I just connected this endstop switch to an arduino nano that I had laying around. Gnd was connected to gnd, +5v was connected to the +5v pin and the signal was connected to D4. When I plugged the mini in I saw an error on my computer screen mentioning that the USB port was drawing too much current. I unplugged it immediately, after I unplugged it I noticed a plume of smoke wafting away from the mini.
What did I do wrong?
Thanks,
Loren
Pretty sure you shorted 5V to ground somehow. Did you check the pinout of the switch with a
multimeter? Should always check these things to make certain, its a quick and easy thing to do.
That link is not the datasheet for a particular switch, so its not telling us what switch you have.
And where did you have your resistor?
You must have shorted out the 5volt rail (to ground).
That will fry the reverse protection diode on the Nano.
No way we can tell without seeing clear pictures of the wiring and the switch.
A quick check with a DMM would be wise before you use it again.
Leo..
Thanks for all of the comments. This morning I took a quick look at the switch.
R1 looks to be a current limiting resistor for the LED. I tried measuring the R2 but wasn't able to get a solid reading I'm guessing because of the cap that's next to it. I did find a picture of the same style of switch where R2 had 103 listed on top. That would indicate that R2 is a 10k resistor correct?
When I measure resistance between the +5v and signal without the switch pushed no reading (obviously). When I measure resistance between +5v and signal and the switch is pushed the meter reads 10k ohms, as you would expect. Great! But when I measure resistance between +5v and ground there is almost a short (1.25 ohms). How would this work in my 3d printer then without frying the arduino mega?
I'm really confused.
After thinking about it, would feeding the +5 from a digital pin have the same effect on a nano?
No, plugging 5V into an IO pin will most likely kill the IO pin side before frying the voltage regulator, which is probably where your smoke came from.
There's very little reason to have bought that switch module. Those microswitches themselves are a few cents, the Arduino has internal pullup resistors, all you got was a waste of space and a little led.
Show pics of both sides of your 'Nano'.
Hi,
Tom... 
Here are the photos:
How is what I did different than the end stop switches shown in this schematic:
Wawa:
That will fry the reverse protection diode on the Nano.
Can that diode be replaced?
Yeah, they come with a new NANO.
Did it come with headers that you removed? Any reason you're not using headers? PCB looks thin on the edges, maybe during your soldering massacre things shorted somewhere.
Get a new Nano, try again.
For the learning experience, you can remove that fried diode (it's next to the usb plug on the underside and has that bump on it from being fried) and just solder bridge the contacts. The Nano may still work, as long as you are certain not to wire it up wrong and give it a reliable 5V source into the 5V pin.
I do have another nano, I'll put connectors on the other stuff and try again. But my question remains. Based on the schematic referenced above how do the end stop switches that I purchased work with an Arduino mega but not a nano?
Thanks,
Loren
The question doesn't remain. You're blaming the switch when it's most likely whatever you did to the Nano.
