Thanks, this was helpful.
In my case I had to add 0.5 though...

BTW would expr be slower?

Hi, I am just starting with arduino, and still not very experienced in PD.
I have found tons of great info around here, thanks for that.

For me, everything works up to a point:
* I successfully upload the Firmata
* the output example in Processing works, I am able to turn pin 13 on and off
* in PD I open the correct port ("[comport] opened serial line device 3 (/dev/ttyUSB0)")
however, I have not been able to get any communication with the arduino in PD using Hans-Christoph Steiner's [arduino] - either turn pin 13 on/off or get firmware information. The numerical commands sent to [comport] seem correct, e.g. 249 for version information, etc.

So, the only place it seems possible to be going wrong is either [comport] or after that, along the line. As I said, it works with the same port from Processing, and at the same rate - 115200
"get_baud_ratebits: 115200.000000
set_baudrate baudbits: 4098 /***(what does this second line mean?)
[comport] opened serial line device 3 (/dev/ttyUSB0)"

I am running Ubuntu Intrepid, latest versions of Pd-extended, Arduino IDE, Firmata. The board is old though, "Arduino NG or older w/ ATmega8" but I guess this doesn't matter if the above mentioned things work.

I still have to test it for input, but I have to pick up some sensors from the shop.
If [arduino] does not work out I may try Messenger, but it really seemed quite good for what I am trying to do (drums with input from piezo elements).

edit:
This *may* have been due to a bad Arduino board, because I am now unable to transfer any sketches to it. Surprisingly though the Processing example still works (Firmata is left on the board from the time transfers worked)