The openQCM proximity electronic is designed in order to be an Arduino Micro shield. The proximity electronic mounts a quartz crystal oscillator driver which incorporates an unbuffered inverter plus an inverter into a single device and it is optimized for crystal oscillator applications in a wide range of frequency (eg.: 1-25 MHZ). The openQCM electronics is designed to make use of the oscillator driver in a typical configuration also known as Pierce oscillator circuit.
Furthermore, it is equipped with an I2C temperature sensor in order to better monitoring the temperature dependence of the quartz crystal frequency.
The oscillator driver is optimized to work at 3.3 V supply voltage, ±24 mA output current. These working conditions ensure high frequency stability and low power consumption. Arduino Micro has a 3.3 V supply generated by the on-board regulator, maximum current draw is 50 mA. So the 3.3 V pin is well-suited to power the oscillator driver.
Two clips are embedded to ensure a simple and instantaneous electrical connection of the quartz crystal sensor.