Wireless switching w RPi

Hardware Server
1

Hi there,

I have one Rpi which is located close to the house for having a WLAN connection. I need to switch a couple of these Hunter magnetic valves and am currently investigating on a cheap solution. Main issue is that i don’t have WLAN availabitlity where the valves are located (garden). There’s only 230V AC available.

So far, I found 2 opportunities but looking for your input on any other ideas.

  1. Placing a 2nd RPi in the garden, connecting it via 433MHz transceiver & switching the valves with standart 8xrelais card.
  2. I found this wirless 4x switch actuator from Homematic.
    https://www.eq-3.com/products/homematic/switching-and-metering/homematic-wireless-switch-actuator-4-channel-din-rail-mount.html
    In order to use that switch actuator, I think I have to buy this addon card for the RPi since I don’t have any CCU from Homematic or using any other device currently.
    https://www.elv.de/homematic-funkmodul-fuer-raspberry-pi-bausatz.html

Does anyone have another idea for this use-case?

Thanks in advance,
Felix

2

Just flash some Sonoff basics.

3

Won’t work.

Main issue is that i don’t have WLAN availabitlity where the valves are located (garden).

There are other transcivers that might be a little more reliable than 433 MHz depending on how much interferance you will experience in your area. RMF69HW is releatively popular and easy to get working on an RPI or Arduinos. In this case I would use an arduino for the remote devices rather than a second RPi. It would be potentially cheaper, though a RPi zero is pretty cheap these days.

I don’t know these other technologies so can’t help much assessing those.

4

My relays are in my house and I run a very very long cable to my irrigation, not very technical but it works.

5

I also use your rain delay rule with weather binding that works great too.

6

I second that. And I’d write the Arduino code to include routines that dealt with the following scenarios:

  • Loss of RF signal (if valves are open, how long can they stay open if no new signal is received?)
  • Power cut
  • Power restart

I did this for my garage door opening /detection so if openHAB crashed or started misbehaving, the Arduino would act as a fail-safe and no weird garage door state would occur.

7

Thanks a lot for your help. I did my research and had ordered the stuff when I accidentially ran into an incredible cheap WiFi range extender from TP Link CPE 210.
That is covering my requirements and is even cheaper than above parts+time…