The Field Field Kit

During the school's STEAM summer camp, we played with a radio, a reflector and the Field Field Kit.

The radio transmits at around 440 MHz (wavelength 70 cm band). The reflector acts as a mirror and the inteference appears to be constructive or destructive depending  the distance from the antenna (we didn't measure the distance). When the reflector is very close to the antenna, the transferred power falls drastically, although one would expect the interference to be constructive: it's as if the reflector absorbs the signal.

We have now added a monochrome OLED screen (SSD1306) to the Uno, simply plugging the I2C pins directly into the board and bending SSD1306's the GND and VCC pins and connecting them with wires. The setup is powered with 4 AA batteries via the jack.

This allows a much more versatile use of the device since it can illustrate the signal dynamics at different signal levels. The previous version only used the built-in LED and only reacted when the input was above a hard-coded signal threshold. That was for instance useful to find electrical wires in the wall.

Initial experiments with the new functionality and a hand-held radio emitter showed that the strength of the EM field depends on:

 * distance

 * orientation of the antenna

 * whether there is reflecting material around

 * whether there is absorbing material around