Open Source DIY Face Touch Alert Device

To limit the rapid spread of Coronavirus Covid-19, the CDC and health professionals recommend that we frequently wash hands, and not touch our faces. The spread of the infection can be significantly reduced if each and every one of us can keep from touching our hands to our faces. So to assist in limiting this final stage of transmission, we have developed a simple, practical, and inexpensive device that can alert each of us if we absent-mindedly try to touch our faces. It can be made for just a few dollars. This is an open-source solution and may be used freely.

The earlier we act, the slower the spread, the more lives may be saved. The fastest way to get this device to millions of people across the state, country, and indeed across the world, is to simply share with you how to make this device by yourselves. We share this free of cost. Feel free to improve it with alternative parts more easily available near you.


Here’s How it Works


  1. Reed Switch Normally Open Magnetic Induction Switch for Arduino
  2. CR2032 3V Lithium flat watch battery
  3. Neodymium Disc Magnets – 1.26 inch x 0.08 inch
  4. A strip of Velcro Wrap
  5. CR2032 Horizontal Coin Button battery holder
  6. Vibrating cell phone buzzer – 10x3mm Mini Vibration Motors DC 3V 70mA 12000rpm Flat Coin Button-Type -or- 5V Active Buzzer Electronic Alarm Magnetic Long Continuous Beep for Arduino

Assembly Instructions

The device works by buzzing or beeping as either hand approaches the face. It can be made in less than 5 minutes using a handful (6) of components, each of which costs less than a dollar, a little soldering, and some adhesive tape.

Here’s the schematic.

There are 2 parts. A wrist-mounted magnet which acts as a signaling device, and a sensor circuit located on clothing on the upper chest near the collar. The sensor uses a Reed switch, a buzzer or beeper, a watch battery, and a battery holder. Three electrical solders complete the circuit. Hot glue can be used to insulate and protect the reed switch. Which can be fragile otherwise.

The sensor can be attached to the inside of a shirt using Velcro or tape. The magnet attaches with tape to the wrist strap of Velcro. We can make 2 sets of these, one for each hand. That’s it! Watch the video at the top of the page for step-by-step instructions.


If building the beeping version, the magnets can be located on the wrist, and the sensors in the shirt. Sensors can be attached with a piece of masking tape to inside of shirt.

If building the vibrating/buzzing version, it is better to locate the sensor on wrist, so you can sense the vibration. In that case locate the magnets on the shirt. The magnets can hold their position really well if you use a pair of them, one inside and one outside the shirt.

Consider placing the sensor or magnet inside shirt as shown in picture, as a starting point. Using a hand length below chin and to the side as shown in attached picture. Feel free to vary it from that location till you have early notice.If placing magnets in shirt, additional magnets may be placed to improve coverage. Optional location for such secondary magnets is shown on picture.

Since students from colleges and local schools are off, we have the help of youngsters, who are making some of these devices to hand out to friends, families, and colleagues.

Hardly any QA has gone into this device for the moment. I hope that even if the use of this device only makes a tiny incremental decimal point impact on the spread of the virus, it may be enough to change the exponential rate of community spread enough to play a useful role.


If you have any questions or feedback, please email us at

Caution: Magnets can interfere with the functioning of cardiac devices like defibrillators, ICD’s, pace makers, and other implanted devices. So do not use if you have defibrillators, ICD’s and any other implanted devices.

Disclaimer: Build at your own risk. We are not liable for the success or effectiveness of your device.