Rotary encoder / Wheel encoder

Wheel speed
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Why ?
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Convert a binary information in a speed and with direction knowledged

### Requirement
1 GPIO (Raspberry pi)
2 endstop sensors
1 spring
3 nails
6 screws (2 by endstop and 2 for spring)

### Print parts
**Wheel**
Diameter : 50mm
4 holes so 4 states 0 and 4 states 1 for a complet revolution

** Main part **
To fix spring, wheel and sensors

** Holder **
To fix main part and spring

### What we want to get on the raspberry GPIO
number of