On Sunday, April 14, 2013 at 8:25:17 PM UTC-6,
brendan...@gmail.com wrote:
On Thursday, April 11, 2013 2:22:29 PM UTC-5, Unknown wrote:
On Fri, 05 Apr 2013 15:34:39 -0700, Brendan Robert wrote:
I was successful at turning a raspberry pi into an AKP (ademco key
protocol) bus sniffer. It's a very rough hack but essentially I used an
optocoupler hooked up to the data line (yellow) of the ademco and on the
other side of the optocoupler I had it output to the GPIO14 (UART RX)
pin. With minimal pain, I was able to set up ser2net and now I can open
a telnet port and read everything on my alarm bus.
Only parts required were wire, breadboard, optocoupler, a few resistors
as needed.
Hack the planet!
-B
Can't you publish the details?
Oh, I don't mind doing so. I originally wanted to make a big article about it for hackaday as I love posting there. But then I realized it might be categorically stupid to announce to the world what kind of alarm system I use in my home.
Suffice to say, the Ademco keybus protocol used in various alarm systems sold by ADT is serial-based. With very minimal voltage conversion (step 12v dc down to 1.5v dc) you can hook up the data (yellow) to the RX pin on the raspberry pi and read the
alarm as a serial device quite easily. This does not allow you to transmit on the alarm bus though because it is a 1 wire protocol with a second wire used to signal bus assertion and other such stuff (it's kind of an odd protocol really)
I used an optocoupler but you could probably also use a MAX or possibly even a straight-forward transistor circuit. My deal with the optocoupler is that I knew that the protocol is low-speed (4800bps, I think) and therefore an optocoupler is a
sufficient choice and provides total isolation between the alarm and the pi.
-B
Like RS232?
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