sensor for continous motion

hi everyone,
my design is a continuous motion device (lifting up and down) with the range of motion of 0°- 130° , with adjustable angle range of ±5° , meaning that if we set 30°, the moving base will move from 0° to 30°, then change the direction of lifting. so i need a sensor that enable me to adjust its initial location according to the favour angle range .
the size of the moving base is basically similar with the size of the lower arm.the mechanical design is basically consist of a stationary base and a moving base.
my rough idea is to fix the sensor at the pivot. the favour angle range is set by adjusting the two movable "needle sensor" initially, my problem is what type of sensor can i used to detect if the moving base have reached the angle that i set previously

engkeat said:

my rough idea is to fix the sensor at the pivot. what type of sensor can i used to detect if the moving base have reached the angle that i set previously

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**broken link removed**

You can make your own coder based on the "Gilham Code".

Gilham Coded transmission is used for altitude information of aircraft equipped with a transponder.

The Gilham Code is written on a rotary disk with concentric dark (black) and transparent rings, each ring valid for one bit. E.g. transmitting four bits the code is written of four rings.

Altiude encoding is done using 12 bits.