This capacitive touch sensor works just like a normal button, but there are no moving parts. The sensor will feel a “press” through the body of the device and will work as a great endpoint for home automation projects.
The sensor also works through non-metallic materials such as plastic, cardboard, plywood, or glass. This feature can be used to create hidden or protected controls, so your dreams of becoming a Scooby Doo villan can finally come true.
Place the module in a sealed case or hide it under the front panel of your device. The sensor can feel a finger approach even through a four-millimeter dielectric layer.
Capacitive sensors can be used for more than just ‘buttons’. For example, they are perfect for controlling the water level in a plastic tub or even an aquarium.
The touch detection system consists of a sensing element, a sensor capacity measuring unit, and a logic circuit that responds to a capacitance change as an object approaches.
As a sensitive element, a conductive circuit is often placed on the front of the module.
The logic is based on the AT42QT1010 microcircuit. It is responsible for the automatic calibration of the sensor. The calibration takes about half a second and is performed immediately after the power is applied to the module. In addition, the chip filters values, compensates for the drift of the capacitive sensor, and also corrects the operation of the device when the temperature and humidity of the surrounding environment change.
Each time the sensor is triggered, a bright red LED lights up. This will help when debugging the project and is useful for creating interactive control panels.
The sensor module is essentially a button. When the button is pressed, the sensor outputs a logical 1, and a 0 when released.
In its simplist version, the module is connected to the control electronics as a button using a 3-pin jumper cable
To do this, use the left group of contacts:
On the right group of contacts, only one pin, M, is used. It switches the operating modes of the module. The remaining two are used to securely fix the module to a Troyka Slot Shield.
Troyka Shield. The most straightforward method. Connect the module to a pin group on Troyka Shield with the 3-pin jumper cable and you’re ready to interface with it from your Arduino.
Troyka Slot Shield. The best choice for quick prototyping. Using slots on the shield, you can get rid of cables. The module will be held securely in place using both pin headers.
Breadboard. For advanced use. Troyka pin headers have 0.1” spacing which is compatible with any breadboard. Simply wire the module like you would do with any IC.
By default, the module operates in powersaving mode. The sensor is polled once every 80 milliseconds. Use this mode if you are worried about power usage (especially if it is running on battery power).
If you need to increase the responsiveness of the interface, connect pin M to the controller and apply a voltage to it. The module will switch to high-speed data processing mode, where the interval will decrease to 10 milliseconds.