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Topic: Arduino Uno not detected by pc anymore (Read 32498 times) previous topic - next topic

catartico

Dec 09, 2014, 10:05 pm Last Edit: Dec 11, 2014, 01:43 am by catartico
Hello everyone,

here's my problem:

I purchased an Arduino Starter Kit from Cool Components about three weeks ago. I installed it, everything went fine and have been playing with it until yesterday.

My problem: Today I discovered the Arduino Uno board can't be detected by my laptop anymore. Apparently the COM port has disappeared from Device Manager completely (yes, I've checked if it's under hidden devices, it isn't - as any other COM port, actually).

What happens: When Arduino is plugged in through a USB port it isn't detected by the pc in any way, it doesn't even appear as an "Unknown device" in the Device Manager window, not even after repeatedly scanning for hardware changes. It is completely invisible to the pc, apparently.
Nevertheless, it is powered by the USB port it's plugged in and is executing the last code uploaded just fine (I know because I had assembled it into a thermometer with an lcd display to read the temperature, and it's displaying the actual temperature of the room when plugged in, and responding to variations in temperature such as me heating up the thermosensor with the body heat of my hands)

What I've tried (with no success) after reading about people with similar problems:
- repeatedly unplugging and plugging in the Arduino board;
- tried all USB ports of laptop (I know they work because USB mouse & USB drives are working fine, same for smartphone);
- tried rebooting pc several times;
- tried adding a COM port manually with Arduino LLC drivers (won't work, gives me error code 10, "this device cannot start");
- tried uninstalling the Arduino IDE completely, removing the drivers as well, and then reinstalling, going through the recognition phase as the first time;
- tried plugging the board in while holding the reset button;

What I haven't tried:
Reading here and there, I've seen the problem might be that my pc has disabled serial ports completely (for God knows what reason), and I should check if this is so on the BIOS setup, and eventually re-enable them.
Unfortunately, my BIOS setup is limited and I can't access such options normally. I'd have to mod the BIOS to have it show the hidden sections - which is something I would like to avoid (it would take some further reading too), unless it's my last hope.

So, my question is: is there anything else I can try before resorting to modding the BIOS?
Where is the problem most likely coming from?

Any help will be greatly appreciated.


Further details:
- board is Arduino Uno R3;
- Arduino IDE is version 1.0.6;
- laptop is Acer Aspire TimelineX 5820TG;
- OS is Windows 7 Home Edition;
- haven't installed anything important lately, nor updated Windows;
- I don't have immediate access to other pcs I could try the board on, nor to other boards I could try on my laptop.

ChilliTronix

Download and burn a live ubuntu CD/DVD, burn it, boot from it, go to a terminal, type dmesg. Plug in the Uno and note what changes.

It will establish, without another physical PC, and without reinstalling your existing one, whether the Uno is seen as expected.

catartico

#2
Dec 10, 2014, 03:35 am Last Edit: Dec 10, 2014, 03:39 am by catartico
Download and burn a live ubuntu CD/DVD, burn it, boot from it, go to a terminal, type dmesg. Plug in the Uno and note what changes.

It will establish, without another physical PC, and without reinstalling your existing one, whether the Uno is seen as expected.
Hi, thanks for your answer.

I tried what you suggested, but I must say first I'm no Linux user so I might've got this wrong. Anyway, I did $ dmesg and
Code: [Select]
$ dmesg | grep tty
(which I understand is for serial ports) before and after plugging in the Arduino Uno. I didn't notice any changes, for both commands.

Anyway, there are some (strange) news: Windows installed an update I wasn't aware of when I rebooted, and when I opened the Device Manager and scanned for new hardware again it did detect the board and installed it correctly! Although, it didn't last long: as soon as I tried to upload some code to the Arduino, I discovered the COM port had disappeared again. Subsequent attempts didn't succeed in detecting the board again.

My understanding is that the problem must then lie within the pc. Has anyone had similar problems of COM ports disappearing on their own?

Also, let me mention that this time I rebooted with the board already plugged in - don't know if it matters, but better not leave anything unsaid.

ChilliTronix

Try s system restore to when it last worked. (That is go to the Windows system restore where you can backdate how the system was set up).

On a Linux set up the do dmesg | grep ACM and see if that outputs anything. (The Uno R3 is slightly odd in how it comes up as a com port)

GG20

Hi,

I am very new to this. I have an Arduino UNO R3. I have the same problem mentioned above. I've tried almost all the things mentioned above to fix this problem. One thing that is weird is, the RX TX light stays on sometimes when i connect to my computer. I do not have anything connected to the board. Just trying the get my computer to recognize the connected device. Can anybody think of reasons why this might be happening? It doesn't happen everytime. My computer was recognizing the board one minute and the next it failed and doesn't anymore. Any help will be appreciated. 

ChilliTronix

@GG20, if you read the OPs first post, it contains useful details like operating system, what sort of board, where he bought it from and so on.

You have just said I have the same problem.... It doesn't give anyone trying to help much of a clue.

catartico

Update:

I tried a system restore (to the 2nd of December, when it was certainly still working), as suggested, but it didn't work either, the board still can't be detected. I'll try again with Linux and $ dmesg tomorrow, to see if something happens.

Anyone aware of some diagnostic tools for serial communication on Windows? I want to understand on which side the fault lies, the Arduino Uno or my laptop.

ChilliTronix

You can try the loop back test at the top of the forum....

catartico

- Tried Linux + $ dmesg again (following steps 1-4 of Loop-back test too), nothing happened at all when I plugged in the board. Other peripherals produced events in the log though

- Tried the Loop-back test (which I wasn't aware of) but can't go past step 5, i.e. even when permanently under reset the board isn't detected by the pc.



At this point, I don't know what to think anymore.

ChilliTronix

Are you trying these tests with nothing else connected to the board?

What was the last circuit you had connected to the board?

avr_fred

#10
Dec 13, 2014, 07:17 pm Last Edit: Dec 13, 2014, 07:18 pm by avr_fred
Since Windows does not see the board, have you tried a different USB cable? Or tried using the cable on a different USB device to confirm it works?

The cable is the weakest link in the lot. Granted, it is a gen-u-wine Arduino cable but it still could be defective.

catartico

#11
Dec 15, 2014, 12:32 am Last Edit: Dec 15, 2014, 12:34 am by catartico
Are you trying these tests with nothing else connected to the board?

What was the last circuit you had connected to the board?
I've done the tests in both conditions, with the board hooked up to the above mentioned thermometer-with-lcd circuit* (which should answer your second question) and with all the jumpers removed from the Arduino pins. As for the loop-back test, I've followed the instructions, removed all jumpers and then inserted one from GND to RESET, and one between the RX and TX digital pins.

* it's really just project 11 of the book that came with the starter kit, with the thermosensor in place of the tilt switch

Since Windows does not see the board, have you tried a different USB cable? Or tried using the cable on a different USB device to confirm it works?

The cable is the weakest link in the lot. Granted, it is a gen-u-wine Arduino cable but it still could be defective.
I imagined it could be the cable, but I thought it was an unlikely possibility given how new it is. I don't have the chance to test this cable on a different device but I'll test a different cable in a couple of days, thanks.

catartico

#12
Dec 25, 2014, 01:12 pm Last Edit: Dec 25, 2014, 01:13 pm by catartico
Last update on the problem:

I've finally managed to get hold of someone else's functioning Arduino Uno and a different pc to test mine.

Results: my Arduino Uno can't be detected by the other pc too. On the other hand, my pc detects the functioning Arduino Uno I've borrowed. Thus, the pc is fine, and the board is gone. I'll ask for a replacement soon.

Thanks to everyone who tried to help me!

ChilliTronix

Where did you get the defective one from?

catartico

Where did you get the defective one from?
Hi,

I just saw this, I got it from Cool Components as said in the first post of this thread.


Anyway, I came back here just to report on the fact that

Cool Components refused to replace the faulty Arduino board they sold me
(their reason was the order was "more than two months old" - I emailed them the 17th of January 2014, the order was dispatched the 17th of november 2013; you be the judge on that).

Never buying from them ever again.

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