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PIR motion sensor to trigger 3v relay module?

1763 Views 3 Replies 2 Participants Last post by  truwebs
Looking for help on my project. See image. Testing before connecting to high voltage device. This is my first attempt using a relay. Using a 3v relay triiggered by the PIR signal. As you see wired now, There is no ground wire coming from PIR only Red + and Yellow signal to relay.. The circuit would not trigger relay with a ground wire to the PIR. When this does trigger ( without the ground wire on PIR) I noticed on the relay that the LED would not go completely off. It dimmed showiing that the relay board was still receiving power. So I check to find that when relay turns/switches "off" the PIR is still sending 2.6-2.8 volts to the relay. Not enough to trigger the relay, but enough to show power through the LED. Obviously something wrong here where the PIR or Relay are still drawing power. Can you help?

Again note... their is no ground coming from PIR. This circuit triggers relay, but there is a constant 2.6 - 2.8 volts going to relay after the relay switches off from the allowed time from PIR. This keeps the light indicator on the relay dimmed. I am guessing there should be 0 voltage with no light. Hope you or somebody else can help.

Here are links to the PIR and 3v Relay


3v Relay

Thanks in advance for looking.

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Have you tried it with the grounds correctly wired ?
Yes, as stated earlier... When ground is connected to PIR, the sensor will not trigger the relay.
With ground connected to PIR and PIR disconnected from Relay... Voltage coming from output pin at PIR is 3.31 volts.
Now going back to no ground connected to the PIR when Relay does trigger, there is 3.26 volts from PIR output to relay. ODD.
Any idea the purpose of the jumpers on the relay board?
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