Why does Arduino stop running every 20 seconds?

[Daanii]

I'm a beginner running several Arduino sample programs on a laptop with Vista. They all work fine. But with all of them, the program will stop every 20 seconds or so. Then this happens:
-- the "L" light flashes once
-- the program stops
-- the "RX" light flashes once a second five times
-- the program restarts
-- the "RX" light flashes three more times
-- the sequence repeats

It looks like the Arduino is resetting itself when it receives data from the laptop. I'm using COM7. But I cannot figure out why the laptop would send a reset signal. If I shut the laptop, but leave the Arduino connected, it runs fine without any resets.

Any help appreciated.

[madworm_de]

Well, you must make sure nothing else talks to the serial port. And it's not the laptop's fault, but some piece of code is misbehaving.

Of course the best way to achieve this would be erasing windows altogether and banish it, burn the banned and send the ashes back to redmond - and ask for a refund for sustained pain!

Maybe you have bloat-ware installed, cell phone syncing software... possibilities are endless for evil things. Try disabling all of that.

[charliex]

break it down, does it do it when the bios screen is up? or the f8 choose os screen? this will help determine if its something in windows. try safe mode. try a loopback cable, or null modem to another serial port, or a serial monitor that looks to see if there is anything on the serial.

open hyperterminal or putty to the serial port, if it opens and it still happens its unlikely its a piece of sofware

[Daanii]

cell phone syncing software

You nailed it. I had a cell phone program that was causing the problem. I uninstalled it, and the Arduino works like a charm. Thanks!

[Wish I could do without Windows, but I'm locked in by now. Curse you, Trey!]

[adafruit]

wow, never would have guessed that! good detective work, madworm!

[Kdees]

I had a similar issue with my netbook, blackberry bluetooth pairing, arduino and the windows blue screen of death. same issue.

attach arduino, open serial monitor... mouse would flake... netbook would blue screen, and the final clue:

blackberry would call my old pal Bill

quick trip device manager and disable blutooth... problem solved...

Made me flash back to the days of jumpers labeled "COM", "DMA" and "IRQ"

K

[tytower]

For any others with similar problems I have found that an array overflow problem in your programming frequently causes similar resetting problems