MPR121: The MPR121 is a capacitive touch sensor controller,features internal intelligence, include an hardware configurable I2C address, an expended filtering system with debounce, and completely independent electrodes with auto-configuration built in .
Touch Sensor feeler: The Touch Sensor feelers, which was 4 included in Touch Sensor module,can be set in any place you like, to feel your finger's touch or proximity. Notice it must not get in touch with any conductive material.
- Twig - I2C Touch Sensor X1
- Touch Feeler X4