Hi, first post here, so I hope this isn’t an extremely dumb question.
I recently got an Arduino Uno, and a Vilros Ultimate Starter Kit, and I’ve been working through the example circuits/sketches. Most of the sketches, including for Circuit #11, say they were written by Sparkfun Electronics, so I hope this is a good place to ask a question.
#11 is the first circuit of the kit that hasn’t worked as expected, and that I can’t figure out why. This one uses an Arduino output to drive a transistor, which in turn drives the relay coil. There are two LEDs, a red that is connected to the NC lead of the relay, and a yellow that is connected to the NO lead of the relay.
The sketch is very simple. Sets the output high (energizing the relay coil), delays 1 second, sets output low, delays 1 second. Loop forever.
So you expect that the red LED will light for one second, then the yellow LED for one second, etc. Except, on my circuit, the red LED lights, then it goes dimmer, then brighter, and so on. The yellow LED never lights.
I can hear the relay clicking if I get close enough. If I reverse the leads to the LEDs, the yellow lights, dims, lights, etc. Rechecked all the connections. Just not sure what’s wrong.
Thanks for any help!