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zoombini · 14-04-2005, 09:42

Hmm, hazarding a guess...

Looking at Maplins, 9V relays are quite hard to come by.

Maybe if you cannot use 12v then you will have to stick to 5v ones & stick 6 off 1A general purpose diodes (1N4002 etc) in the top +vline, the bit between junctions directly above the common pins of A2 & B1 relay contacts.
This would drop the relay control side to 5v while leaving 9v for the motor side.

The relays can then be like these or may have to be bigger depending upon the current drain of the motors in the R/C car.

The switches appear to be simple single pole "push to make" ones like these.

However, relays can use a lot of current, be quite big & expensive.
A circuit that uses transitors/FET's may be of better use.
This one that is from in the Cybot project ( currently in the loft) may be better. Adding switches or better still PIC control would be required.

Try seaching for robot control sites for further ideas.
here and here are other examples.

14-04-2005, 09:42	#16
zoombini cf.mega poster Join Date: Jun 2003 Location: England Services: I no longer receive cable services, I blame the inept accounts dept for that. Posts: 3,732	Re: question for the electrical engineers Hmm, hazarding a guess... Looking at Maplins, 9V relays are quite hard to come by. Maybe if you cannot use 12v then you will have to stick to 5v ones & stick 6 off 1A general purpose diodes (1N4002 etc) in the top +vline, the bit between junctions directly above the common pins of A2 & B1 relay contacts. This would drop the relay control side to 5v while leaving 9v for the motor side. The relays can then be like these or may have to be bigger depending upon the current drain of the motors in the R/C car. The switches appear to be simple single pole "push to make" ones like these. However, relays can use a lot of current, be quite big & expensive. A circuit that uses transitors/FET's may be of better use. This one that is from in the Cybot project ( currently in the loft) may be better. Adding switches or better still PIC control would be required. Try seaching for robot control sites for further ideas. here and here are other examples. __________________ Not really visiting CF much these days.... If you need me, PM me.