How to sense objects with the Touch Board
Learn how to sense objects with the Touch Board
The Touch Board‘s capacitive sensors allow you to sense anything conductive. Sensing if a human touch is continuously touching a sensor is straightforward, but if you want to sense whether a conductive object has been placed on the sensor you need to redesign your sensor. When a human touches the sensor, they are forming a connection to the ground because they are standing on the ground. Metallic objects don’t have a connection to ground, so you need to add a ground connection to your design.
In this tutorial, we show you an example design and test it with the Touch Board. To demonstrate the sensor, the Touch Board has the “Touch_MP3” code uploaded to it. The “Touch_MP3” code turns on the LED on the Touch Board when a sensor is triggered.
Step 1 Sensing objects without a ground connection
If you try to sense if an object was placed on a sensor without a connection to ground, you will see that the board has a hard time registering the object. 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.
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 now 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!