How To Fade An LED Using Touchless Sensing And The Touch Board

How To Fade An LED Using Touchless Sensing And The Touch Board

How to use the Touch Board's proximity sensors to control the brightness of an LED

In addition to touch, the Touch Board can also detect proximity. With the proximity function of the board you can trigger an MP3 from distance, or you can fade an LED on and off by approaching the sensor with your hand. In this tutorial we’re going to show you how to fade an LED on with proximity and the Touch Board, creating a dimmer effect.

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You will need:

  • 1 x Touch Board
  • 1 x USB Micro B to USB A or USB C (depending on your computer's USB port type)
  • 1 x Computer running Mac OS, Windows, or Linux
  • Printed Sensors
  • Headers
  • LED
  • Jumper wires
  • 270Ω resistor
  • crocodile clip

Step 1 Set-up the Touch Board

First, you need to set up your Touch Board. If you haven’t done this yet, you can do so by following this set-up tutorial.

You then need to upload the “Prox_LED” code. Select the sketch from the Sketchbook and hit upload.

Step 2 Approach electrode E0

When you now approach E0 with your finger, you should see that the LED marked with an “L” on the Touch Board fades on and off.

Step 3 Using 5mm LEDs

You can also use 5mm LEDs with the Touch Board. If you haven’t used them with the Touch Board before, have a look at our LED and Touch Board tutorial.

Connect an LED to pin 13, but don’t forget to include a resistor! When you now turn the Touch Board back on and approach E0 with your finger, the LED will fade on and off.

Step 4 Add Printed Sensors

Just approaching an electrode with a finger can be a bit tricky as it’s quite small. You can make it easier by increasing the sensor size using a Printed Sensor. Simply attach a Printed Sensor to electrode E0, by using some crocodile clips. When you now turn the board back on and approach the sensor with your hand, the LED will fade on and off more smoothly.

Step 5 Adjusting volume with proximity

We have a similar code “prox_volume”, which will allow you to adjust the volume when you approach E0. Simply upload this sketch to your Touch Board and play a track by touching an electrode from E1 to E11. If you now approach E0, this will decrease the volume.