Arduino Ports Changes with each Upload

I just pulled the Arduino bit out of the box and I was able to follow the first littlbit video, and all was well. I even loaded a few examples from the File/examples in the program. Blink and ReadAnalogVolrage. Again all worked well, but now each and every time I Upload to the Arduino Bit, the Port I am connected to changes. It jumps by 2. By this I mean if I am connected via /dev/cu.usbmodem114. I upload the BareMinimum sketch, It uploads fine, gives me the Done Uploading status. Within a few seconds the status at the bottom of the Sketch Window will change from “Arduino Leonardo on /dev/cu.usbmodem114” to “Arduino Leonardo on /dev/cu.usbmodem115” and then by the time I can select Tools/Port from the menu bar the only selection I have is /dev/cu.usbmodem116. Any Idea how to keep my connection from changing? I am not sure if this is related, but reading up on a few troubleshooting pages I did find someone mention to check the debug rate in the preference file. serial.debug_rate=9600.

I should have mentioned it was the W6 arduino

The COM port number should be the USB port that the Arduino is plugged into. Have you tried a different USB port?

What is your computer and operating system? :computer:

I am using a Mac OS 10.11.

Same thing happens to me Matt. I also use Mac, so I can relate to those crazy port names. Mine seems to alternate between tty.usbmodemfd121 and tty.usbmodenfd131 every other time I disconnect and reconnect the arduino bit. My Uno clones also do that, but my htg Arduino boards do not (Uno R3, and Micro.) I think it’s in how the usb/serial interface works. Now checking the port is a standard part of my standard write-compile-upload cycle.

Hi Matt @LBnewbie, Chris @chris101,

I have exactly the same ! :cry:
After editing an .ino file or uploading, it takes appr. 1 minute and then the com port is disconnected in the IDE. I am using Windows 8.1 (and recently 10) and the latest version of the official IDE.
The com port (including the Arduino Leonardo reference) is still visible in the list under tools-port in the IDE menu, but I must select it every time again before uploading.
Makes me a little crazy ! :scream: :joy_cat:
I think it might be a Windows issue, it started for the first time when I started using 2 different Arduino types.
I own an (old) Duemilanove which worked 100% OK, until I started using the Littlebits Arduino Leonardo.
Then my computer got instant amnesia. and could not hold the com port stable.
I am looking for a solution, but I canot find it. Anywhere…
When disconnecting the Arduino for hardware bit changes, the sequence of reconnecting is very important, else the computer will never see the Arduino.
Disconnecting: 1: USB, 2: Bit power.
Reconnecting: 1: USB, 2: Bit power, check IDE COM port, OK.

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Word.

I think it’s an Atmega 32u4 thing. Something about how it uses usb - my mac thought it was a keyboard, and attempted to set keyboard parameters on it, the first time it saw the littleBits w6 arduino, AND the Arduino Micro board. Both of them may change port designations every time they reconnect. The Uno stays on the same port, and the OSEPP clones (uno r3 and mega2650 r3 plus) are always confused, but I suspect it’s their funky FTDI implementation. The Sparkfun tiny2313 programmer, tiny 85 and tiny 84 never seem to have a problem, no matter which usb port they are hooked to.

So (discounting the osepps) it seems that the boards with the 32u4 are the perpetrators, at least according to my small sampling.

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Hi Chris @chris101,
My elderly friend Arduino Duemilanove ticks with an ATMega328.
Also no problemo.


I still hope someone knows how to fix the com port issue with the Arduino Leonardo W6… :bulb:
@rory_littleBits ?

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I am also working on the same things and facing approximately same issues. I am using Mac. Mine seems to alternate between tty.usbmodemfd121 and tty.usbmodenfd131 every other time I disconnect and reconnect the arduino bit.
My Uno clones also do that, but my htg Arduino boards do
not (Uno R3, and Micro.)
I think it’s in how the usb/serial interface
works.

turnkey pcb

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The change in the port seems to occur at the end of the upload, not with each physical connection from the Arduino Bit and the Mac. Is there some way the Bit can force the port to change? Or maybe it somehow corrupts the connection and the Mac sees the broken connection and creates a new port to reconnect the bit?

This problem was driving me crazy! The same thing randomly happens to me and then randomly goes away. I click upload and then stare at the COM port at the bottom right waiting to see if it will change. The only consistent fix I found is to open the arduino program from the program list (not by clicking on a .ino file) and then open files from the arduino file menu only. No idea why this works or what is going on…

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Hi @ntomlin,
This trick really solves the annoying COM port changes !
Thanks !

I got the same issue. thanks

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From Barcelona, I have the same problem that you have and have you found a solution?
A smile.