- Joined Feb 27, 2019
I made this circuit for controlling a bunch of haunted house type effects. I simply pulled the circuit boards out of some cheap RC cars, removed the motors, and replaced them with the circuit above. The only other change was to replace the 3XAA battery holder from the cars, with a single 18650. Power for the effects comes from battery packs of 2 or 4 18640 batteries, and the relays have 3v coils and 2A contact current max.
At the time I made these, I had a really hard time finding relays with 3v coils or less, and never found anything with more than 2A contact current. now, I look on Ebay, and see dozens of listings for cheap relays with 10A contacts and 3v coils...dunno what changed there. But #1 Would it be better to use transistors, rather than relays? The noise of the clicking isn't really an issue, but I suppose it potentially could be. The main problem was that, after a short period, the relays would become intermittent and everything would get messed up as the batteries drained to where they could no longer operate the relays. That's why I switched to an 18650 I haven't tested, but it should be more than enough life for what I need, considering that the AAs weren't too far off.
So then I guess the real question is about the little circuit I made to operate a different relay (or none), depending on which way the current formerly meant for the motor, is flowing. Is there a better way? A more efficient way? Did I make some glaring mistake? I never got the idea from anywhere, it just made sense to me to do it that way, but I have virtually no experience in electronics
Edit: One sec. Can't find a free image hosting site that works here