Where electronics enthusiasts find answers.
StudioLou wrote: I'm getting about 1.8v across the resister for about 1-1.5 secs, then flipping to -0.4v for 0.5 secs or so, constantly repeating. This is despite rock steady 4.89v across the rails. Not sure what this means.My first impression is that given all the places that are supposed to have 5V do, the wiring is good. That you see some changing voltages across the resistor tells me your code is running and outputting to the correct pin. Your measured times are 50% of the times you've programmed but that's OK. So it appears you're doing everything needed to make the transistor switch and yet it isn't. It's hard to believe that both transistors are bad (possible, just unlikely) so I ask if you tried reversing the orientation of the transistor (not the diode) ? If you have an LED you could put it between the base and emitter of the transistor (remove the transistor) and see if it lights up, on and off, as you've seen for the resistor voltages. This will just visually confirm that the Arduino output pin is doing the right thing.
FYI, I did flip the diode at one point just to see if it made a difference; did not.
One strange thing: The schematic that Chanler provided lists a 10k resistor, as does the schematic that came with my kit:
However, the schematic that Mee_n_Mac provided lists a 2.2k resistor, with everything else being the same:
I'm not sure whether this is important or not. I don't have a 2.2k resistor on hand but I have a stack of 330 Ohm resistors that came with the kit, so I strung 7 of them together to create a rough 2.2k, but circuit still did not work.
StudioLou wrote: How can we make sure this note gets into what gets distributed to new buyers of this kit? Many thanks again from my boy and me!I guess you could put a post summarizing your find on the SIK product page, with a link to this thread. Also e-mail SF tech support and moon them ... errr, let them know as well.
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