The AT42QT1010 Capacitive Touch Breakout offers a single capacitive touch button with easy-to-use digital I/O pins. The Atmel AT42QT1010 Charge-Transfer (QT) Sensor is a dedicated, single-button capacitive sense chip. The chip handles monitoring a conductive area for touch. As long as a touch (e.g. from a finger) is detected, the AT42QT1010 keeps the output line high. Otherwise, the line is kept low. It doesn't even have to be a direct touch; it can sense a finger near it — you can even cover the "button" part of this board with a plastic layer and it still will work.
You just need to provide a power source (1.8V to 5V) and Ground for the AT42QT1010 to function. Additionally, a PAD pin is available if you would like to create your own external electrode. The on-board electrode (touch area) is on the opposite side from what's shown in the picture. You can use surface-mount pin headers placed on the solder pads for a totally flush "button" side, or through-hole pin headers.
The output from the AT42QT1010 goes directly to the OUT pin on the board as well as to the transistor on the left side which operates the LED in the center of board. By default, the OUT line and LED lines are connected, which means that on a touch, the on-board LED lights up. You can disconnect the LED by de-soldering the jumper labeled LED Enable. This will stop the LED lighting up when there is a touch, but you can still drive the LED externally using the LED pin on the board.
Two Operating Modes Available On the right side of the board, there is a solder jumper labeled Mode with L and F markers. By default, the center pad and the F pad are connected, which puts the AT42QT1010 in Fast mode. In Fast mode, the chip is more responsive to touch events but draws 200µA to 750µA in normal operation. If you de-solder this jumper and connect the center pad to the L pad, the AT42QT1010 will be in Low-Power mode. In this mode, the chip is slightly less responsive to events but uses only 15µA to 75µA.
Example Usages Here, you can see the sensor working through a 0.125-inch acrylic cover (the LED is on, indicating a touch):
Here, you see how some strips of copper have been used as an external electrode:
Capacitive Touch Module Board Resources
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