Reverse Engineering a Hunter PRO-C 300?

[RKMason]

Hi, I have an older (2009 vintage) operating Hunter PRO-C 300 (10 circuit max) sprinkler controller. My interest is to replace the control/display panel section of this controller with a DIY SIP installation to add wifi accessibility and more intelligent realtime weather adaptability. After a quick inspection of my Hunter system I'm wondering if it might be possible to utilize the valve driver section of this commercial controller combined with a near-standard SIP control system build. To determine if this idea has any merit I think I need to reverse engineer how Hunter controls their valve driver modules.  The obvious place to do this is at the 11pin flat cable coming off the controller board and over to the valve drivers.

Since my system is still operational it limits how risky I can get with it doing the reverse engineering, so I thought I would ask whether anyone here has already done anything like this.  My controller is a very low-end but quite common Hunter home system. From my visual inspection, it appears that the individual valve drivers may be operated directly from mpu i/o pins.  Inspection of the 11pin flat cable signals during circuit operation should tell the tale.

[astrogerard]

This should definitely be possible but I doubt if the effort in reverse engineering is worth it. It would be nice to do though :-) 

Since there are (max) 10 stations, the front panel power, sensor info and the ribbon cable has (only) 11 wires there must be some kind of logic/communication protocol active to be reverse engineered.
Once you know how the communication on the ribbon cable works you also need to create some kind of interface on the raspberry pi. Also this is doable but again is it worth the effort?

In your case I would not go for reuse of existing harware. You "only" want to reuse the driver logic and possible the powersupply for driving the valves. A 24v transformer and 2x 8-channel relay board are very cheap and you won't risk damaging you current setup.

--Gerard

[RKMason]

This should definitely be possible but I doubt if the effort in reverse engineering is worth it. It would be nice to do though :-) 

Since there are (max) 10 stations, the front panel power, sensor info and the ribbon cable has (only) 11 wires there must be some kind of logic/communication protocol active to be reverse engineered.
Once you know how the communication on the ribbon cable works you also need to create some kind of interface on the raspberry pi. Also this is doable but again is it worth the effort?

In your case I would not go for reuse of existing harware. You "only" want to reuse the driver logic and possible the powersupply for driving the valves. A 24v transformer and 2x 8-channel relay board are very cheap and you won't risk damaging you current setup.

--Gerard

Yes, I agree with you that it would be simpler to just build a 100% DIY controller, but where's the engineering fun in that?   I have a Digilent Discovery laptop scope and logic analyzer so it won't be too much work just to find out how Hunter controls their valve driver modules. When I have that info I can decide whether it's worth going forward or not.  At minimum I want to make use of my Hunter PRO-C case and 24VAC wall wort PSU.  Only question is whether I also reuse the valve driver modules and the power dist / control signal backplane mechanism already built into the PRO-C box. The possibility is too tempting to ignore.

[astrogerard]

Oh yeah, if you (like me :-) ) have all the equipment to have a peek on the protocol used between the front panel and the box then go for it. If you are lucky it is a well known protocol like i2c or spi or something like that.

Please keep us updated on your progress.