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June 6, 2014 at 5:33 am #22949
New to the Beagle Bone, OpenSprinkler and this forum, but 35+ years experiences with space base and terrestrial communication systems . With that out of the way, when my splash pad controller failed and the vendor wanted $1000 for a replacement, I looked for an alternate solution. I found OpenSprinkler and knew this could be adapted for this purpose. I was lucky to find the Beagle Board Black on the day a new shipment went up for sale. With my two new purchases, my initial test with the default sprinkler application has demonstrated this system should work for my purpose. I am now working on modifying the code to meet my splash pad use.
A couple of questions: 1) How many simultaneous solenoids can I activate? The previous splash pad controller had a mode when it would bring one on at a time until all 8 circuits were on then turn one off at a time. Assuming the 24VAC supply will handle all 8 solenoids, will the OpenSprinkler board handle the current load? (I find conflicting information on solenoid current draw, so I am going to have to measure it) Another mode had two random circuits on at a time. I would like to duplicate these features.
2) The images online show a set of blue screw terminals for the mini relay contacts. My board did not come with the relay screw terminals. What is the part number? I would like to bring out all three ports (nc, c, no).
I have no experience with python, but I have coded in BASIC, C, and PERL. I helped my wife with a Java class, but I didn’t learn too much (and she forgot it all). I have resources with Python experience at work, so I look forward to the challenge and posting the results of unique application of the OpenSprinkler OSBo. Thanks for any help and suggestions.June 6, 2014 at 1:33 pm #27099
Update – I believe the relay terminal I am looking for is Digi-Key ED2581-ND. The only limitation I see on enabling all solenoids at once could be the primate 2 amp fuse. Solenoid inrush information varies from 410mA to 800mA with holding current from 80 mA to 240mA. If I stagger the turn on by some time and the holding is really only 240, I will be OK, but not much margin for running the BeagleBone. I’m placing an order for the terminal block and case, and I would like to have a few spare fuses on hand. The parts list doesn’t list a part number. Anyone know fuse part number?June 9, 2014 at 6:11 am #27100
1) How many simultaneous solenoids can I activate?
As long as your input power supply has sufficient power rating, you can activate as many as you want. Each zone has a 800mA max current limit. There is, however, an on-board 2A fuse. In case you activated too many valves that triggered the fuse, you can always solder a wire to bypass the fuse.
2) The images online show a set of blue screw terminals for the mini relay contacts.
I don’t have the part number. These pins are designed to match standard 5mm or 5.08mm spacing terminal blocks. We do have some of these 3-pin terminal blocks in stock (sourced from China so I don’t have US part number). You can send an email to [email protected] to ask about it.
I have no experience with python, but I have coded in BASIC, C, and PERL.
The interval_program is written in Python, the sprinklers_pi program is written with wiringPi (which is similar to Arduino, a Java-based language). There is one very simple demo (selftest) written in C. You can use that as a starting point to see how to activate valves.June 9, 2014 at 6:15 am #27101
Oops, didn’t read your second post before replying. You’ve figured out the terminal block and fuse part.
and I would like to have a few spare fuses on hand. The parts list doesn’t list a part number. Anyone know fuse part number?
The one used on OSBo is a 2A 250VAC fast acting fuse (with solder pins). You can search on Digikey for similar ones with higher current rating — just make sure it comes with leads because there is no fuse holder on the board.
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