How To Sense The Presence Of Objects With The Touch Board

How To Sense The Presence Of Objects With The Touch Board

Create new levels of interactivity in your project with object detection

The Touch Board's capacitive sensors allow you to sense anything conductive. We designed both the Touch Board to detect the touch and proximity of someone's hand. But these boards can do even more. For instance, you can detect whether a conductive object is placed on a sensor. This function is a useful way to add a new dimension of interactivity to your project. But to do this, you need to redesign your sensor. When a human touches the sensor, they are forming a connection to "ground" because they are standing on the ground. As you will see in this tutorial, small metallic objects don't have a ground connection, so you need to add one to your design.

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You will need:

  • 1 x Touch Board
  • Electric Paint 10ml, 50ml or 1l
  • 1 x USB Micro B to USB A or USB C (depending on your computer's USB port type)
  • Computer or USB power supply
  • Small metallic objects to test

Step 1 Sensing objects without a ground connection

The Touch Board struggles to detect objects not connected to ground. As you can see in the video, the LED flashes only when the key is placed on the sensor, and the key is in contact with the hand. When the hand releases the key, the board can't sense the key anymore. Our goal is to help the Touch Board detect the key, even when no hand is present

Step 2 Add a ground connection to the sensor

The Touch Board has a ground connection in the lower corner, so you can paint a connection to ground with Electric Paint. The ground connection needs to be next to the sensor so that when you place the object onto the sensor, it bridges the sensor with ground. In the video, you can see that when the key is placed on the sensor, the light remains on, which means the Touch Board is registering that the sensor is still touched.

Step 3 Next steps

You can use this method in your next project, where the user has to place objects on the sensor to play a sound or to turn on a light!