Simple RS485 comunication

Hi all!

I’m trying to set up a simple communication system between an arduino uno and a camera to control its PTZ. This type of camera uses RS-485 with the protocol PELCO D.

My question would be if is possible to wire 2 DO directly to camera and generate the data knowing that:
A - B < -0,3V = MARK = OFF = 1
A - B > +0,3V = SPACE = ON = 0

And within the arduino sketch controlling the bit rate and checksum if necessary.

The main purpose of this question is avoiding new hardware like an rs485 shield or similar.

Thx!

For all the external components you would need to do the voltage conversions etc and the arduino code to emulate RS485 it's not worth it. You can get cheap RS485 converters that will save a lot of hassle.

I have make it in 2005 and i thing i have use RS232 (with max232), i thing i have connect the Tx from the PC to Rx+ in camera with common ground on both side (i will try to find my paper to verify).

Also you need to know the Protocol to control the camera. Remember if you want to control the camera with ID 1 on arduino protocol, you will write 0, if cam ID is 5 you will write 4.

Some info about protocol: http://cvs.ru/files/pelco-d.pdf

http://forums.adafruit.com/viewtopic.php?f=25&t=15928&start=15

Good Luck ;)

Thanks for the answers,

I ended up using the software 232analyzer, an usb to rs232 converter and a rs232 to rs485 converter. I'll try to do it with arduino when I have more time...

Greetings!