Using Sprinkler Controller to Control Wireless RF Transmitters to control small 6-12v DC Motors

Thread Starter

makrmaker

Joined May 17, 2021
2
Hello,
So I'm trying to wire this project together and I finally hit a stump.

Using a DC sprinkler controller to send signals to a wireless remote 433mhz transmitter to then trigger a relay to turn on or off a DC motor.

Having problems with PCB on the 15 signal 433mhz wireless remote transmitter. It's got a 15 - 4 pin switch's.
The switch's top left and bottom left prong have continuity with all 15 top left and bottom left prong as well has the pos and neg battery terminal to power the remote.
The switch's top right and bottom right prong have continuity with all 15 switches top right and bottom right prong.

So my idea to short the switch pictured below does not work, since when I trigger "zone 1" from the sprinkler controller. All the 15 zones will be triggered due to continuity.

Anyone got an idea how to trigger one signal at a time from the 15 signal 433mhz wireless remote transmitter?

If not, I can always run lots of wire from the motors directly to the sprinkler unit and forget about this wireless transmitter part. (Just wanted to save myself from a couple hundred feet of wire).

Thanks,
Makr

Setup:
IMG_0261.JPG

Wireless Remote PCB:
remote.jpg

4 way switch orientation:
swtich.PNG
 

LesJones

Joined Jan 8, 2017
3,172
The switches are probably connected as a 3 x 5 matrix. One axis will be driven with sequential pulses and the other axis will go to inputs. The simplest way would be to use an opto isolator for each of the 15 switches. When you say continuity how low a resistance reading defining as continuity. (I suspect you are using too high a resistance range on your meter.) Look at the signals on the switch pins with an oscilloscope.

Les.
 

Thread Starter

makrmaker

Joined May 17, 2021
2
The switches are probably connected as a 3 x 5 matrix. One axis will be driven with sequential pulses and the other axis will go to inputs. The simplest way would be to use an opto isolator for each of the 15 switches. When you say continuity how low a resistance reading defining as continuity. (I suspect you are using too high a resistance range on your meter.) Look at the signals on the switch pins with an oscilloscope.

Les.
That's what I assumed too, that the switches were connected in a matrix. Will look into opto-isolators, since I never worked with those before. Unfortunately, I don't have access to a oscilloscope at this site, as that would of been my next step. :(

Thank you for the response! This helps me out a lot!
 
If you can, figure what the highest value of resistor that works. That gives you an idea of the max contact resistance. You can use a FET optocoupler, PhotoMOS or OptoMOS relay. The latter two might only need 1 mA for the LED. I used a VTL5C1 in the past which is obsolete. You might even be able to use a CD4066 quad bilateral switch. https://www.ti.com/lit/ds/symlink/cd4066b-mil.pdf

The optical isolation method is foolproof.
 
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