I have now succeeded in getting my ComGSM substitute to work. I’m grateful for the suggestions and advice I’ve received.
I have come to the conclusion that the TC35 board I originally bought just won’t work in this situation. I can’t really come up with a good reason for why, but as described in previous posts it doesn’t function correctly when connected to the panel. I think it does now work though so maybe I’ll find a use for it in another project.
I have now connected up the SIM800L module along with the voltage regulator and it worked perfectly first time. It is clear that this is a much more up-to-date module, being a fraction of the size of the TC35 one. It also uses a micro-SIM rather than a full size one which is handy. It is possible to insert the SIM the wrong way round though, which caused me some consternation until I realised it.
After some rough testing I’ve now permanently installed the two boards inside the metal casing, with the antenna fixed to the outside. I’m very pleased with the end result which is very ‘stealthy’ and actually to my mind is much neater than the official Texecom unit.
Here is the whole cabinet, with the SIM800 module next to the main board on the right and the regular board hidden behind the bundle of sensor cables (note the incredibly bright green LED!). The antenna is on the top with the black cable just about visible.
These show the detail of the antenna, regulator and SIM800 board.
I then configured the panel with COM1 as the GSM module, and much to my relief after restarting the panel saw this in the ‘Online Status and Control’ window in Wintex:
The bottom right shows that GSM signal strength and bit error rate as both being normal. The ‘online’ doesn’t mean anything as it says this even when nothing is connected.
As usual there is a huge amount of configuration you can do, and this is contained in the manual for the real GSM unit. It is wise to tone down the notifications, since as default you will get an SMS message every time the panel is armed or disarmed and it seems to store a backlog. When I first got it working I got loads and loads of text messages for the last week or so.
I need to properly test that it will send me a text if the alarm goes off but I’m sure it will work. You can also send various commands using SMS, but the issue I have with this is that you need to prefix them all with your code which means that if anyone got your phone they could easily read it out. However this is in reality rather unlikely.
I use giffgaff for the mobile phone service, mostly because I use them for all the other phones in our house as well. I’ve found them to be very good and I’d definitely recommend them.
So I am happy that finally this project is completed and at very little cost. I’ve developed the capability of the alarm and it does now stand alone in the event of a power failure etc and can get to the outside world without relying on the Internet.
So… what’s next? Well, I am getting interested again in intelligent heating control systems and have recently ordered some new bits, so will post about this when I have some time. In the mean time, if this interests you I’d thoroughly recommend Andy Carter’s blog on the subject which I’ve found a mine of useful information.