Or, how not to wire a relay board to a BOB
Or, Jeff's further adventures into the magical world of electrickery......
So, the boys have sorted me out with the 5v to 4.5v issue. Decision time, do I go out to the workshop in the cold and mill out a suitable holder for the laser, attach switch and cable etc. or do I stay in the warm, forget the switch and cable and use the 5v from my BOB and install this handy relay board I have sitting here.
I chose warmth and relay installation.
Wired it up as the books say, to the BOB's 12v and 5V outputs (both separate) switched on and.....success, green light comes on and I can manually operate the relays, brilliant.
Now I need to wire it into one of the outputs on the bob to operate it. Done. Switch on, FIIIIZZZZZZZZZZ, delay (short), BANG! BOB loses a transistor and a capacitor swells up like a sore thumb.
Board now back with Roy at DIY CNC( a real champ) for fixing and a replacement on it's way back up as a spare.
Thank God I never got around to installing those diodes, probably be missing one small island and half the west coast :p
Anyway I found out two things, I really do know just enough to be dangerous and my tagline is just soooo accurate.
Nothing is foolproof......to a sufficiently talented fool!