I made a DIY 20 second hand washing timer for COVID-19, to remind you to wash hands for 20s at least. Use the MakePython ESP32 and HC-SR04 sensor.

As the global COVID-19 spread, we should protect ourself not only by gathering less and wearing face mask, but also washing hand more often.
It ’s not effective against viruses if you don’t wash your hands properly.
 
How to wash our hands correctly? We should use hand soap, and washing 20 seconds at least. But how to ensure we have washed for 20s? So I made this 20 Second Hand Washing Timer for COVID-19. You can easily know the time and when time countdown is started and ended, the buzzer will remind you with beeps. This is a very simple project and you can make one by yourself and install it to your sink.
We should protect ourselves well in this special period.

Step 1: Collect the materials

Collect all the components you will use in this project.
I used the following components, for your reference:

1.1 Hardware:
• MakePython ESP32
• Buzzer
• HC-SR04 Ultrasonic Range Measurement Module
• Breadboard
• Some Jump Wires

1.2 Software:
• uPyCraft V1.1

Step 2: Wire the Electronics Components

Next, wire up the electronics components according to my wiring diagram.
HC-SR04----MakePython ESP32
• VCC → 3.3V
• Trig → IO13
• Echo → IO12

Buzzer----MakePython ESP32
• VCC → 3.3V
• O/I →IO15
• GND → GND

Step 3: Program and Test

All the component and circuit is ready, then flash the codes and test. You can download the codehere.

Step 4: Install the Timer to Your Sink

Ok, it is time for washing! Install the timer to your washing sink.
Note:
1. You should adjust the appropriate measuring distance of HC-SR04, according to the condition of your sink.
2. Pls be aware to avoid getting water into your equipment.

Step 5: Complete and Wash Your Hands

There will be beeps sound to remind you the countdown is started and ended. With 1 short beep to start and 3 short beeps when over. Let's wash our hands for 20s and protect ourselves from the coronavirus!

 

Step 6: Other Display Solutions
As the Python is a simple and easy-to-learn programming language, you can program by yourself to realize more creative and beautiful displays for the countdown animation.
 
There's also the  MakePython ESP32 Color LCD which is very interesting with colorful LCD, so those boards are limited only by your imagination! If you need some PCBA customization based on those MakePython IoT solutions, pls contact service@makerfabs.com for help.