Ignoring the fact that there's no resistor on the LED, should this work? Basically, when the push to toggle switch is pressed, the LED should come on. When pushed again, the LED should go off.
A friend designed this for me. I wired everything up as per the diagram (with the exception that instead of an LED, I was going to use a meter to read the voltage) and as soon as I powered it on, the relay started clicking super fast. I removed the power, and it appears to have killed the relay.
Prior to adding the power supply to the output side of the relay, when I would press the button the builtin LED would illuminate, and when pressing the button again, the builtin LED would go off - so the code definitely works.
So, my question is, can the same 9V supply being used to power the Arduino also be used on the output side of the relay to power an LED?
A 9V battery is marginal for powering the board, much less any additional devices. It lacks the current output. Measure the battery voltage when you turn the circuit on - it will probably be less a than 9V.
It is very likely that the 5V output cannot provide enough current for the relay, especially if you really are trying to use a smoke alarm battery to power the setup.
I was going to have the multimeter set on DC voltage just to make sure that the relay was working. As for the power source, the reality is that it will be a 9V 2250mA supply rather than a 9V battery.
OK - I connected everything as per the diagram except for the positive LED and outputs of the relay, and things were working as I would expect (relay was clicking open and closed, builtin LED would turn on and off).
I then added the positive from the 9V supply to the common of the relay and that's when it all went pear shaped (relay clicking really fast, then died).
My plan was to connect a wire to the NO of the relay, and another wire to the negative terminal of the power, with the aim of measuring the output voltage before connecting anytihng in between.
Relay died or Nano or LED? the reason it went too fast is probably because you didn’t use a resistor so introducing bare LED caused Nano to reset, and so it powered down relay and got power back to reboot and activate relay… and so forth. I doubt anything died apart from maybe LED
It was the relay that died. I hadn't even got to the point of installing the LED, just the power from the 9V supply to the Common connection of the relay
You must supply a proper circuit diagram - it sounds like you some how shorted the power supply contacts between n/o and common. ( when the relay picks up , shorts the power supply , then drops out - repeats etc
Draw on a piece on paper with battery plus at the top and 0v at the bottom and everything else in between .
( there are guides for drawing schematics .
Draw from your circuit , not what Fritzing says you should have .
@roybridge Why is VCC going to the common pin on the relay? It shouldn't matter, but I always have a habit of only connecting ground to the common pin of a relay...
Have you removed the 9v source to the relay and tested the relay without a load connected since you "fried" it?
