I have an Arduino Uno in a remote location connected to a PC via RS-485 using the Sparkfun RS-485 transceivers. I would love to be able to reprogram the unit via the RS-485 comm link.
But my guess is that this is not supported (Google search popped up nothing). In fact since RS-485 is a simplex connection, it might be downright impossible. The Arduino bootloader would have to know how to switch the transfer direction.
Comments?
Found this thread http://www.arduino.cc/cgi-bin/yabb2/YaB … 1295577254 that gives more credence to my belief that programing over RS-485 is a pipe dream. I will have to introduce a mechanical switch to disable the RS-484 transceiver when programming.
Oh Well. It would have been cool.
I take it you can’t, or don’t want to, run the extra set of wires and so are trying to do full duplex over 1 pair of wires.
RS-422 is cetainly a possibility. It does require 4 conductor cable instead of just two. That does drive the cost up, but it is not out of possibility.
The bigger isssue is that I have not found a source of cheap 422-USB and 422-5V serial break out boards. The Spakfun 485 boards were resonably priced (but do require rework to make them truly 485 capable).
Aaaah I see. What speed USB can an Arduino utilize ? Need it be USB 2.0 ? For what I’d think is cheap $$ you might look at these …
http://www.monoprice.com/products/produ … 1&format=2
Don’t know anything about the above MP devices other than they’re cheap $$s. A little different from extending just the serial port though. What flavor Arduino do you have at the far end (w/ or w/o USB) ?
Those USB over CAT-5 cable extenders are fascinating. I have not seen those before. Will have to consider for the future.
Using an UNO with USB. Your USB extenders would work OK. But I already have the 2 conductor cable run. So the simple solution is if I have to change code (when has that ever happened?) I will just drag a laptop down to the furnace room.
Next project is to monitor my electrical usage at the main breaker panel. For that I may very well try the USB extender.
fll-freak:
I will just drag a laptop down to the furnace room.Next project is to monitor my electrical usage at the main breaker panel. For that I may very well try the USB extender.
That or look into one of those networking over power line adapters.