Allow to control door opening via Raspberry Pi

Based on the ULN2830A opto and relays you can plug the RPi directly on it without any fear of seeing your RPi have a shock...

- 2 doors can be opened
- recieve bell
- 3 programmable push buttons (open each doors or both, for example)

- possible external bell triggering

- possible internal buzzer

- RGB led for status

- led for quiet alarm on bell ring