HiLetgo 3pcs HC-SR501 PIR Infrared Sensor Human Body Infrared Motion Module for Arduino Raspberry Pi

Function: My order included 3 units. Each of these worked. The device has controls for adjusting duration triggered and sensitivity (detection distance). Once triggered the duration ranged 1sec to 6min. These values are consistent w/ the datasheet. I did not test sensitivity. Electrical Characteristics: Sensor pin output (Vout) range 3.19-3.33v across the input range tested (4-7v, datasheet recommended VCC range: 5-20v). PCB is approx. 24mm by 32mm (15/16inch x 1 1/4inch). Solder joints are clean. Would buy again.

Nifty little motion sensor. Easy to code and use with Arduino or Pico 2W. Nice feature is the ability to adjust time delay and sensitivity.

Once you can figure out how these are supposed to work, they do the job well. There are differing opinions (documentation) on how long the delay time is supposed to run; I read anywhere from 30 mins to 3 mins (mine have measured about 2.5 to 3 mins). The sensitivity doesn't seem to change much. The trigger once / repeat trigger jumper is a nice feature, and makes it possible act as either a digital switch, or an on as long as an infra-red delta is detected. If the input voltage drops to about 4.7v, the sensor misbehaves, and makes it appear as if other parts are failing, because the data output line switches on and off erratically; however, what can you expect with incorrect input voltage.

These have been working without issue for my DIY ESPhome Home Assistant projects. I've ordered them 3 times now.

Used these to make some Halloween prop motion sensor triggers. These are alright and inexpensive for projects where you need motion detectors. The lens is barely held on and comes lose from the board, so had to secure with hot glue. The sensitivity adjustment does not work, as turned all the way down or up it will detect motion over 30 feet away still. Had to get creative with using objects to insecure it’s view from areas to not capture unwanted motion. The delay feature does work well though.

you need to use a transistor and power goes to motor and sensor, negative from motor goes to the collector pin on transistor, output from sensor goes to the middle (base) of transistor, u then have a negative wire going to emitter pin on transisotor and another negative wire for sensor ( that negative wire would go to where ever you have the negative spot on your bread board.

Inexpensive and versatile, this PIR sensor can be used to switch small, low power circuits or could be used to trigger a MOSFET for higher current applications as well. There are so many uses. I found the adjustments to be easy to make and stable once made. In my case, we used it to switch an LED strip for under bed lighting. When your feet hit the floor the LEDs come on as a night light to see where you are stepping without tripping over something. The sensitivity can be set so that the lights don't come on as you sleep. It's great!

At first I thought these were defective, but I found that when using it with a Raspberry Pi 4, it requires an extra diode before the V-in pins, otherwise some voltage instabilities from the Pi will cause false triggers very regularly on 60-second cycles (actually 59.75 seconds if you measure it out for a long enough time). After a lot of testing, including using it to drive an LED (no output to the pi itself), I was almost ready to give this a bad review, before I found some suggestions online for other HC-SR501 sensors regarding their behavior under power instabilities. I do not believe this issue was due to outside EM interference, as I tried it at multiple locations. Other than that, happy with the product and price.

Works as good as it says.

working good with arduino.

I ordered for my kid for experimenting with Arduino, he says they work great

the product didn't come with a jumper set and there were no pins for the H and L although they were in the photo!

No repeated trigger connection and no LDR SLOT.