3/8 RCX Output multiplexer

This home-build device controls 8 Fisher-Technik solenoid valves  from 3 ports.

This is an " easy to build " output multiplexer, for first time in my life I've buid an electric circuit. Definitely LEGO is a good way to learn science.

How does it work ?

F-T solenoid valve is an electric to pneumatic controler , as a LEGO pneumatic switch it controls air-flow in pneumatic circuit. 

A display on top of the multiplexer allows to control which of the 8 outputs are activated.

I develop it  to pilot my futur 6 legged pneumatic walker.



What do you need ?

6 diodes (AN 4002)
6 relays (2 RT,  I used 6V ones but 9V should be better)
8 numeric displays
8 resistors for numeric displays

Resistors depends on how many leds are activated on each numeric display :
 
1 : 2leds  R1=225 ohm    5 : 5leds R5= 90  ohm  
2 : 5leds  R2=  90 ohm    6 : 6leds R6= 75  ohm
3 : 5leds  R3=  90 ohm    7 : 3leds R7=150 ohm
4 : 4leds  R4=112 ohm    8 : 7leds R8= 64  ohm