JeeNode Micro Driving A Relay
I am hoping to connect a PIR sensor to my JeeNode Micro, and have it send a data packet whenever someone walks up to my house door. The data packet is listened for by a recieving JeeNode (or Really Bare Bones Board device), and it causes a relay to flash a 120v incandescent light several times. This alerts me that someone is at the door.
I’m not having much success with a PIR sensor. I suspect part of the problem is it requires 5v power even though it is rated for 3.3v to 5v. The sensor seems to work with a 3.3v signal but not very well: I can’t get a steady sensor reading when I wave my hand above the fresnel lens. I probably have a lot to learn about these sensors and I need to give them 5v. Since the best the JeeNode Micro can output is 3v of power, I have not even tested the sensor on it yet.
As a start to doing practical work with the JeeNode Micro, I connected it to a push button. When the button is depressed, we get an active low state, and a sketch I adapted from the Arduino.cc site causes the JeeNode Micro to signal a relay which in turn flashes the 120v incandescent light mentioned above. I can get a JeeNode micro to operate the relay and therefore the light. Great.
The plastic cover on the relay and the relay’s heat sink is to prevent accidental touching of the load terminals. I simply found a Ziploc brand food storage container which is big enough, and popped it over the relay. The actual relay is mounted on a heat sink. Both relay and heat sink were purchased from phidgets.com and I’m very satisfied with the devices. I’m looking for huge safety margins rather than “just sufficient” capacity sizing.
Onwards to more complex stuff!
|jeenode_micro_connected_to_120v_relay_small_cropped.jpg (171 KB) jeenode_micro_connected_to_120v_relay_small_cropped.jpg||JeeNode Micro connected to a push button and operating a 120v AC Relay|
|120v_ssr_3_to_32v_dc_signal_input_small_cropped.jpg (145 KB) 120v_ssr_3_to_32v_dc_signal_input_small_cropped.jpg||120v AC solid state hockey puck relay and heat sink from Phidgets.com|
RE: JeeNode Micro Driving A Relay - Added by martynj over 5 years ago
> I suspect part of the problem is it requires 5v power even though it is rated for 3.3v to 5v
The PIR module has an on board regulator. For recent shipments, it is a 3.0V LDO. This drives the requirement for minimum input ~3.3V to give the LDO some operational headroom. Feeding 5V (or higher) will just make the LDO work harder.
With some surgery on the PIR module, this can work from a JeeNode Micro Boost 3.0V supply.