Tappy Hand

This project combines very basic materials to create an entrancing hand that can be "programmed" to move its fingers in different sequences.

The Electronics

This project is based around the Circuit Playground Express. This board is packed with sensors and is easy to program using the block-based code editor MakeCode.

Power

If you'd like to power your project without connecting a USB cable to your computer either of these battery options work well to untether your device.

Other Materials

In addition to the electronics, for this project you will need:

• A known good A to micro-B USB cable
• Scrap corrugated cardboard
• Scissors and/or box cutter
• Hot glue gun
• Hot glue sticks 
• A bamboo skewer

Rotating Drum

The central component of this robotic hand is the spinning drum. This drum has different slots that can hold squares of cardboard in different positions. 

Test your rotating drum out by sliding some bits of cardboard into the gaps. They should grip the cardboard firmly, but still allow you to slide them back and forth without too much effort.

If you find the grip too loose, add another small line of hot glue to the edge. If the grip is too tight, squeeze the cardboard square to flatten it slightly, the corrugation inside should give it enough spring to still fit tightly into place.

Make Fingers

Cut out four crescent shapes for fingers.

When you're finished you should be able to spin the axle and see it rotate freely within the fingers.

Complete the Circuit

Connect the Vout pad on Circuit Playground Express (CPX) to the servo's red wire, the A1 pad to the yellow wire, and the GND pad to the brown wire. 

The alligator clip-to-male jumper wire connectors are great for connecting servo motors to CPX.

Your hand is now ready for some MakeCode!

Getting Familiar

Microsoft MakeCode for Adafruit is a web-based code editor that provides a block editor, similar to Scratch or Code.org, and also a JavaScript editor for more advanced users.

If you'd like to learn more about MakeCode, this guide is a good place to start.

How to Upload Code

To upload code, first connect your Circuit Playground Express to your computer using a micro USB cable and press the small reset button in the center of the board. All the LEDs will flash red briefly, then turn green. Your computer should now show a removable drive called CPLAYBOOT. 

Click the Download button in the code window below to download the .uf2 file to your computer, and drag 'n drop that .UF2 file onto the CPLAYBOOT drive in your computer's file explorer or finder.

The drive will automatically eject itself (your computer may give you a "failed to eject drive correctly" error, you can ignore this). The code is now on your Circuit Playground Express and ready to run!

Use

Press button A for the project to run.

Extended Runtime

If you'd like your motor to spin for longer, it's easy to drag some extra pause blocks into your code. 

Exploring Inputs

MakeCode allows you to very quickly adapt a program to respond to different inputs.

Rather than using a button press to trigger the hand, you can set it to start moving when it detects movement, or when light, temperature, or noise levels change.

Motor Speed

Adjusting the speed of a continuous rotation servo can be accomplished by adjusting the potentiometer hidden inside the motor.

Take a small screwdriver and SLOWLY turn the potentiometer screw clockwise, then counter-clockwise, observing how this affects the speed and direction of the motor until you find a spot that works well for you.

Troubleshooting

Problem: My motor doesn't move!

Solution: Make sure that your Circuit Playground Express is connected to a power source (anywhere between 3V-5V is safe). If you're using a AAAx3 battery pack, check that the switch on the battery pack is set to "ON".

 

Problem: My Circuit Playground Express doesn't show up as CPLAYBOOT

Solutions:

1. Be sure you have a Circuit Playground Express.  The Classic will not work with MakeCode.
2. Some USB cables are "charge-only" and won't pass data. Try using a different USB cable and try using a different USB port on your computer.  
3. With the Circuit Playground plugged into your computer with a micro USB cable, click the small reset button in the center of the board. The lights should all turn green. If they don't, try double-clicking the reset button.

If things still aren't working, head over to the Intro to Circuit Playground Express guide for more suggestions.

More MakeCode!

If you enjoy MakeCode and want to continue exploring you can check out lots more MakeCode projects on the Adafruit Learn System.

Want to Get Back to CircuitPython?

If you ever need to convert your Circuit Playground Express back to CircuitPython mode, you can do so by downloading the appropriate .UF2 file from CircuitPython.org and dragging it over onto your CPLAYBOOT drive. See this guide page for the step-by-step instructions.