Basic problem from reading port /ttyACM0

Projects Programming
1

First of all, hello !!!

As i'm quite a newbee in this magic world i'm trying to get some answer to some -probably kind of- easy problems i met.

Right now i was trying to read pusle (for each liter) of a water-meter with an Arduino (it was working pretty well) and to send it to /dev/ttyACM0 (through USB serial) on my Raspberry (Raspbian) where it should be read and analysed by a Python script... and it worked for some times...

But something weird happened...
First of all, the code was working perfectly well (this might probably mean "enough well", but i'm so entusiastic) and sending it on /dev/ttyACM0..
Suddenly (i might have changed the baud rate and then came back to the original 9800) it couldn't recognize ttyACM0... so i coulnd't read with my Python script or open the IDE console and neither upload my little code to the arduino...
so i rebooted the arduino and the the IDE arduino was proposing in "tools>port" was ttyACM1... so i selected it, as i haven't any other choices...
And the same problem was there... it didn't recognize the /dev/ttyACM1 even if it was in the tools>port menu..
I did it also for the next which was possible ttyACM2... and the same problem appeared...

Do you ever have met the same problem?
I really feel i didn't change anything so i really have no idea where to look at ?
I was also wondering it the raspebrry wasn't "to hot" ?

2

I presume you are using some form of Linux?

I think this happens when the serial port isn't closed by one of the applications and then something tries to open it.

Have you given yourself the correct permissions to use the serial port?

Does the problem go away if you reboot the PC? If so it probably confirms my suspicion.

...R

3

In fact i use Linux (Raspbian).

Even when i turned off everything, when i turn it off again my ttyACM0 can be selected in Tools -- > Ports, but when i compile and try to uppload it the same probem appears again and again...

Below you can see what i get :

I feel really hopeless about this subject as i was really thinking it should work this morning when i turned on everything... and it didn't...
Does the problem might come from Raspbian ?

Capture pb.jpg
Capture pb.jpg521×751 161 KB

4

Oups, i realizaed this post might already be treated (Error opening serial port '/dev/ttyUSBx' on Ubuntu - Troubleshooting - Arduino Forum). I'll look after that...

5

Are you powering the Arduino from the Raspberry, or using its own power cable?

You really do NOT want to try and power anything more than a keyboard from the Raspberry as the USB chip on there is incredibly weak and can't provide much in the way of power. One of the many faults that happened with my first Pi was that the USB chip went into meltdown and could no longer communicate with anything - not nice.