When you do lesson 3, does the code successfully download? Because if you've fried the 5V regulator, it won't. let me guess, lesson 4 had a relay, or some other significant load attached? Knowing that would help.
If you plug in the USB cable, can you upload a program?
Overloading the 5V regulator can destroy it. Even attaching an LED between 5V and GND can do so, if you forget to add the current limiting series resistor.
It looks like that. All helpers don't have that kit in th drawer. If You can provide the schematics for the actual circuit in front of You, it would be great help.
I have powered the board from the computer USB, and also, separately, from a 9V battery. I'm not getting any 5V output no matter what is powering the Arduino.
It looks like that. All helpers don't have that kit in th drawer. If You can provide the schematics for the actual circuit in front of You, it would be great help.
For now, the schematic doesn't matter. I'm just hooking a voltmeter up to +5V and GND and getting only like 1.2 mV. That means the board is fried, I guess?
Is the power circuitry on the ATmega328P that can just be replaced in its socket?
Wrong! It matters a lot unless You want to continue crashing boards. The obvious thing is to find out what ruins the boards, why... and get it to an end.
All power circuitry is on the board, not in the IC.
Wrong! It matters a lot unless You want to continue crashing boards. The obvious thing is to find out what ruins the boards, why... and get it to an end.
I don't need help debugging his circuit, I need help determining what is now wrong with the UNO and can it be fixed.
The board is fried, most likely because of a short circuit or a large load was connected between 5V and GND.
You need specialized equipment to determine and replace the part(s) that were destroyed, and the effort will cost much more than a new Arduino.
The 5V output is intended for at most a couple of small sensors or LEDs. Avoid ALL tutorials that suggest it is OK to power a motor or servo from the 5V output. That is NOT OK.
Do you see the part next to the USB socket with an Arduino sign on it.
Just above the larger red square on the edge of the board on the image of post#7.
That's a fuse.
Connect the Arduino to USB, nothing else.
See if you have 5volt on both sides (be careful not to short the top bit to the metal USB shield).
If you only have 5volt on one side, then check if that part is hot.
Report back.
Leo..
He's running through the Elegoo tutorials that come with the Arduino. All of them are power-safe for the board and the devices supplied with the kit. The current lesson is #3, using code to cycle through the colors of a tri-color LED.
I glanced at it and it seemed pretty simple and correct, so when it wasn't working I assumed he just did something to his board so swapped in mine. Got the same result, so we went back to lesson 2 which is just hardwiring up a single LED and resistor to +5 and ground, which also didn't work. Then pulled out the multimeter and discovered no +5 juice.
Then You should know what destroyed the boards by now.
I hope the reply from @ jremington
makes it clear as mud.
03 Am and late and good night.
The breadboard had already been pulled apart so I have nothing to show you for what might have caused the problem. All I wanted to confirm is that the board is indeed broken if I'm not seeing 5V between +5 and GND and see if it was possible to fix.
This is the lesson schematic. He had 220 Ohm resistors in the circuit.
Edit to add: Son says that when he originally made the circuit it didn't work so he tried "spinning the LED around" (putting it in backwards). This would mean he had hot and ground running through two anodes on the LED (Pin 6 and GND going to annodes on the LED). I don't know if this results in a short or not.
LEDs, like most other electronics, can be destroyed by reversing the power polarity. That could have damaged the Arduino in a cascade of events. Test that LED for approximately zero resistance across the terminals and you have your answer
