Quick Maker Project - Counting down 20s while you wash your hands with Circuit Playground Express

20s countdown timer maker project banner

Everyone has a wee song to sing to while washing your hands for 20 seconds, since I had Adafruit's Circuit Playground Express handy, why not create a visual countdown.

👉 You will need:

  • 1 x Circuit Playground Express (aka CPX)
  • 1 x MicroUSB to USB cable (so the CPX can talk to your computer)
  • Laptop
  • Editor of choice, I chose Mu Editor as it recognises Adafruit components and quick way to change and upload code as well as debugging, etc.
  • CircuitPython for CPX installed
  • Battery to power the CPX

🧐 Why did I choose Adafruit's Circuit Playground Express?

I had one around and I wanted to put something useful on it, plus I want to play a little more with CircuitPython. The CPX has 10 bright LEDS (Neopixels) so perfect for the 20 second countdown.

It also has a "Microphone Audio Sensor" so it can pick up sounds. And there's already code handily written on detecting sound via Adafruit's Sound example.

ℹī¸ More info about CPX

All the elements are there, so let's get started! đŸ’Ē

🤔 What I wanted to do

  • Clap hands to initiate the countdown
  • Changes colour and flashes a couple of times to let you know it heard your clap, and it gives you time to turn on tap, get soup on your hands
  • Each Neopixel comes on for the 1st 10 seconds going clockwise, as it reaches the end, all Neopixels turns off and each one lights up going counter-clockwise.
  • When 20 seconds are done, it flashes to turn on all Neopixels to green (one colour) to state that you have comepleted the required time to wash your hands.

📸 Some pics

The CPX I have with and without the case

Adafruit's Circuit Playground Express

Adafruit's Circuit Playground Express

Adafruit's Circuit Playground Express

🎉 Result

20s countdown for washing your hands with Circuit Playground Express

đŸ“Ŋ Here's a video of it working, my hands were sore from clapping while testing so I tapped it loudly on the casing which registers the sound as well. 😊

20s countdown for washing your hands with Circuit Playground Express

ℹī¸ Source code for project

Here's the code on github: https://github.com/whykay/cpx_clap_wash

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