PIR sensor always HIGH

Hi,

I'm trying to connect a PIR sensor to my Arduino Uno board. The sensor was purchased from amazon and looks a lot like HC-SR501 (uses a BIS0001 chip).
I followed this tutorial Using a PIR w/Arduino | PIR Motion Sensor | Adafruit Learning System including the source code there.

The problem is I always have the input pin on HIGH. I tried adjusting the sensitivity but with no luck. I attached a picture of my setup.

The weird thing is, I think somehow the sensor works without the + and GND pins plugged in (just the output pin). Sometimes it behaves weird, but most of the times it detects my palm.

reydan:
Hi,

I'm trying to connect a PIR sensor to my Arduino Uno board. The sensor was purchased from amazon and looks a lot like HC-SR501 (uses a BIS0001 chip).
I followed this tutorial https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/using-a-pir including the source code there.

The problem is I always have the input pin on HIGH. I tried adjusting the sensitivity but with no luck. I attached a picture of my setup.

The weird thing is, I think somehow the sensor works without the + and GND pins plugged in (just the output pin). Sometimes it behaves weird, but most of the times it detects my palm.

PIR sensors are pinned two different ways (totally opposite). I can't tell by your pictures if you have it pinned correctly. Also, there's an added complexity because you added an interface. Instead, plug the sensor into a solderless breadboard and wire it up that way. This will remove a possible reason why it's not working.

I've spent countless hours working with PIR sensors. They're VERY simple and work very well. That's why I believe the problem has to do with how you're connecting it. Or, it's possible you have a dead sensor (maybe from wiring it wrong at some point). I have dozens of these sensors and have used them on all kinds of projects. I've never had a dead one or one that failed.

Tim

Thanks for the answer.

My sensor looked a lot like the one in the tutorial so I just wired it up like there. I don't use any interface.. it's plugged straight into arduino.
Also, this is the only way I've wired it. In my pics I have
Red = 5V
Black = GND
Blue = Ouput

For your experience, what other wiring should I test?

reydan:
Thanks for the answer.

My sensor looked a lot like the one in the tutorial so I just wired it up like there. I don't use any interface.. it's plugged straight into arduino.
Also, this is the only way I've wired it. In my pics I have
Red = 5V
Black = GND
Blue = Ouput

For your experience, what other wiring should I test?

You're using jumper wires soldered to a connector which is then plugged into the PIR sensor. That can be a potential problem and one cannot see how things are attached due to it. You could have a short in that connector. Instead, just use a solderless breadboard and jumper wires. Also, the order on the PIR sensors are opposite on 50% of them. Some are GROUND, SIGNAL, POWER, and others are POWER, SIGNAL, GROUND. I've never seen one that was POWER, GROUND, SIGNAL as you list.

Basically, throw away everything you have between the sensor and the Arduino. Plug the PIR sensor directly into a breadboard, and use jumper wires to wire up each pin. Then, detail the pin ORDER and the SIDE you're looking at on the sensor. I fear you have it wired wrong or there's a short as it is now. Which is why things are not working correctly for you.

Tim

I only used a connector because I didn't have a female-male wire. I measured and there isn't any shorts between the pins.
I'll measure again tonight just to be sure.

The wiring order I used is GROUND, SIGNAL, POWER (black, blue, red) when you look at the back of the sensor and the pins are on the bottom.

Thanks,
Andrei

reydan:
I only used a connector because I didn't have a female-male wire. I measured and there isn't any shorts between the pins.
I'll measure again tonight just to be sure.

The wiring order I used is GROUND, SIGNAL, POWER (black, blue, red) when you look at the back of the sensor and the pins are on the bottom.

Thanks,
Andrei

Do you have a solderless breadboard? That would be a better way to start to make sure you don't have somthing buggered up.

Tim

Yesssss... it works :slight_smile:

I used a breadboard and salvaged a nicer 3 pin female connector from an old cpu cooler but it didn't change anything.
Then I switched the power and ground pins and now I get a nice 3.3V when movement is detected and 0 when there's not.

Thanks for the help

Hi, i have similar problem.
This is my PIR module: http://www.ebay.co.uk/itm/1X-HC-SR501-Infrared-PIR-Motion-Sensor-Module-for-Arduino-Raspberry-pi-/131563223769?hash=item1ea1c77ad9
Here is an image from bottom:


I always have HIGH from OUT pin. Sends high while GND cable removed from pin.
I just switched VCC and GND, still got high.

It is very similar like this panel i found on Adafruit.com. Main difference is the jumper for change sensitivity from 15 to 30 feet.


On my panel, i have 3 connectors and H is connected to middle on pcb.

I have more than one from this product, each one is works like this.

These sensors are very easy to use.

Turn sensitivity all the way counterclockwise, otherwise you have to sit VERY still for SEVEN minutes before it turns off.
Leave the sensitivity pot in the middle.

You can also test these sensors by connecting a LED between out and ground (anode to out).

DON'T swap VCC and ground. You might destroy the module.
Leo..

Hello,I am doing a project on motion sensing light with pir without using arduino. But my pir is not working.It gives high out put when the ground pin is disconnected.Also, if the vcc pin is disconnected,the pir gives high out put for sometime and then stops working. What should I do?

deepita:
It gives high out put when the ground pin is disconnected.

Why would you do that.

deepita:
Also, if the vcc pin is disconnected,the pir gives high out put for sometime and then stops working.

Why would you do that.

deepita:
What should I do?

Connect VCC and ground to a 5volt (or 5-12volt) source.
And a LED between output and ground (cathode to ground).
It could take upto 10 minutes for the LED to turn off after the last movement was detected.
Adjust with the "time" pot.

If that works, you can replace the LED for a transistor that can switch a relay or a light.
Leo..

Wawa:
Connect VCC and ground to a 5volt (or 5-12volt) source.
And a LED between output and ground (cathode to ground).
It could take upto 10 minutes for the LED to turn off after the last movement was detected.
Adjust with the "time" pot.

I have tried doing that but it doesn't work. The LEDs glow only under the conditions i mentioned earlier.

How about the case that the output becomes high when you touch the wire? It looks so magic

To turn both switch counterclockwise and wait for a while worked for me.The PIR back to work again.

I just started playing with Arduino, and having the same problem. I had OUT high always.
After trying and trying, I found that some of the tutorials labeling the VCC and GND just opposite from the product, or the product label is just opposite from tutorials. I switched the VCC and GND, it worked just fine. A week of trying. Worth it.

My PIR was purchased from Amazon. The product itself has no VCC, OUT, and GND print. That's why I wired it based on some tutorials. The correct one was from images.google.com.

Make a good search from Internet before any project. That is what I learned.

Hopefully it might be of somewhat help.

Colin

I have a similar problem with mine. I hooked up a PIR to Pduino patch (Pure data for Arduino) and my sensor is only emitting 3V at regular intervals of 4310 ms. It doesn't seem to react to movement whatsoever.

If I change the sensitivity and delay time it doesn't seem to do anything anymore (even if I wait for a couple of seconds ore minute). I bought a few and I have the same problem with all of them. Any I ideas what I could be doing wrong??

Thank you for taking the time to post this. You just saved me a week of troubleshooting this.

I owe you a beer.