Forum Replies Created
-
Posts
-
10 ohm 25W resistor isn’t really adequate protection for shorts. In short situation the current will be 2.4A and power will be 58W (if the supply transformer can supply that much current). It can probably survive the overpower but will be REALLY hot. The supply transformer may be damaged from overload and the heat may damage things. Better to put in some sort of electronic current limit at a convenient level for a couple valves energized at the same time. If you have a system needing a very large number of zones at the same a more complex system would be needed but that’s an uncommon situation.
I have an OSPi (1.43+). I realize the OP has different hardware but I think most of this would apply. Had an issue with storm transients and some misconnection of an expander board that fried the on board regulator (if I recall correctly – it’s been a LONG time). I elected to remove the damaged regulator and feed the board with an independent 5V regulator so I could feed 12V through the unused ethernet conductors from a supply at the router using a UPS to avoid SD card corruption for short power drops. Not to get too long winded but that’s some back story. I added an in line fuse holder to the 24VAC input- ugly but it works and the fuse is easily replaced. I did build and bench test a solid state AC current limiter that is very simple – just a couple common transistors, some diodes and resistors. My plan was to install it in place of the fuse or possibly in addition to it. Since the fuse only powers the zones now I could easily put this in place of the fuse and only limit current to the zone circuits. Even thought of sensing the current limit and reporting it somehow. I didn’t have further issues so never put the circuit in place but should dig out the details and post it I suppose. My zone expanders have 2.2 ohm resistors in series with the triacs IIRC which just burn up in the case of a short. They burn the PCB making it hard to repair.
The fuse opened because I accidentally shorted things. Just replacing the fuse with a wire seems like a poor suggestion to me as the fuse prevented other damage. I can find other fuses that will fit. But I used an external fuse holder so the fuse is easily replaced and also a more readily available size.
I can get a picture tonight but it’s the one that came on the board when I bought it. I found a replacement that isn’t the same size that works. I just would like to know what the two parts used originally on the board for F1 are.
60′ with i2c or spi or any 3.3V logic signals is a horrible idea IMHO and not likely to work at all at least not reliably. From my quick checking “long” for i2c is something like 10′ and that is with buffering. Some sort of differential scheme would be a big improvement and probably possible. Something like RS485 for example. The other issue is electrical storm transients – again something like RS485 is much better.
Don’t know where you are seeing cost increases in the pi due to covid. The local microcenter still has a number of models up to the 3s for about $35 and many under $30. Seems the same as it always was.
I did something similar. I damaged the 5V supply IC on the OSPi due to an error connecting things. I also wanted a way to power the Pi during short power interruptions to prevent SD card corruption (had it happen several times). So I removed the power supply IC and fed the Pi 5V from a small 12V to 5V converter and fed 12V through the network cable from my wiring closed. 12V supply is powered by a UPS. Was able to find off the shelf parts – wall wart for 12V, power injectors for the ethenet cable, and 12V to 5V regulator. Works great.
Unless you set up accessing OS from the web you can only access it when on your local network, as you have found out. That’s how mine is still set up. There are security issues you need to be aware of if you put it on the web. I believe there are some documents on how to do this but it is a general network issue not something to do with opensprinkler.
I never got any reports that anyone got this working. That would be useful and nice to know. You say “it no longer works” – was it ever working for you? Surprised it doesn’t work because the API probably hasn’t changed. I don’t intend to update firmware (at least at this point) so it works fine for me and I have limited time to support this but I would welcome others additions/improvements/etc. Without more information it’s going to be hard for anyone to help you.
I finally put this on github. Not really familiar with how github works so I may have done some things in a non-preferred way but it is here:
https://github.com/jimls/ospiLCD
It works. Not claiming it is good coding… 🙂
I see it includes the original files which wasn’t my intent. My files are the new ones.
Hope this helps others…
It works very well. I have one sensor on the output of the filter and detect when it gets too low due to a plugged filter or problem with the pump pickup and shut down the system. I also have it send me an email 1 minute after startup of the pressure and notice if it shuts down. I have been meaning to post it somewhere but haven’t figured out github yet… I will try to do that.
Found it here:
https://github.com/OpenSprinkler/OpenSprinkler-HardwareSure would be nice to be able to get the schematic and BOM without having to install Eagle…
Not familiar with how github works – I have only gotten a few files there – but a pull request looks like a good way to go. I will look into that.
You could remove the 5V regulator chip or to avoid soldering just clip the leads at the package. Then power the PI directly and supply 24VAC to the OSPi board. I managed to kill the regulator and desoldered it. I set up the 5V supply to the PI from a UPS so I don’t have SD card corruption issues when the power goes off briefly. Works fine – actually an improvement in some ways.
I think this would be a great addition. For example, if you have a pump you may want to see what the pressure is. Guess I should put in a suggestion for addition…
It looks like you are trying to run an AC valve from DC. It will draw quite a bit of current at 24VDC. Ray has written some on the subject. It may be that the valve loads the power supply enough to reduce the voltage too much for the relay to operate. I suggest you measure the 24V supply with the valve on.
https://rayshobby.net/wordpress/understanding-24vac-sprinkler-valves/
I tried this on an older android. Didn’t allow me to add an existing picture either. Any update on this issue?
For anyone else interested here is a video that covers python, api, and json. This one and a couple of the following ones by the same person seem pretty good – not open sprinkler based but similar programming.
Ray,
I need to run the pump to build up pressure before each zone. See my later post here:
https://opensprinkler.com/forums/topic/station-delay-to-start-pump-before-zone/
Samsung J7, Model SM-J727U. Android version 7.0. Patch level June 1, 2018. When I click Add Picture it goes directly to the camera.
Master station on delay is only positive and off delay is only negative so that won’t work.
Looks like the only way to accomplish this is with parallel operation (uncheck sequential). If I have a spare/open zone before my regular zones, say zone 1, then regular zones 2-6,with 7 as master and 8 unused I can connect 7 and 8 together with a jumper so either one will turn on the pump. Then program 8 as a non-sequential zone. Say I want to run 20 minutes per zone. 6 zones is 1 hour, 40 minutes total. Set run time for zone 8 to 1 hour and 30 minutes. I am setting zone eight to slightly less than the end time to avoid the pump running past the end of the last zone. If I wasn’t worried about that I could just run the master as a non-sequential zone and maybe that would work fine but with delays between zones and such the exact end time is hard to determine and may not be accurate. Set zone 1 to 30 seconds (first zone usually takes a bit longer to build up pressure). Set the delay between zones to 15 seconds. The master station will shut off during the delays but zone 8 will keep the pump on during those times.Complex but that’s the only way I know of to do this. I welcome other suggestions.
I damaged the power supply IC on OSPi by miswiring so removed it. I inject 12V into the unused ethernet cable wires at my router from my UPS and drop it to 5V at the OSPi and put it into the standard Pi power connector. Power the 24VAC input of the OSPi in the normal way for valve outputs. During a power outage the Pi is powered but I can’t run the zones. I use a pump for water supply so I couldn’t water anyway. All the injectors and 12 to 5 V converter are standard stuff from Amazon.
