keyboard frozen under Ubuntu


I am not sure if you've experienced the same problem when using Arduino IDE under ubuntu.

When I am editing a sketch in Arduino IDE, it seems the program is not responding to what I type from my keyboard.

But the Arduino IDE is not frozen, as I can use my mouse to click the menu bar, and eg save the file.

This happens randomly, sometimes it never happens for a day, but sometimes this " no response" happens every 5 to 10 minutes.

What I can do is to use the mouse and save current sketch, and restart the IDE again.

I am using latest Arduino 0017 I found same problem in Ubuntu 09.04 and 09.10

Cheers Joseph

Hi, which JavaRunTime is installed on your system? ('java -version' in a console will tell you)

If its OpenJDK i suggest you install package 'sun-java-6-jre' .


Arduino 18 is now available on beta and may solve your issue…



Here's info I got from the Terminal :

Experimental: JNI_OnLoad called.

Stable Library

Native lib Version = RXTX-2.1-7 Java lib Version = RXTX-2.1-7

strangely, I also checked from System Monitor, under Process Name java, Status: Sleeping ( which is same status when I can do some typing ) %CPU : 0 Nice: 0 Memory:43.0 MiB Channel is "futex_wait_queue_me


The other strange thing is that the keyboard is back to working again after some time ( maybe a few minutes, or half an hour?)


Now I found a quick fix to this problem.

When you start up the Arduino IDE, you open two sketches at the same time. Eg, one sketch is the one you are actually working on, and the other one is just a dummy sketch.

I found that such "keyboard frozen" happens in one of the 2 opened sketches. So eg if I found the sketch I am working on is frozen, I go to the dummy sketch and do some typing, and actually that window is responding, and you know that you can use your keyboard again.

Next, you use your mouse and go back to your working sketch. Guess what? you found you can type again!! ;)

I think the problem is due to "Active window" sensing between the 2 opened windows.

The IDE thinks that I am working on the other window ( eg dummy sketch) that I am not actually using. So to gain back the control of my keyboard, I go to that dummy sketch, type something, and let the IDE wakes up / ready to receive data from my keyboard, then I switch back to the working sketch, and continue my work

When I have time, I will try on the 0018 beta, and see if this is solved or not



Hi folks,

I just tested on with Arduino 0018

I encounter the same "keyboard frozen" problem.

So I use the sam trick to open an extra "dummy" sketch, and jump back to the original sketch.

This help to get back the focus from Arduino IDE

Cheers Joseph