Hopefully an easy question — is it possible to upload an arduino sketch to a handful of Arduino units at the same time? If not through the IDE, then perhaps through a shell script or equivalent?
I am programming one prototype board for a project which will end up using upwards of 30 boards, all of which may need software tweaks/re-upload once installed in the gallery space.
Any suggestions?
It can be done with 30 usb adapters / ISP programmers for sure. If you have that many cables/usb hubs etc.
Connecting the boards in parallel to just one is pretty much out of the question, as the communication is not necessarily one-way. There'll be interference.
But what is so bad about doing it one after another? Flashing an ATemga168 with 16kb using an usbtiny just takes a couple of seconds (even less if you disable the flash verification step). BTW, the latest optiboot bootloaders should be quite fast as well running at 115200.
What the IDE uses to upload the code to the arduino is a small command prompt programm called avrdude, this is what I use to program my Arduino:
avrdude -p m328p -c avrisp -P com* -b 57600 -F -U flash:w:your_hex_file.hex
To know your com port just look in the arduino IDE, if its an Duemilanove board the avrisp protocol and the 57600 baud-rate are spot on, to know where your hex file is hold down shift when you press the Verify/Upload button in the IDE.