I finished the proximity sensor, it was a rather long and delicate job (it took at least 4-5 hours).
The job was to somehow fix a set of thin wires like the ones I used for the small sensors, behind each line engraved on the panel.
At first I thought to glue the wires, but despite a very solid fixing, I realized immediately that using any kind of glue without ruining the engraving was almost impossible, so I tried another method: I used very thin pieces (thin as the engraved lines) of transparent tape, which hold in place the thin metal wire behind each engraving line.
The pieces of tape were less dangerous than the glue, but it took a lot of time to fix them all!
Anyway these are the pics of the job.
The first try with the glue and a needle:
Here I glue the big wire that connects the circuit with all the thin wires of the sensor:
Here I am fixing the thin wires with little pieces of transparent tape, behind each engraving line:
This is the result, as seen from the inside of the case:
And this is the result seen from the outside (from the outside, the thin wires behind each engraved line are almost invisible, so it seems that the sensor is the engraving 😀 ):
Finally I soldered the big wire to a connector for the circuit: