In a previous blog, I reported that I had designed and manufactured some Printed Circuit Boards that would provide RS232 for the Rasberry Pi. The difficulty was I had no Pi to work with due to the delays in shipping, so I took a chance, and went ahead and manufactured a short run of PCB's in the hope it would work.
Well it does! And here is a picture of my first Pi project sitting in a box, with a DC to DC converter for 12/24 volt vehicles, and my new RS232 expansion board. I connected the DC to DC converter to the expansion board, so there was no need for a PSU to be plugged into mini-usb socket.
You can find the PCB layout here.
The Pi is running the stock Debian distro. No GUI, just SSH access.
As default the RS232 port is configured for shell access to the Pi, but I want to use it for connecting out, in this case to Enfora trackers. To change this, you need to edit the /etc/initab file and comment out the following:
2:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
Further details here:
Then you can use minicom like this:
minicom -b 115200 -o -D /dev/ttyAMA0
The black box at the top of the picture (above) is my Enfora GPS tracker connected to the Pi using an adaptpr cable I made up. The idea is you unplug the Enfora trackers cable that comes from the vehicle, and connect it first to the Pi first, and then the tracker. Simple.
Add a 3G dongle, and a 3G sim card with a fixed IP (which I got from AAISP), and you have a remote controlled RS232 port.