let dry (I used a magnet for mine so no glue necessary!). Insert your preferred LEDs and attach your light-up accessory to your clothes or hair for some futuristic flourish!

Going Further

  • Sew somethin’ pretty to go over the lights!
  • Aside from hair, explore different options for diffusing the LED light. Some quick, inexpensive options are ping pong balls, a dab of hot glue around the LED bulb, or white fabric.
  • More lights!! Test before doing this as the brightness of the lights will change depending on whether you connect them in series or in parallel.
  • Add a dark detecting circuit so your lights only turn on in the daytime!
    • You can harvest a dark detecting circuit from a solar path light.
    • Or search online for the circuit!

Questions? Ideas? Let me know! I’d also love to see your finished creations, so please share!

micro:bit Dog Door Opener

​Do your pets trap themselves in rooms? Do you wish you could make your home more accessible for your furry* friends?? Now you can, hooray!!

This project uses a micro:bit microcontroller to pull open a door when a (pet-friendly) switch is pushed. We’ll need a micro:bit (probably helpful), a high-torque motor, and some mechanical parts and pieces to mount the motor and connect the motor to the door.

Read Time: ~15 min

Build time: ~30-45 min

Cost: ~$60

*This project can be used as a low-cast way to improve home, workplace, or other physical space accessibility for humans, too! Yay!!

 

Materials

  • ​micro:​bit 
  • microUSB cable (3ft or more)
  • ​Binary Bots Planet Totem Spider Kit​
    • If this is your first robotics project, I’d highly recommended to use this kit and follow the tutorial as-is. If you’ve done a few projects before, feel free to make adjustments and modifications. Here are two things to keep in mind:
      • This project requires a high torque motor to pull open our door. The motor control system and high torque mini DC motor from this kit were super helpful in building this project.
      • The assorted boards, nuts, and bolts were also handy, but could be replaced with similar mechanical parts from another robotics kit or directly from a manufacturer.
  • 2 lengths of 24 gauge stranded wire, 3 – 4ft (1 – 1.3m)
  • Fishing line, 4′ (1.3m)
  • Aluminum, 2″x3″ rectangle (5 – 7cm)
  • 8 small nails
  • 6 push pins
  • Wall sticky putty

Tools

  • ​Driver kit
    • Note: the Binary Bots kit does come with an M3 driver (and it’s magnetic, wooo!!!) and a tiny screwdriver.
  • Hammer
  • Wire Strippers
  • Hot Glue Dispenser (not pictured)
  • Scissors
  • Measuring Tape
  • Pencil

Prep and Aluminum Latch Cover

​1. Measure and record the width of your door (the inside part).

2. At a 45 deg angle, measure the distance from the door latch to the wall perpendicular to the door hinges.

Note: your particular room setup is likely different than mine. The key thing to keep in mind is that torque is the lowest when it is applied perpendicular. In other words, try to attach the motor as close to perpendicular as possible. A 45 deg angle is likely the smallest angle you’ll want, larger angles will be easier for the motor to pull open the door.

3. Cut a 2″x3″ piece of aluminum (e.g. from a recycled can).

 

Build it: Door Connection Mechanism!

Materials

To build this part, you’ll need the following pieces from the Binary Bots Kit:

  • 3 100x30cm boards
  • 2 2-hole 90deg brackets
  • 4 6mm M3 bolts
  • 4 lock nuts
  • 2 8mm M3 bolts
  • 2 M3 nuts

Procedure

1. Grab one of the boards. From the left edge, measure and mark the width of the door.

2. Grab a second board. Connect the second board to the first perpendicularly to each other, so that the second board is just to the right of the door width line.

To do this, use both brackets, 4 6mm M3 bolts, and 4 lock nuts.

3. Grab the third board and connect it to the second in a straight line using the longer (8mm) M3 bolts and rectangular M3 nuts.

Set aside and move on to the next part, woo!

Build it: Pet-Friendly Switch!

​Materials

To build this part, you’ll need the following pieces from the Binary Bots Kit:

  • 2 100x30cm boards
  • 4 6mm M3 bolts
  • 4 M3 nuts
  • 2 8mm nylon standoffs

You’ll also need:

  • 2 3-4ft (1-1.3m) of stranded 24 gauge wire
    • Remove about 1in (2.5cm) of the insulation from both ends​
  • 3 push pins

Procedure

1. Grab one of your boards and attach the nylon standoffs to the left side using two (2) M3 nuts.

2. Grab the second board and use two (2) M3 bolts to secure the second board to the first via the nylon standoffs.

3. Grab one of the M3 bolts and push it through a hole on the far right end of the top board. Wrap one end of the wire around the base of the bolt. 

4. Use an M3 nut to secure the bolt in place.

5. Repeat steps 3 and 4 for the bottom board, making sure that the second bolt is directly below the first.

When you close the switch (aka push the boards together), the top and bottom bolts should press together and make full contact.

Build it: Motor Mount!

Materials

​To build this part, you’ll need the following pieces from the Binary Bots Kit:

  • 1 100×100 cm board
  • 1 Tiny Motor with 2 tiny screws (so cute and yet so powerful!)
  • 1 Motor Mount (“web launcher”)
  • 1 reel set (“web reel”)
  • 6 6mm M3 bolts
  • 6 M3 nuts

You’ll also need:

  • 6 small nails
  • 1 pushpin​
  • 4ft (1.3m) of fishing line (or equally strong line)

Procedure


1. Insert and secure the motor into the motor mount with the two tiny screws (highly recommended to use a larger screwdriver if you have one..)

2. Grab the 100x100cm board and use the 6 M3 bolts and nuts to attach the motor on the left side in (roughly) the middle.

3. Grab the reel and fishing line. Thread one end of the fishing line through the middle of the reel, then wrap around the teeth. Secure with a dab of hot glue.

4. Push the two reel pieces together (pinching the thread between the two pieces), and insert into the motor drive shaft so that the web part faces outward. Secure with a dab of hot glue on the outside.

Connect it: Electronics!

Materials

  • micro:bit
  • microUSB cable
  • Binary Bots motor driver board
  • 3 AAA batteries

Procedure

1. Grab the Motor Mount setup you just put together, and plug in the motor to the motor driver board.

Connect the red motor wire to the left header pin labeled “Motor1”. Connect the black motor wire to the right header pin labeled “Motor1”.

2. Connect the pet-friendly switch! Connect one of the switch wires to the micro:bit P0 pin, and the other to the micro:bit GND pin (doesn’t matter which switch wire goes where).

3. Insert the micro:bit into the motor driver board so that the pushbuttons are facing outwards (away from the motor driver).

4. Insert the batteries into the motor driver board. Locate the power switch and move to “off”.

Code it: Motor Control!

Navigate to the Make Code website: www.MakeCode.org and select the micro:bit option, then “New Project”. It is recommended to rename your project to help you identify what it is doing, like “DogDoorOpener”.

Some background info: 

When Pin P0 is triggered (via the switch closing), we want to turn the motor so that it pulls open the door by spooling (aka reeling in) the fishing line. We also want to unspool the fishing line so we can shut the door again. It is also helpful to have a manual way to spool and unspool the motor, as well as to cut power to the motor.. just in case!

Since we are dealing with a DC motor, when we give power to one of the motor leads and ground the other, the motor will rotate in one direction. When we switch power to the motor leads, the motor will rotate in the other direction. Cutting power to both motor leads turns off the motor.

Let’s get started!

First Code Function: Motor Triggered by Doggo Switch

1. Pull out a “when pin is pressed” (input blocks) and make sure it is set to pin P0.

2. Inside the pin P0 block, use the digital write blocks to turn on micro:bit pin P13 (set to 1) and turn off micro:bit pin P14. This turns the motor on in one direction. 

The digital write blocks are found under Advanced –> Pins. Select the appropriate pins by clicking on the down arrow.

3. Add a pause for about 7s (7000 ms), then turn the motor off by setting P13 and P14 to 0.

Note: 7 seconds worked well for my setup and my doggo’s needs, but definitely check that this is enough (slash not too much) time to adequately open your door for your needs.

4. Unspool the motor (aka rotate it in the reverse direction) by using a digital write block to turn on P14 and turn off P13. Be sure to unspool the same amount of time as you spool.

5. Optional: use the LEDs to include a countdown/count-up timer to let you know when the motor will be turned on. Also recommended to add a pause between when the switch is pressed as well as when before the motor unspools.

Second Code Function: Manual Open

1. To make a manual switch, drag out a “On Button A pressed” (input blocks).

2.  Inside this block, use the digital write blocks to turn on micro:bit pin P13 (set to 1), and turn off micro:bit pin P14 (set to 0).

3. Add a pause block for ~3s (3000 ms).

4. Turn off the motor! (by setting the digital write blocks to 0)

5. Optional: Show an icon before you turn the motor on so you know which way the motor will be turning.

For mine, I chose a rectangle outline so indicate “open door”, choose something that makes sense to you and your brain.

Third Code Function: Manual Close

1. To make a manual switch, drag out a “On Button B pressed” (input blocks).

2.  Inside this block, use the digital write blocks to turn on micro:bit pin P13 (set to 0), and turn off micro:bit pin P14 (set to 1). 

3. Add a pause block for ~3s (3000 ms). 

4. Turn off the motor! (by setting both digital write blocks to 0)

5. Optional: Show an icon before you turn the motor on so you know which way the motor will be turning.

Fourth Code Function: Turn Off Motor

1. Pull out a “On Button A+B pressed” block.

2. Use two digital write blocks to set both P13 and P14 to 0.

Install it!

1. Use some of the wall sticky putty to wrap the aluminum around the door latch.

Bend the aluminum around the latch so that the door is able to fully close, but prevents it from sticking.

2. Using your hot glue dispenser, glue the short end of the door mechanism piece to the door width, just below the latch. Glue the longer piece to the door to provide extra stability.

3. Attach the motor mount and the motor controller board to the wall. Use the push pins temporarily to hold the pieces in place, then use 6 nails to secure the motor controller, and 2 to secure the motor controller board.

4. Use the wall sticky putty to attach the switch in a place that is convenient for whoever will be triggering the door to open. Since my dog is fairly large, I installed it about 1.5ft (0.5m) up from the floor so that doggo could press the switch with his nose.

I preferred to sticky putty so I could adjust the switch and remove things as necessary, but if you want to make this permanent you can use nails or hot glue.

5. Use the pushpins to secure the switch wires to the wall and prevent them from getting disconnected.

6. Attach the fishing line between the motor reel and the door mechanism. Close the door fully, then wrap the fishing line around the door mechanism a few times so that it is taught, then secure with hot glue.

Test & Deploy! And make your home more accessible, hooray!

​Huzzah!! Ready for the testing phase! Power up the micro:bit (via the microUSB cable) and turn on the motor controller board.

Trigger the switch and check that the motor pulls open the door enough for your furry friend to escape! And also that the motor unspools so you can close the door again.

Very likely something will need to be adjusted/fixed, so check all of the buttons, make sure the system is secure to the wall and does not block anything.

Once you’ve tested your Doggo Door Opener, show it to your pet! … And maybe train them, ha. I did this by using treats on top of the switch, so that my dog accidentally triggered the switch, then he saw that door opened. It took a few tries (I also ended up giving it a command of “get the switch”), but eventually he figured it out! And now I can leave my lovely but oh-so-anxious dog home alone without worrying he will trap himself (on purpose? I have no idea).

Hooray for using tech to make our own lives and the lives of others easier and better!

Let me know if you have any questions, run into any issues, or have other ideas for this project, I’d lovelovelove to see what you make so please share your creations!

Happy making, friends!

Mini Robotic Table

What’s better than a table with wheels? A table that you can drive around! This tutorial will teach you how to build your very own Mini Robotic Table, a project that was conceived and designed by one of my students (she was 10 when we started).

We built this table because, in the words of my student:

“I wanted to build something and I thought of a table and I thought of robotics and I smooshed them together. I like woodworking and I like robotics and I wanted to do something with the both of them.

We started w/ a full size table but that took a lot of time and money so we decided to make a tiny version, which is a prototype to the big one.”

We sized this mini table for American Girl Doll height (an American Girl doll is 18″ tall so we made the table to be 9″ tall), but you can adjust and modify depending on your needs. The most important thing to keep in mind is table weight, as a larger table requires larger motors and more battery power.

Difficulty level: Intermediate

Estimated build time: a few days to a week

Cost: ~ $75 – $100

Adult supervision required (lots of sharp and powerful tools involved)

 

Supplies

Materials

  • Wood
    • Table top: 8″ x 16″ (width x length)
    • Legs: 1.5″ x 1.5″ x 8″ (width x length x height)
    • Table Shelf: 8″ x 14″
  • Brackets (8)
  • Screws (28)
    • For brackets: 1.25″ screws
  • Axle, metal
    • We used the metal rod from an old (aka broken) french press
  • 4xAA Battery case and (4) AA batteries
  • Continuous rotation servos (2)
  • Small screws to hold wheels onto servo (2)
  • Radio controller and receiver
  • Servo Wheels (2)
  • Caster Wheels (3)
    • we used the same wheels as for the servo motors, but attached them to an axle instead of a servo.

Tools

  • Hot glue dispenser and glue sticks
  • Power Drill
  • Drill Bits
  • Screwdriver Bits
  • Saw
    • Or get pieces cut at your local hardware store
  • Sandpaper
  • Glue
  • Electrical Tape or heat shrink tube
  • Safety glasses
  • Dust mask
  • Scissors
  • Measuring tape
  • Level
  • Clamps
  • Optional:
    • Duct Tape
    • Velcro
    • Zip Ties

Tips, Tricks, & Extra Information (Please read before building!)

Before you build anything, read the full project instructions first!

Helpful info to have before you start this project:

1. Be prepared for drying time

2. How to use power tools and know safety rules.

Safety rules: put hair up, eye protection, roll up sleeves, no loose clothes, no jewelry that could get in the way, always have a second person in the room especially an adult if you are younger, dust mask.

3. Be prepared w/ the materials and tools you’ll need.

4. Document in a notebook as you work for reference later.

5. Find a radio controller that comes with a receiver. It is easier to put together the electronics if you get a controller and receiver together because it will take a lot more time to figure out which receiver will work with a particular controller, so get a controller that comes w/ the right receiver.

RC controllers can be very expensive, and other ones are super cheap and don’t work well. Read the entire description for the controller and receiver that you are interested in. The way we figured it out was by finding three options: one that was expensive, one that was in the middle, and one that was cheaper. We used our budget to help figure out the best option, and ended up selecting the option that was in the middle.

Build the Table!

Gather your woodworking tools, wood pieces, and brackets (see Supplies section for sizes). Remember to measure two or three times before drilling, gluing, and/or cutting 🙂

Step 1: Determine placement of legs and brackets and mark all bracket holes with a pencil. 

We used 2 brackets for each leg and 4 screws for each bracket, except for two brackets that overlap in between the legs.

It is helpful to use a tape measure to get placement as accurate as possible.

Step 2: Attach legs to the tabletop with brackets and screws.

A. Drill small holes in the tabletop and table legs to avoid cracking the wood. (See photo)

B. Attach two brackets to each leg.

C. Attach legs with brackets to table.

Step 3: Add the table shelf!

We cut ours to fit between the legs and attached with wood glue.

Tip: Add an object under the shelf while it is drying so the shelf does not move.

 

Step 4: Sand the table where needed.

Step 5: Measure the height of the wheels and include in the total table height.

Connect the Electronics!

1. Set up the radio controller and receiver.

Bind the receiver to the controller as shown in the instructions that come with the controller that you chose.

2. Connect the battery case to the radio receiver.

Connect the battery pack to the pins that say “B/VCC” (black wire goes on the outside of the receiver).

For this table size and weight, four AA batteries are enough to power the receiver and the two continuous servo motors. If you build a bigger table, you’ll need larger motors and more battery power.

3. Do a quick test to figure out which receiver input plugs work best for driving your table with the controller.

For the test, do the following:

If you are using the same radio controller and receiver, we recommend using receiver channels 2 and 3.

A. Connect one motor to the first channel on the receiver. Align the servo wires with the receiver channel as shown in the photo above.Then move the controls on the controller, observe when and how the motor moves, and record your findings.

B. Move the motor to the next receiver channel and repeat Step 2A. Do for all channels on the receiver.

C. Decide which channels work best to drive your robotic table!

Build the Drive Train and Attach Wheels!

The drive train is how we connect the motor and wheels to the table.

Step 1: Attach the wheels to the servos.

We attached the wheels with screws, but we had to find screws that fit and held the wheels on tight. We also had to drill out a bit of the wheel where the hole is so the screws could fit through. You may need to do a bit of testing to find the proper screws.

Step 2: Figure out placement of the servos and wheels. Use tape to hold in place while you test.

Use a level to make sure that when you attach the wheels the table is not all wonky. Measure how tall the servo with wheels are going to be before you attach them and before you drill into the wood. If you do not measure them, the table might be too tall and disproportionate.

Step 3: Attach the front castor* wheels to the table using the metal axle.

A. Measure and mark the location of the axle so that the castor wheels are even with the back wheels.

B. Drill holes into the front table legs and push the axle through, adding wheels as you go.

C. Secure the castor wheels in place by adding hot glue or grommets** on either side of the wheels, leaving about a 1/2″ (1cm) gap so that the wheels can rotate freely.

*The front wheels are called “castor” wheels because they are not connected to the motor.

** A grommet is circular rubber stopper, sort of like a rubber band, that prevents the wheels from sliding off.

Step 4: Secure the servo motors with epoxy or another strong adhesive.

Note: We recommend doing this step after testing the whole table as the servo motors will be stuck once the epoxy dries.

Test, Drive, & Decorate!

Power up the radio receiver and controller and test out your robo table! It might take a few practice trials to get a feel for driving the table.

Once you’re sure the table is working, add some hot glue (or epoxy) to hold wires in place and prevent the electronics from getting disconnected.

Decorate your table with markers, paint, stickers, fabric… whatever your creativity compels you to do!

If you want to see optional upgrades, check the next slide. Otherwise….

You’re done! Enjoy driving your robo table, maybe to give your pets a lil’ exercise or to deliver you or a friend food when you are watching a movie. Share your ideas and creations with us, we’d love to see!

Optional Upgrades

Battery holder!

We made a battery holder using wood, felt, ribbon, and wood glue. We measured the battery box and cut small pieces of wood to make a box without a top. We used the felt to cushion the battery box and keep it in place, and the ribbon to more easily pull the battery box out.

Wire Tubing

We purchased some wood-colored cord cover and cut it to fit the sides of the table legs to conceal the servo wires.

Brakes!

Design your own braking system, or stay tuned for separate tutorial on how we tackle this!

micro:bit magic wand (Beginner)

 

While it is a bit tricky for us non-magical humans to levitate objects with our minds, words, or wands, we can use technology to do (basically) the same things!

This project uses two micro:bits, a few small electronic parts, and some everyday objects from around the house to create our very own magical wand.

I went for the Wingardium Leviosa spell, but you can most certainly adapt this project to cast other spells 🙂

Difficulty: Beginner+ (a lil’ bit of experience w/ coding and circuits is helpful)

Read Time: 10 min

Build Time: ~ 2 hrs

Cost: ~ $35

Materials

  • Wand!
    • You can purchase custom wands or make your own! Find a suitable stick and add some flair (or leave it bare!), or get creative and make one out of things you can find around the house!
  • Feather (for floating!)
  • Glove (for hiding the micro:bit wand controller)
  • Aluminum can
  • Small piece of cardboard (~ 2″ x 2″/5cm x 5cm)

What are we doing??

One of my favorite scenes from the first Harry Potter book was when, after all of the other students are struggling, Hermoine makes a feather float with the spell Wingardium Leviosa. This simple spell captures the essence of why we love magic: that literally at the flick of our wrist and a few choice words, we can instantly make surprising (and impressive) things happen.

Although we don’t have exactly that kind of magic, we do have technology that sometimes seems miraculous. So that sort of counts!

By now you’ve probably guessed: To mimic my fav scene, I wanted to levitate a feather. For that, we can use the power of wind! For this beginner-friendly tutorial, I chose to use a small 5V DC motor with fan blades made from an aluminum can. You can imitate my design or, better yet, create your own!

This tutorial will show you how to do the following:

1. Write a simple block-based code for a micro:bit wand controller

2. Build a circuit to control a small, 5V DC motor

3. Write a simple block-based code for a magical receiver that is triggered with a radio signal (aka bluetooth)

4. Build a setup to make our tech really look like magic!

 

Code it: Wand Controller!

Let’s start with our magic wand!

Since this is a beginner-friendly project, we are using block-based coding on the Make Code website. If you have more experience w/ coding you can also program the micro:bit using micropython or C++ in your fav coding environment (e.g. Idle, Visual Studio Code, etc.).

Alright, let’s get blockin’!

Step 1: In the On Start block, set the Radio Group number. 

Pick a number you love and will remember, since we’ll also need this for the receiver.

Step 2: Decide how you want your wand to trigger action.

The micro:bit has an accelerometer which measures changes in acceleration in our three spatial dimensions: up/down, left/right, and forwards/backwards.

Quick solution: Use the “on shake” block! (Code 1, above photo)

More complex, gesture-based solution: Explore how the accelerometer works and observe the output as you make gestures (open the Arduino IDE Serial Monitor to see the output, if you need help with this check out this tutorial). Use your observations to set triggers. (Code 2 in the above photo)

The example in Code 2 is my attempt at a Wingardium Leviosa gesture: swish-and-flick! (down and left) Use it as-is or as a starting point for your own fav magical gesture!

Helpful Tips:

(1) Since microcontrollers process information super quickly, the pause block gives us time to finish the first part of the gesture before the micro:bit checks for the second part.

(2) I added axes labels on the micro:bit so I could more easily figure out how to get the right motion for Wingardium Leviosa spell — definitely recommend this!

Step 3: Use the gesture to send a radio number.

The “radio send number” block is found in the “radio” block set. Any (rational, real, non-infinite) number will work!

Step 4: Download and save the code onto the micro:bit!

The micro:bit power lights will flash as this is happening, when they are done flashing the code is finished uploading.

Build it: Magical Receiver!

Grab your second micro:bit, your breadboard, and all the fun electronic parts and pieces!

Step 1: Insert your MOSFET transistor into the breadboard.

Recommended to have the black part of the transistor facing you so that pin references in these instructions are accurate 🙂

Step 2: Grab one of your pin-ended alligator clips and connect it from micro:bit pin P0 to an open row in the breadboard.

Step 3: Connect your resistor between the micro:bit P0 wire and the MOSFET Gate pin (leftmost pin).

Step 4: Connect a pin-ended alligator clip between micro:bit GND pin and the MOSFET source pin (rightmost pin).

Step 5: Using your two remaining pin-ended alligator clips, connect the motor leads to two open rows in the breadboard.

Step 6: Connect your jumper wire from one of the motor wires to the MOSFET drain pin (middle pin).

Step 7: Connect your diode across the motor terminals so that the negative side (w/ the stripe) connects to the remaining motor wire (yellow wire in photo).

Step 8: Connect the negative (black) battery lead to the MOSFET source pin (same row as micro:bit GND).

Step 9: Connect the positive (red) battery lead to the remaining motor wire (yellow wire).

Code it: Magical Receiver!

Step 1: Set Radio Group to be the same as for the Wand Controller.

Step 2: Pull out a “on radio received” block and set it to “receivedNumber”.

Step 3: Drag a repeat block into the “on radio received” block and switch it to repeat 2 – 3 times.

Step 4: (Optional but recommended) Show an icon on the micro:bit to let you know if it received the string.

This is super duper helpful for debugging.

Step 5: Turn on Digital Pin 0! (aka “digital write pin P0” to 1)

This block is found under the “Pins” block under the Advanced tab.

Step 6: Pause for a few seconds.

I chose 4 seconds, you can keep this or adjust as desired.

Step 7: Turn off Digital Pin 0 (“digital write pin P0” to 0) and the micro:bit display.

Step 8 (Optional but recommended): Add a back-up trigger using micro:bit button A for testing and debugging purposes 🙂

Voila! Download the code onto your Magical Receiver micro:bit and we’re ready for the magical prop!

Let’s make wind!

Let’s make a wind generator!! AKA a fan 🙂 Turn on a hot glue gun and grab your scissors, permanent marker, aluminum can, and some cardboard.

Step 1: Carefully cut out a rectangle of aluminum from an empty can and a small circle of cardboard about 1/2″ (1 cm) in diameter.

 

Step 2: Print out the paper fan template above at 50% to scale. Cut out one of the fan blades and trace it five (5) times onto the aluminum foil.

Step 3: Carefully cut out the aluminum fan blades and glue onto the cardboard circle at equal intervals.

Step 4: Glue the motor mount onto a piece of cardboard (I also added “legs’ made of wooden dowels to make it easier to connect the alligator clips).

Other options:

  • Use the motor drive shaft to spin objects or make some gears/levers to move things in different directions
  • If you connect micro:bit to speakers, it can also play sounds!
  • Start with something simple and play around to find something that makes you feel magical.

Test all the things!

And now, for our favorite part: testing!! Power up your micro:bits (and connect the battery) and move your wand controller (or use the quick button trigger) to test that our magical receiver moves the motor.

When you are done testing, coat the magical receiver connections in hot glue to hold them in place. If you want an ultra-permanent solution, use epoxy (waterproof is a nice bonus feature). Be careful to avoid getting glue (and especially epoxy) on your micro:bits so that you can still use them for future projects!

Note: When you first power everything up, the motor may start spinning without a signal. Trigger the wand controller and it should stop, then behave as expected.

Not working as expected?

Debugging is an almost inevitable part of building things, so congratulations! You are officially a maker! Here are some debugging tips:

1. Power is the most common issue for makers of all experience levels. Double check that the battery is properly connected and both the micro:bit power lights are on (those little yellow lights by the microUSB port).

2. Motor not moving? Be sure none of the wires or other objects are in the way.

3. Motor pulling the feather towards it rather than away? Swap the orientation of the motor leads. This will cause the motor to spin in the opposite direction and thus the air will be pushed in the opposite direction.

Make all the magic!

We’re basically wizards now! Use gloves to hide and hold the micro:bit wand controller and battery pack. Hide your magical receiver in a fantastical container to really impress all the people. I snagged a hollow book stack, cut a hole in the top, and glued my motor with the fan inside.

That’s it! Practice your spell and impress your friends with your new-found powers.

Questions, comments, creations? Leave a comment! Happy making, you magical beings!

Build an (easy) Floor Piano!

The household floor piano is a dream no more! The Makey Makey microcontroller makes it super easy (and affordable) to build your very own “foot-strument” out of common household materials.

Grab a Makey Makey kit, some cardboard, and your musician shoes and let’s get building!

  • Difficulty Level: Easy
  • Estimated Build Time: 60 minutes
  • Cost: $50 (for Makey Makey kit)

 

 

Materials & Tools

Materials

  • Makey Makey Kit
    • 16 Breadboard Jumper Wires
    • 4 Alligator Clips
  • Cardboard
  • Aluminum Foil
  • Plastic Trash Bag (stretchy is best)
  • Duct Tape

Tools

  • Scissors
  • Hot Glue Gun
  • Measuring Tape or Ruler

 

Build the Piano!

1. Build the piano base.

Cut a cardboard base for your keyboard, then divide it into 8 equally sized rectangles — these are the dimensions for your piano keys!

2. Make the piano keys!

Cut out 8 cardboard rectangles using the base dimensions and paint them white.

3. Build the key triggers for the piano.

Cut 16 cardboard rectangles of equal size or smaller than the cardboard piano keys.

Repeat the following for each pair of key triggers:

  • Cover both cardboard rectangles in aluminum foil.

  • Use copper tape to connect one wire to the aluminum foil on each of the key triggers, then cover the connection in duct tape to secure.

  • Cover one of the rectangles with a piece of the plastic trash bag so that the aluminum foil is completely covered. Secure with duct tape.
  • Sandwich the two key triggers together so that the trash bag is a barrier between the aluminum foil.

 

Connect to the Makey Makey!

1. Connect the wires to the Makey Makey – one of the wires goes to ground and the other goes to a keypad (doesn’t matter which wire).

2. Test that the Makey Makey is triggered when you put pressure on the cardboard.

3. Tape the key triggers to the bottom of the white cardboard piano keys. Secure them to the piano base with velcro or glue.

4. Connect one of the wires from each of the key trigger to the six header pins on the back of the Makey Makey board and to two of the arrow keys on the front.

5. Connect the other key trigger wires to the Makey Makey ground.

Recommended to connect the ground wires in two groups of 4, then use one alligator clip per each group of 4.

Write the Scratch Program!

We have 8 inputs, which means we can play an entire octave on our floor piano! (Yes, that was intentional).

Your job: Write a Scratch program that plays 8 successive keys starting at middle C (or wherever you prefer your piano octave to start) using the “play note” function. Or you can copy mine in the photo above 🙂

Aside from the program, just be mindful of what piano key is connected to what Makey Makey pin. It’s easy to get 8 wires a bit mixed up — consider labeling them to save yourself some time (& hair..).

Install & Play!

Consider coating the electrical connections in hot glue. Plug the Makey Makey into your computer, place your floor piano on, well, the floor, and have at it!

Enjoy making beautiful music by stomping on your custom creation.

Micro:Bit Puppet “Text Message” System

Intro

Nearly all of our wireless communication is done using radio waves*, including phone calls, text messages, and WiFi. With its built-in radio transmitters and receivers, the Micro:Bit microcontroller makes it super easy to build all sorts of projects with radio communication.

This particular project is a simple & quick way to send text messages between two Micro:Bit** microcontrollers – the sender writes a (short) message that is transmitted via radio to the receiving Micro:Bit, which shakes a lil’ puppet using a servo motor, and then displays the message on the Micro:Bit LED screen. Each Micro:Bit can be both a sender and receiver.

It’s sort of like a two-person Twitter.. if the tweet notified you via dancing cardboard robot puppet!

*Radio waves are long-wavelength light waves. Check out the electromagnetic spectrum here!

**A huge THANK YOU to Adafruit for donating the Micro:Bit microcontrollers used in this project for educational purposes! yayy thank you for supporting this educational endeavor!! 😀

Materials & Tools

Electronics

Puppet (or other Message Alert System) Materials

Tools

  • Hot Glue Gun
  • Scissors and/or utility knife (e.g. exacto knife)
  • Pencil
  • Ruler or other straightedge

Build the Incoming Message Alert Puppet!

Step 1: Build a cardboard puppet like the one shown in the photo or create your own! Use the paper fasteners to make joints.

Step 2: Build a mounting system to attach the puppet to the servo with skewers and cardboard.

I used a magnet to attach the puppet to the servo mounting system because magnets are awesome, but you can also use glue, tape, velcro, or a variety of other adhesives!

Step 3: Build a stand for the puppet.

  • On an approx. 6 in. x 12 in. cardboard sheet, measure, mark, and cut a hole for the servo body so that the arms of the servo rest against the front of the cardboard sheet.
  • Cut two triangles out of cardboard and glue them on the back of the stand so that the stand, well, stands upright!
  • Cut a hole for the Micro:Bit wires to thread through and add two pushpins on the front to hold the Micro:Bit.

 

 

 

 

 

 

 

Code the Two Micro:Bits!

To start, choose one Micro:Bit to be the sender and the other Micro:Bit to be the receiver. Once both are working as expected, add in the code for both roles.

Use the Make Code Micro:Bit website to program each Micro:Bit. As this is intended as a beginner project, the whole system can be built using the block-based programming language, although adaptations are encouraged and appreciated!

If there is more than one pair of Micro:Bits in the room (i.e. in a classroom setting), remember to set different radio group numbers for each pair.

The sender sends a (short) text based on user inputs over radio, like the example above. Pretty simple!

The receiver moves the servo when an incoming text is received, then scrolls the message text on the LED screen, like in the example below.

Press the reset button to stop sending/receiving the incoming message.

 

Connect the Servo!

Connect the servo red wire to the Micro:Bit 3V power pin, the servo black wire to Micro:Bit ground pin, and the servo white (or yellow) wire to the Micro:Bit input pin P0.

Send all the Messages!

Program both Micro:Bits to be both a sender and a receiver so you can communicate back and forth. Then switch power from the laptop to the battery pack and test out your wireless communication system! When the sender sends a message, the puppet will notify you to check the LED screen so that you can see the incoming message.

How far of a range can you get? Test it out!

There are tons of other extensions to this introductory project, here are some possibilities:

  • Add more message options by adding more inputs or changing how those inputs are read;
  • Instead of a table-top alert system, build a wearable alert system;
  • Send voice messages and/or other sounds.

Happy building!

Make Custom (& Inexpensive) Circuit Blocks!

Create, build, and play with your very own LEGO-inspired circuit blocks! Explore the basics of electricity and circuits, discover how sensors work and use ’em to design your own experiments, and incorporate upcycled materials to improve on your materials-sourcing & MacGuyver-ing skills! That old gum wrapper? Make it into a resistor or a switch!

But seriously, this is a super fun (and inexpensive) project/toy/game to teach electronics to kids (and adults!) of all ages and experience levels. The total cost of this project is under $30 and it takes about 2 hours to design and build.

 

Ok.. so where do we start?

First we need a base, the circuit block itself. This design uses breadboards* as the circuit block bases. I chose mini color breadboards so that each color denotes a specific type of electronic component (see next section). These are super cheap, typically less than $1 per board. Follow my design or create your own!

For each breadboard/component, we also need at least two or more breadboard wires (or 22 or 24 stranded wire), so for 20 breadboards with a single component we need 40 or more breadboard wires.

*Breadboards are non-edible, inexpensive prototyping boards for electronics projects. See photo above for a quick illustration of how breadboards work, or check out this tutorial.

 

Gather Electronic Components!

If you happen to have an assortment of electronic components around, gather them up and go through them to find the most choice pieces — we want components with only two leads, like simple motors, fans, LEDs, resistors, capacitors, etc. Check out websites like SparkFun or Amazon and search for electronic components.

Hey, wait, where can I get this stuff for free??

Dig up that box of broken electronics in your garage and see what you can find inside the electronics!

The best sources for components are electronic toys that move and/or make noise, speakers, telephones, and other medium-sized electronics.You’ll need wire cutters and pliers to remove the pieces, be sure to keep the legs intact so they can easily connect to the breadboard.

Avoid smartphones, tablets and laptops since the circuit components are suuuuper small and difficult to attach to a breadboard (unless that’s what you’re going for, then extract away!). For safety reasons, avoid appliances (e.g. microwaves, televisions, refrigerators, etc.), and do not use capacitors that are larger than a child’s thumb.

 

Build the Circuit Blocks!

The breadboard assortment I got included red, blue, white, green and black, mini breadboards. I broke up the colors into the following categories and components:

 

Red boards (power devices): One 1 W solar panel, one 9V battery clip, one 2 AA battery box, and two coin cell cases.

 

 

 

Blue boards (simple active): one motor w/ propeller, six LEDs of different colors (three per board), and one transistor (the transistor is pretty tricky — I’d recommend replacing this with another motor).

 

 

 

Green boards (sensors): one photoresistor, one buzzer/piezoelectric sensor, one peltier junction, and one capacitive sensor (this didn’t end up working, so replace it with a pressure sensor or other cool, two-lead sensor).

 

 

 

White boards (simple passive): six resistors of varying values (three per board), two (small electrolytic) capacitors of different values, and one potentiometer.

 

 

 

 

Black boards (electromechanical): Two pushbutton switches of different sizes/types (one per board), two toggle switches (single board), and one cooling fan.

 

 

 

To build each circuit block:
Connect each component to the first rows of each breadboard (be sure they aren’t shorted — should be on either side of the breadboard), and hot glue the wires into place. Remember to label which side is positive and which side is negative! Another fun option is to make labels for each component.

 

Plug & Play!

You’re ready to start building circuits and teaching other people the basics of electronics! Start simple, then add in more components to explore their function and see how they affect your circuit.

Here’s an example progression exploring different ways to light up an LED:

1. Use a coin cell to light up an LED.

Exploration questions: Does orientation matter? Where do the wires need to connect to the breadboard?

2. Use the solar panel to light up an LED. Move the panel into the shade (or cover it with your hand), and see how the LED brightness changes.

Exploration questions: How does the brightness of the LED change when you cover the solar panel? Why does this happen?

3. Use a coin cell and potentiometer to adjust the brightness of an LED.

Exploration questions: What do you notice? Does it matter how we connect the potentiometer?

4. Use a coin cell and a photoresistor to adjust the brightness of an LED.

Exploration questions: What do you notice?. Does it matter how we connect the photoresistor? How could we use the photoresistor in an experiment?

Build your own sequences to teach folks about specific circuit components or sensors, or use them as a fun & educational free-time project!

LED Proximity Sensor Gloves

This is a minimalistic design for a proximity sensor glove: a light-up glove that dims in brightness when an object, or person, is close to the sensor. This project costs less than $10, although it does take some time to build (1 – 2 hrs).

This is also a modular design, meaning that it is easily customizable and can be used in other projects.

Here’s a video showing the glove in action.

Materials

  • Gloves (fingertips optional)
    Pretty much any type of glove will work. I chose simple cotton ones (that are well worn and have character) because it’s easy to sew components into these gloves and, if necessary, can easily (& cheaply) be replaced.
  • LEDs! I had 5mm white LEDs on-hand, so I used 10 for one glove. As long as each LED has appropriate resistance, you can (pretty much) add as many as you want.
    I strongly recommend getting surface mount LEDs or wearable LEDs. They are a bit more expensive, but are much more aesthetic for this type of project and are waay easier to sew.
  • Conductive thread
    This is one way to connect + attach the LEDs. I chose conductive thread b/c it looks cool and incorporates the circuit into the glove material, acting as both a conductor and an adhesive. Other options include wire or alligator clips.
    Disclaimer: When using conductive thread, be super careful of short circuits. I set my conductive thread on fire more than once during this build process..
  • Photoresistor
  • Five 1 KOhm resistors (one for each pair of LEDs) The value and number of your resistors may change depending on your battery + LED type.
  • 9V battery + battery clip
  • Switch (optional)

Tools

  • Scissors
  • Sewing needle
  • Hot glue gun, epoxy, or other quick-drying adhesive.
  • Soldering iron (optional) You can build the glove without a soldering iron by tying conductive thread tightly to a component, then coating in hot glue or other adhesive.
  • Multimeter (highly recommended) A multimeter is super useful for checking electrical connections.

Build it! Pt. 1

If a breadboard is available, use it to test the circuit.

  1. If you have a switch, connect one end to a battery clip lead.
    Solder the two wires together, or use conductive thread + hot glue.
  2. Determine layout of the photoresistor(s), LEDs, and resistors.
    You can follow my schematic or you can add more LEDs and/or photoresistors (recommended b/c it’s cooler). Here’s a helpful website to calculate the circuit resistance. Remember that the photocell also adds some resistance (mine was between 300 Ohms and 1 MOhm).
    In my layout, two LEDs are connected in series with a resistor, as in the breadboard photo above. These in-series LED pairs are then connected in parallel with all other in-series LED pairs.
    Aside: Diode forward voltage & current depends on the color. These white LEDs were ~ 3.4 VDC and 20 mA. Use Google or this page to find forward voltage and current for your specific LEDs.
  3. Turn glove inside out and mark location of the LEDs, resistors and photoresistor(s).
  4. Sketch the positive and negative connections onto the glove w/ a pen. Label the + and – lines.
    This step is especially helpful b/c 3D circuits can be a bit confusing.

Build it! Pt. 2

  1. f68ghgsi1cc12bw-largeAttach the photoresistor to the glove (and add a positive battery lead to the glove).
    Make a slit in the glove or push the photoresistor wire legs through the fabric (be sure the legs are on the inside of the glove). To hold it in place, dab hot glue or sew legs to glove with regular thread.Tie conductive thread to one end of the photoresistor (either leg works), and sew thread through the
    glove to the bottom. Leave a few inches of thread at the end for the the
    battery connection. Coat connection in hot glue.
  2. Attach a resistor to the positive leg of one LED. Repeat for one LED in each set of LEDs that are in-series (5x for this configuration).
    Wrap the two ends together and, if possible, solder the connection. Remove excess wire and coat in hot-glue to adhere connection and cover sharp ends.

Build it! Pt. 3

  1. Attach the LED + resistor to the glove.
    Poke the ends of the LED through the glove (or make a slit). Tie conductive thread to LED legs and coat in hot glue to hold components in place, and to cover sharp ends.
    Be careful to avoid shorting the LED legs with the conductive thread. 
  2. Connect the LED + resistor to the open leg of the photoresistor. Sew conductive thread from the resistor leg to the photoresistor leg, then tightly tie thread to photoresistor leg. Coat connections in hot glue.
  3. Connect the next in-series LED.
    Connect the positive leg of the next in series LED to negative leg of the previous LED.
    Depending on the type and number of LEDs you are using, you may have one, two or more LEDs in series w/ the first LED + resistor.
  4. Repeat Steps 1 – 3 for all LEDs in parallel.

Build it! Pt. 4

  1. Once all the LEDs + resistors have been installed, add in a negative battery lead.
    Consider where you want to put the battery before adding in leads. You can attach the battery directly to the glove, hide it inside the glove, or install long leads to allow the battery to be placed elsewhere on your body.
    My initial design used conductive thread for both battery leads, but this shorted the glove so many times I replaced them with an alligator clip in the final design. This works much better, is safer, and is seriously recommended over conductive thread. If you don’t have an alligator clip, any insulated wire will work.
  2. Label the positive and negative battery leads.
  3. Optional: Solder the battery clip leads to the glove battery leads and dab with hot glue.
    Alternative options include alligator clips or twisting wires together + coating with hot glue.

 

Test & Wear!

fsceucvi697s4r1-large Be sure to test your design BEFORE you wear it because if there are shorts in the conductive thread it will probably catch fire. So, please be careful and be sure that the positive and negative sides of the circuit do not touch.

The connections can be a bit finicky. Be patient and check the electrical connections w/ the battery or a multimeter (if you use a battery, be careful to avoid shorting the circuit). Fix and add more hot glue as necessary.
Once you know it works, put on the glove(s) and impress your friends!
Happy hacking!

Versatile Wearable LEDs

Wearables (aka Wearable Technology) are a new & insanely awesome extension of electronics. These minimalistic, versatile, and detachable lights are designed to allow for a wide variety of creative possibilities and to be accessible to makers of all ages and backgrounds.

The process takes about an hour and materials costs are less than $10 per LED strip (not including the battery). Even the pooch can have a light-up sweater!

Materials

F5XUSANI5BSIUH2.LARGE

  • LED strip(s)
    Here’s a link to purchase the specific LED strips used in this project: 12 white surface LEDs with a forward voltage of 7.4 – 15 V and forward current of 50 mA.
    If using different LEDs, note the forward voltage & forward current and use this calculator to determine the necessary resistance.
  • Male and Female JST connectors
    The Tarot LED strips came assembled w/ male JST connectors, so those were the easiest & most practical. They work rather nicely for this project, and I recommend using them if you are new to electronics.
  • 33 Ohm Resistor
  • Switch
    So many options for switches! For this project, I suggest an SPST (single-pole-single-throw) maintaining switch (aka toggle or on/off switch). I had a DPDT slide switch on-hand so that’s what I used for this tutorial.
  • 9V battery (preferably rechargeable)
    Any battery w/ a voltage output from 7.4 -15 V works. LiPo batteries are the best (and last the longest), but are more expensive.
  • Velcro (sticky side only)
  • Optional: Custom Battery Case
    • Version 1: Two safety pins & a 3″ x 2″ piece of fabric.
    • Version 2: Strong rare earth magnet (or two).
      This is a more expensive but simpler alternative to the fabric battery case.

    Tools

    FE4K749I5BSIUPO.LARGE

  • Soldering iron
  • Hot Glue Gun
  • Wire Strippers
  • Needle + Thread
  • Scissors
  • Recommended: Epoxy
    My favorite method to make extremely permanent (+ weather resistant) electrical connections.
  • Also recommended: Multimeter & Breadboard (for testing)

Build it! Pt. 1

FI4XPL6I5F7SBER.LARGE

FG0506RI5DSOCOS.LARGE

FM4N54YI5DSOCU9.LARGEPrep: If LEDs lack wires, solder the male JST connector leads to the uppermost LED pads. Coat in a dab of epoxy or hot glue.
Recommended to test the circuit on a breadboard before soldering.

  1. Attach sticky-side velcro pieces to LED strips.
  2. Solder the female JST connector leads to the switch.

FQ442PGI5BSI384.LARGEIf using a DPDT switch, as in the schematic, each set of legs can control a separate circuit. Instead of connecting ground to the switch, you can also connect the LED ground to the battery ground. This allows you to control another set of LEDs (+ resistor) on the same switch + battery.
If you’re just starting out, here’s a helpful guide on switches.

FQBATSPI5BSI3EH.LARGEBuild it! Pt. 2

  1. Solder the resistor to the middle switch pin on the same side as the positive JST wire.
  2. Solder the positive lead of the battery clip to the resistor & the negative lead to the negative middle switch pin (or connect them together).
    Clip off excess wires.
  3. F4NBVIRI5BSI3O3.LARGEConnect LED strips via the JST connectors and check that the switch works.
  4. Coat bottom of switch in epoxy and/or hot glue.Be sure to avoid getting glue on the moving part of the switch esp. if using epoxy. Check that it can move while epoxy is drying.FBYXZ9RI5BSI4C7.LARGE

Build it! Pt 3 (9V Battery Case)F1UNDDJI5BSI56D.LARGE

  1. Sew your chosen fabric square into a pocket for the 9V.
  2. Place 9V battery in case and attach the battery clip.
  3. F9YO86DI5BSI77T.LARGESew battery clip + switch to back of fabric case (face switch outward).
  4. Attach safety pins to back of fabric case.

FCUYRXQI5BSI6W7.LARGE

For magnet battery holder alternative:

Some rechargeable batteries, such as NiMH (Nickle Metal Hydride), are magnetic. For these, place battery inside clothing, then place magnet on the outside to hold the battery in place.
If the battery is non-magnetic (e.g. lithium), hot glue one magnet to the battery, place inside clothing, then place another magnet on the outside of your clothing. Be sure to keep the magnet when switching out the battery!

Test & Wear!

F19M5H9I5BSI6PU.LARGEDouble check that the switch successfully turns on and off the LEDs. Attach the battery+switch to clothing by safety pinning (or magnetically attaching) the battery to a comfortable place. The velcro adheres best to soft fabrics, like sweaters, tights, fleece, etc.

Be creative and experiment with the basic module on assorted clothing and accessories for yourself, your friends and your pet(s)!

F6PT0XDI5DS9QJ2.MEDIUM

Portable Solar USB Charger

Portable USB chargers are incredibly useful for adventures in the great outdoors, festivals, traveling, or if you are out-and-about all day. Adding in a solar panel provides an additional source of portable power useable (nearly) everywhere.
The whole project can be built for ~ $20, even if you don’t have a soldering iron!

Parts

  • 1.5W Solar Panel 9V
    • Suggested to use a low-power solar panel, typically if you are not using a charge controller.  
    • Note that the solar panel voltage output MUST be higher than the battery output for it to actually charge
  • 1N914 or similar diode
    • This protects the solar panel by allowing current to flow only from the panel to the batteries (aka prevents discharge from the batteries onto the solar panel).
    • If you choose a similar diode, be sure it works w/ the given solar panel specs (voltage/current output).
  • USB car charger
  • Rechargeable 9 V battery**
  • Battery holder for 9V (or use alligator clips)
  • Project container (e.g. tupperwear, altoids tin, cookie tin, etc.). Be creative!

Tools

  • Wire strippers
    • Scissors also work. To strip the wire, make cuts on both sides and pull off insulation w/ your fingers.
  • Electrical Tape
  • 5-minute epoxy, or other similar adhesive (gorilla glue probably works)
    • Other methods for making electrical connections: twist wires together and coat in epoxy. Other connections can be MacGyvered together; take apart old electronics for connectors and wires, use paperclips, and be creative w/ conductive objects like pennies.
  • Multimeter, if available. Massively helpful for testing electrical connections and checking if the circuit works as expected.

Background Info

advenira.com
advenira.com

Solar panels are awesome for many reasons:

  1. Renewable energy technology, woo!
  2. Handy in remote locations (like Burning Man..).
  3. Lifetime of 25 – 30 years.
    etc.*
SOLAR-WIND.CO.UK
SOLAR-WIND.CO.UK

Solar panels, or photovoltaic (PV) panels, output direct current (DC). Digital devices, like cellphones or iPods, run on DC. This means our charging circuit is fairly simple. As in the photo on the left, we need a panel, a battery, and our device, or load. Charge controllers regulate current flow primarily to protect the battery. We can avoid using one in our USB charger, but they are ideal for larger systems.

The solar charging system works w/out the batteries. The batteries are there so you can use the system whenever you need it.

 

A lil’ bit about USBUSB_pinout

As shown in the photo to the right, USB chargers have 4 pins. All USB chargers output 5 Volts (V) DC on the USB Vcc pin. However, the amount of output current depends on the type of USB charger. There are three main types: a standard downstream port (500 mA), a charging downstream port (1500 mA), and a dedicated charging port (900 mA).

Apple USB is a bit trickier (unsurprisingly..); one of the data pins is set to 2.7 VDC. So, if you finish your portable USB charger and you want to charge an iPhone or iPod, you need to increase the voltage (aka use a bigger battery.. or two 9V batteries connected together in series.

Build ProcessSolar_USB_Charger

Note: if you are using the epoxy method for connecting wires, wait until after you’ve tested the whole system to coat w/ epoxy..  epoxy is rather permanent and once it is set there is little you can do besides curse at it (won’t really help, but might make you feel better!).

  1. Strip wire on end of solar panel (remove colored insulation to expose the metal).IMG_4626

    No leads on the panel and there’s no soldering iron?! It’s all good! Get creative.
    Here’s one way: tape two wires onto the metal pads on the back of the panel w/ electrical tape (colors don’t really matter, but convention is red = positive and black = negative). Test it w/ a multimeter, or by connecting the leads to the USB car charger to make the “charging” LED light turn on. Coat in epoxy, let dry & you’re done!
  2. Connect diode to positive end of solar panel lead. If possible, solder the two ends together. Otherwise, twist wires & coat in epoxy at the end. Super important: install the diode so that the side w/ the silver band is connected to the battery, like in the photo to the right.
  3. Connect diode to positive (red) side of battery holder. Connect negative (black) solar panel lead to negative battery holder lead.IMG_4643
  4. The front metal part of the USB car charger is the positive terminal. One of the metal side tabs is the negative terminal. Determine which side of the USB car charger is the negative (or ground) side.
    Here are a couple easy ways:
    — Open up the charger; see which metal tab is connected to a wire.
    — Use the panel to turn on the charger. Connect the positive battery/solar panel lead to the front metal lead. Touch the negative battery/solar panel lead to each side. The side that causes the “on” light to light up is the negative side.
    IMG_4580
  5. Connect the negative battery/solar panel lead to the negative tab on the USB car charger. Connect the positive battery/solar panel lead to the front metal lead on the USB car charger.
    There are a few ways to do this, depending on your available tools and materials. The easiest way is to use alligator clips (and coat them in epoxy when it’s all done & tested).
    IMG_4646IMG_4645
  6. Test it! Connect a USB device (like the Raspberry Pi!!) and make sure it lights up.
    If it works, epoxy all the electrical connections, put it into a container and take it w/ you on an adventure!
    Once your first version works, make upgrades and modifications as necessary! Google is super helpful.

IMG_4649

*More info about solar!

Solar panels have a relatively low energy efficiency rating, typically around 12-15%. Research is continually improving solar efficiency, and a lab in Germany set the world record for solar cell efficiency at 44.7%.

In 2012, average costs of solar per watt were between $1 – $2, with some as low as $0.70 per watt. Although this does not include the cost of additional equipment (e.g. batteries, transformer for AC applications, mounting system, etc.), it is beginning to seriously compete with fossil fuels. Yay, solar!!

**Why a 9 V battery?

USB car chargers expect 12 VDC from the car, but will accept between 6 VDC and 14.5 VDC. Using a single 9V battery is the easiest way to get a sufficient input voltage for this USB circuit in order to get an output of 5 VDC.