As far as I could verify, there is no electrostatic field sensor for Arduino with an affordable price and miniaturized size. However, I can't imagine a Tricorder without a sensor of this type. Therefore, I decided that I should build a sensor that was small and efficient at detecting electrostatic fields. This doesn't seem very simple. My first attempt was a simple circuit with 3 BC547 npn transistors in cascade. I used this on several prototypes including this last one. The result is not remotely satisfactory as this circuit is good for detecting moving charges and not electrostatic fields. So I recently discovered a circuit that has been replicated by several makers and seems to work very well for electrostatic fields. The original circuit can be found at the following link;   "" by Thomas Kim.
The great difficulty was building this circuit on a printed circuit board in a completely miniaturized way. Obviously it took several attempts with circuit boards made using homemade techniques. However, a professional circuit board with good certification and quality control was required. I am very grateful to PCBWay for kindly offering to manufacture a small professional board. The quality of PCBWay's work is undeniable and the result was very good as you can see in the photos. After assembly, the tests showed excellent results as you can see in the videos. You will see that these tests were not done with the tricorder but rather in isolation with a TTGO board separately. In the coming weeks I intend to install the sensor on the tricorder and carry out more detailed tests.