In the initial prototype, the bare reed switch (its enclosure being made of glass!) was just taped to the frame next to where the magnet passes; fortunately there was not much rain or mud, since this 'solution' would have fallen apart pretty fast. The switch was soldered directly to the cable harness, with no possibility of disconnection. This is now history.

I am now using a factory-sealed sensor and I crimped an IP67-compliant connector to ease maintenance.

(Disclaimer: this project is not being sponsored by EDAC in any way :)The mounting of the sensor has also been greatly improved. A 3D-printed spacer now delimits the position of the sensor with respect to the bicycle frame. In retrospect, a rigid spacer was not a very good engineering solution, because it does not provide flexibility in fine-tuning the sensor head positioning at mounting time. But, for the time being, it will do.

More news coming soon!