Problem with Knob

I was doing the knob example, when the board suddenly gave me this error:

Arduino: 1.8.19 (Windows 10), Board: "Arduino Uno"

Sketch uses 2072 bytes (6%) of program storage space. Maximum is 32256 bytes.

Global variables use 50 bytes (2%) of dynamic memory, leaving 1998 bytes for local variables. Maximum is 2048 bytes.

avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified.

The board was previously working, and I have tried unplugging and replugging it in multiple times. Additionally, the port option is greyed out, and I cannot select anything with it. Any help would be greatly appericiated

It means that the Arduino is not connected to COM3. Check your USB cable.

You did not power the servo through the Arduino? A servo takes much more current than the Arduino can deliver.

Something changed since it was working. Question is what.

Did you change the USB cable?
Did you add/remove a power supply?
Did you add/remove a device such as a motor, relay, etc.?

Remember the state it was in when working and compare it to how it is now. Figure out what changed.

This is suspicious. Define "suddenly". Was it working when you got the error? Did you get the error when you were uploading the sketch?

When is "previously"? Ten minutes ago or last week?

It would probably help if you provide a schematic (NOT a Fritzing thing) or a drawing of how you have everything connected.

closer to ten minutes ago

I attempted to follow the schematic although I did use header wires instead of three separate ones

update: I tried changing data cables and hooking up an additional power source(separately and then both) and nothing changed

the additonal power source was a wall socket connected with an adapter

Was the +5V side of the power source just connected to the servo or also the Arduino? Having two connected (both wires) power supplies could be really bad.

Try to draw a schematic on paper, or just take a picture of your setup (though that is not very easy for us to see).

What schematic? Most of us won't spend the time doing research for you. If you have a schematic, post it. But "following the schematic" doesn't mean that you did, which is why we ask to see a drawing of how you have connected everything.

Be prepared that you may have blown up your Uno.

What is the chip closest to the USB port? 16U2, CH340 or something else?

With everything disconnected except USB, what does Windows device manager think of your board?

PS
I guess you bought a kit; which one? Link please.
If not a kit, link to the board that you bought.

Please provide details of what was connected at the time it failed (including links to them).

Is it possible another program using the serial port ?

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.