Project tutorial
touchlessTimer

touchlessTimer © GPL3+

Sealed, 20 second countdown timer triggered by the wave of your hand. Aluminum foil is used as a rudimentary proximity sensor. #Arduino

  • 1,246 views
  • 4 comments
  • 11 respects

Components and supplies

Necessary tools and machines

Scissors

Apps and online services

About this project

This project is inspired by the covid-19 outbreak of 2020. There are a plethora of countdown timers out there, and I thought I'd throw my hat in the ring as well. This countdown timer utilizes a 4x6 inch rectangle of aluminum foil as a capacitive proximity sensor to sense the wave of a hand to trigger a 20 second countdown timer.

To build the touchlessTimer, collect materials in the BOM.

BOM:

  • 1 Arduino Uno
  • 1 Solderless Breadboard
  • 1 3461AS 4 character 7 segment display
  • 4 220Ω Resistors
  • 4 1MΩ Resistors
  • 16 Jumper Wires
  • 1 4" x 6" piece of aluminum foil
  • 2 1" strips of scotch, electrical, or tap


Assembly Steps:

  • Cut out a 4"x6" sheet of aluminum foil
  • Tape 1 end of a jumper wire to the aluminum foil sheet. (we'll connect the other end to the breadboard later)
  • Install the seven segment display onto the breadboard. (I chose the left-hand side of the breadboard to allow room for placing the resistors later. Make sure to orient the seven segment display with the decimal points at the bottom, and make sure the two rows of pins straddle the middle channel of the breadboard so each pin has it's own row on breadboard.)
  • Wire the seven segment display according to the wiring diagram. Note the 220Ω resistors are for wiring the seven segment display, and the 1 MΩ resistors are for the capacitive sensor.
  • Connect the 4 1MΩ resistors in series on the breadboard. If you have larger value resistors availalbe, it is okay to use those instead of the multiple smaller resistors. 1MΩ is the largest value I had on hand. We just want to make a resistance that is at least 4MΩ, and not higher than 10MΩ.
  • Connect the series resistors to the uno like is shown in the circuit diagram.
  • On the pin 2 side of the series resistors, connect the jumper wire that is coming off the aluminum foil.
  • connect the jumper wire between pin 5 and the RESET pin of the arduino.
  • upload the code to the Arduino and test your countdown timer!





Code

Schematics

touchlessTimer Schematic
This is a fritzing diagram that represents the touchlessTimer's circuitry. Some errata: The seven segment display I selected for the project only has 12 pins, but the most similar display i could find in fritzing had more pins.

The antenna shown in the diagram is merely a representation on the 4x6" aluminum foil sheet.
Touchless handwashing timer vlqbdnoimf
Basic Format of Timer
This photo shows the touchlessTimer in it's most basic form. At this stage the function is all there, just the form is missing. Once tested and verified, I suggest mounting the system within a sealed enclosure to ward off splashes during hand washing.
Dsc03301 ce3e2vn2f1

Comments

Similar projects you might like

Touch Controlled Light Using Arduino

Project tutorial by Amal Mathew

  • 15,568 views
  • 5 comments
  • 13 respects

Smart Disinfection and Sanitation Tunnel

Project tutorial by Yash Nayak

  • 11,121 views
  • 16 comments
  • 44 respects

Hands-Free Soap, Water and Paper Towel Dispenser

Project in progress by Samuel Adranyi

  • 2,012 views
  • 1 comment
  • 14 respects

Arduino Game By LCD

Project tutorial by Mohammed Magdy

  • 69,217 views
  • 70 comments
  • 216 respects

touch sensor

Project tutorial by tech guy

  • 25,056 views
  • 4 comments
  • 12 respects

Automatic Watering System

Project tutorial by Manson Hau

  • 14,521 views
  • 11 comments
  • 56 respects
Add projectSign up / Login