For quite a while I’ve wanted to have a go to at serial rs485 comms so with the introduction of the pic 16f628 I now had no excuse. With a small mod I was able to use my I/O board for both master and slave. I had toggle switches on the master and leds on the slave. Eventually got it working using a simple 6 bytes protocol as follows.
Sync, addr,cmd,node,dur,chksum.To help with debugging I made use of my spare video chips and pic, wrote some code and now I can capture data send on the RS485 comms. The capture software is still a bit buggy but good enough to use.
Current project is a Front door intercom monitor. I recently installed a door intercom. The intercom (Panacom) has a data line which Im going to monitor the data stream. When a station call button is pressed it sends data to the master to indicate its active. I will decode the data and if the press came from the front door I will operate a relay which is connected to HomeVision which will hopefully switch my tv to the video channel and select the front door camera. At the moment I could have used a triple 5 timer but I am going to add another station soon so decided to use a pic instead.
Two future projects I hope to do are
1:Make a home brew ir tx/rx unit to interface to HomeVision until I can afford an expansion board.
2:Make a camera selector interface for HomeVision. Previous