I connected the 5v pin to the GND pin on accident for about 30 seconds on my Arduino Nano, and now when I try to use the ide the board doesn’t show up, but the power led is on.
Have I blown it?
Side note, is there a way to use multiple buttons on one pin without the 5v?
Your question is unclear, please explain in other words. Why even 5V for a button?
If you can spare 3 pins then check this out. Shift registers
Thought I might've, just needed to be sure before ordering a new one. I'll take a look at those projects now, thanks.
Have a good one
This depends on which microcontroller and which exact 5V pin
As a general advice be precise in your descriptions.
To make sure that this can't happen again you could connect a 270 Ohm-resistor to the 5V pin
and connect everything else from the other end of the resistor
This resistor acts as a current limiting resistor.
If it happen that you connect the lower end of the 270 Ohm-resistor to ground
the current will be
5V / 270 Ohm = 0.0185 A = 18.5 mA which is uncritical low.
This resistor has a small influence on everything you connect to it.
For sensors the influence is very small.
For LEDs there is a small influence but they will light up.
There is only a big influence on things that you should
connect to the 5V pin like
One option is to use an analog input
best regards Stefan
Chances are high that the microcontroller is burnt.
Chances are, that the LDO is burned. Try to attach 5V on the 5V pin of the arduino, most likely it will work perfectly fine.
LDO TLA (Three Letter Acronym) Low drop output
(voltage)
A voltage-regulator where the minimum diffence between inuptvoltage and outputvoltage can be small
Hi,
A very important question.
How were you powering your UNO, when you shorted the 5V.
Were you using an external power supply through the DC socket?
OR
Were you using the USB power through the USB programming socket.
Do you have a DMM? Digital MultiMeter?
Thanks.. Tom.. 
If the Nano was not powered, it would do no damage at all. But you say it no longer works.
How was it powered?
If powered only by USB, I don't think this could damage the regulator, or the main MCU chip, or the usb-serial chip.
@barshatriplee the high current will not have passed through the microcontroller, so why would it be damaged?
@zwieblum that could only happen if the Nano was powered through Vin pin, could not happen if powered through USB. (As @StefanL38 said, the 78L05 regulator used in the "standard" Nano design is not an LDO.)
I think there is a diode in the Nano which protects the pc/laptop's USB port if you are powering the Nano with some other source at the same time.
Time to look at the Nano's internal schematic...
The diode shown on the right here could have been burned, but if that was true, then the power led, shown on the left, would not light. So it's not that ...
I was using the usb port to power it, nothing else.
Not sure what could be wrong, then.
PC/laptop USB ports normally have a protection circuit that will automatically disconnect if too much power is drawn. Those circuits reset after some time, or maybe when you shut down the pc/laptop.
Because you shorted the 5V and ground pins, the high current would flow though very few components: the USB cable, the USB-mini socket of the Nano, that diode I mentioned, the PCB tracks on the Nano board... that's it. If those things failed, the power led would not light.
Have you been using the same usb cable and port since the accident? Have you used the cable & port for anything else, to test them?
I switched port, cable, and tested using a seperate computer, and it doesn't work with anything.
So it was the cable!
I think you might’ve misread, but it still doesn’t work.
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