Adding a light sensor to a PIR module.
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- Опубликовано: 29 сен 2016
- It turns out that most of the cheap PIR modules sold for use with Arduinos have the facility to add an LDR (Light Dependent Resistor) so they only activate at night. This is quite a useful feature to have, so here's how to add one to a typical module of this style.
Note that the most common type of LDR is based on Cadmium Sulphide and as such the technically clueless eco-hippies are trying to get them banned under the RoFS (Reduction of Functional Substances) bandwagon. So buy 'em while you can.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm 
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I just realised I watch these videos not just for the accent, but the amazing dexterity in holding the board and solder with one hand.
I was a bio-medical electronics tech for nearly fourty years, and Big Clive is teaching me more of my trade than I ever knew before. Well done Clive.
I have to admit, this was *far* easier than I expected when I read the title of the video. I saw the title and thought it was going to be too complicated to be worth the effort, but as it turns out, it is quite simple. Thanks!
I have been contemplating a project that needs this exact function, so your video is perfectly timed.
Thanks!
I know nothing about electronics, but I still keep watching your videos..
you too will become addicted. I'm learning everyday And big Clive was the catalyst ☺
+retro80s I've learned so much from Clive's videos.
+Grandad Pop big Clive is a great guy I've purchased several of his pcb projects and they learn you enough and are fun and quirky when completed. keep up the hobby and enjoy .The thing I've found out about electronics is the hobby can easily last you a dozen life's and you'd still have plenty left to learn .
+therealnightwriter oh dear I'm illiterate. I struggle to spell words like suck my hairy ring piece.This ain't count down
Thank you Clive.
I had no idea that some of these PIR sensors would accept an LDR.
Thanks a lot for that very useful tip. Wasted a lot of time, unsuccessfully, trying to link an LDR and a PIR circuit externally until i came across your tip and it then worked perfectly
🙂Thank you so much for posting this! I'm just getting into messing around with electronics. I love the idea of letting my imagination run wild with fun ideas like this! I'm actually very handy with home construction and building motorcycles, so for me adding my own twist with electronics into those applications will be great. Thanks again, cheers from NYC ✌🏻😎🍻
Thanks for this Clive. I've just ordered mine to add the LDR for a porch entrance light
Sweet idea to make it turn off during daylight hours!!!! You have some really great projects and interesting and entertaining videos!!!!
To revert back to using the PIR module in daylight 6:18 just put some black electrical tape over the LDR.
You could leave the pins a little long on the back of the PCB and use a spare computer jumper block to enable/disable the LDR.
Fantastic Video Clive. Very Cool. Keep up the great work. Nick.
Thanks for the clarification!
I found in many datasheet that this motion sensor "gets better sensitivity in dark environment with adding an LDR"...,
but I can not found the appropirate resistance values for this LDR what I should add...
Now, thanks for you it became clear, that adding an LDR will not increase the motion sensation performace, it makes the whole module a "darkness & motion" -sensor what is absolute unwanted in my usecase (I have to sense motion in daytime and nighttime too.)
Thanks!
sweet !!! have been using external LDR with transistor , now all in one !!! great thanks.
Thank you very much for that info. i was always looking for that feature! really helpfull. superb.
Hi Clive, I'm a electronic noob. The project I have in mind is to build a 2x18650 PIR light that turns ON only during the night. Problem is there are external light pollution, so I gotta have a light-sensitivity adjustment function.
[1st qns]
You had talked abt adding a variable resistor in parallel to the 1M-ohm resistor to enable adjustment of the light sensitivity.
I needed this function to adjust the light-ON triggering point. Searched ebay but seems like 10M-ohm variable resistors are rare and expensive.
Are there any cheaper alternatives to add in this "light sensitivity adjustment" function?
[2nd qns]
for the LDR, is there any particular model to look for? I think not all LDR are the same rite?
Thanks in advance!
Ever since i saw the toilet led light I have wanted to make one that turns on using PIR but only when its dark. This would be just the ticket and will save hours of coding a micro controller. Thanks!!
I was being sarcastic. I already have the code from a previous project, this just means i dont need to use it or a microcontroller cutting costs
I have found using a 100k resistor in parallel with the 1m resistor turns the lights on around the same time as my solar lights come on
It is what I need. It is super simple. Thanks for video. Good work
Hi, I have a doubt. By placing the LDR, the two things work simultaneously? . I mean that if first the light sensor prevails and then the movement sensor. Can you make the light sensor prevail and if there is not enough lighting come into operation the movement?
Hi I am not an expert in electronics/electricals, I need help on my solar lamp post. During daytime, it automatically switches off. But comes night, it doesn't turn on automatically. It comes with a remote control that I can switch on manually. What could be the problem? Can I rig the remote control and add a photoresistor LDR and put something to press and hold the ON button? Where can I connect the LDR in the circuit of the remote control? What is the specs of the LDR? The remote is powered by just 3v 2x1.5AAA battery.
Great. I was looking this function for my project. thank you
You saved my life, thank you so much! ❤
Great tutorial Clive, Very interesting... :)
perfect. just the thing I was searching for! thanks :)
Amazing and so simple. And it works. Thanks. I found taht mosfets in 30s + mode give smaller output ad light is darker from 5v source
For low switching voltage you need to use logic level MOSFETs. They have a much lower gate voltage.
@@bigclivedotcom I'm using Irfz44z mosfet. It works pretty well, but wnen i'm turning knob of PIR to work more than 10 seconds - then it's light is much weaker. So it's pir's fault. Seem like it has different resistance. i'll try add different resistor.
Is there is a specific LDR needed for these PIR modules?
There are so many to choose from!
I have a circuit in which I have motion sensor with 5V and 220V bulb, can I use this all with that circuit?
If we use 9V battery in this to power RED Led, how long should the battery last ( in the situation where we want to use LDR)
If i add a light sensor to a PIR module to control a lamp , but i want to know when dark, and have a motion, the lamp is on, Is the light of the lamp affect the LDR and turn off it??? Thanks
can you provide a description of this added module with resistors and transistor?
hey.. rather cover the ldr with electric black tape... if you have a project that requier it to run at day light?
Technically clueless eco-hippies...couldn’t have said it better. Subscribed!
Thank you .Useful information.
I wonder if a 5 megohm potentiometer could be added to adjust the desired sensitivity?
I wish that things here in Brazil was this cheap. Sorry for the bad english. Nice project.
I wired mine so the LDR is separate from the PIR so that the PIR still notifies me when someones walking around my porch, but does not turn on the lights at day. At night it also functions a automatic light. But I noticed that the PIR causes interference with the LDR when the the PIR triggers. Will have to update the wiring it seems...
You could even cut the PCB trace leading up to that LDR and put a tiny switch inline, so you can turn on and off the darkness mode :P
This could be handy for a small battery powered door keyhole illuminator :D
Awesome video. Thanks. There is so many half thought out items coming out of china that could be so much more useful or actually work by adding a few components.
How is this a half thought out item? It works very well and is quite cheap. Plus it has provisions in the way of solder pads to expand the functionality. Too many people are too quick to bash things made in China as being inferior. We make some crappy stuff here in the US too.
Clive, could you make a video about inductors?
Sir what do you call to that connector in pir module? Thanks
Try adding a light sensor to a Fanny Flambeaux doll. LOL.
But it's manually triggered ;-;
Chucky blinking eyes ?.
I was thinking you could disable the LDR less permanently by sticking a bit of black tape over it... in fact since LDRs are so cheap they could solder one on in the factory and stick a bit of black tape over it for the end user to remove if required.
occurred to me that the likely fault in that plan would be the cost of having a person sticking tape on things outweighing the cost of components and pcb assembly.
Love the RoFS acro! :P
It seems to me all you would need is an LDR, a resistor and a small MOSFET to turn on and off the lights. Connect to light string anode to +12 through an appropriate resistor, to the drain of a TO92 enhancement mode MOSFET, a large resistor to GND from to the source and the source to GND, the gate of the FET to +12 V through a large resistor. when the LDR "sees" light it it is low R, and shunts the voltage on the gate to GND, shutting off the FET, and when ther is low light, the LDR is high R, and the gate turns on, with the LEDs turning on. A FET like this sells for 25 for $2
and cost, 2 resistors and a MOSFET would cost about $.25 or less.
Awesome, just what I was after! Thanks a lot, will try this out
@LostlnLeiden did you make it?
Thanks alot, very easy and very good hack!
Hi Clive, How can I use 2 PIR modules with one LDR, where either PIR will turn on the LED string?
I want to put an LED strip under the stair railing, with a PIR on each end. So the light will turn on when I am at either end of the stairs. Thanks!!
Just use one PIR per unit, and for the combined switching you could have one transistor per unit, but common them so either will bring on the light.
It's really an amazing feature
Mr Bigc, totally unrelated, but i have a question, since you seem to have a great knowledge of electronics.. i ordered a " Rotating LED Kit POV Soldering Training Kit" from banggood, and soldered it together, it works. its basically a strip of leds that are rotating and pulsing and making and image, based on the persistence of human vision. however, i noticed that the design have one resistor inline of each LED which is then connected to ground by the IC, why are they simply not sharing one resistor, but instead have one 560ohm resistor for each LED?
If more than one LED was on at a time the current through the resistor would be shared and the LEDs would be dim.
Thanks, that makes more sense in the morning. :)
Hey Clive what is that 3 pin connector called that you used? I was trying to find those for use in a computer fan project I was working on and I couldn't find the right phases to search on eBay.
It's a standard connector based on a Molex style. You have to buy the housing and contacts separately.
www.rapidonline.com/jyk-h2500-03-3-pole-crimp-housing-22-0910
Thank you!
Electro_Leet Specifically lookup the Molex KK series with 0.100"/2.54mm spacing. The contacts are available in 3 different finishes depending upon your application, zinc, phosphor bronze, and gold (with zinc being cheapest). They are wonderful general purpose connectors for projects for everything from signal lines to several amps as power connectors.
Do the light sensors trigger on IR light? I have plans to use the PIR module with a Raspberry Pi and an IR camera with built-in IR LED lights to detect motion, take a photo and then email the photo.
No. They detect longwave IR from body heat.
Hi clive. I have a riddle for you. I have ordered a wt588d-u sound module to connect a to my 2p machine and was wanting to use pir modules to instead of switches. The schematic or the wt588d-u shows the trigger pins put out 5v to the ground rail inorder to activate them. How would I connect a pir with that has +5v Sig and gnd pins in a 2pin application
You could use an NPN transistor to shunt the inputs to ground. You'd need a 10K resistor from the sensor to the base of the transistor.
@@bigclivedotcom thanks Clive your a legend.
What is best resistance for Ldr ?
Thank you, good to know it is ready for LDR. I am working on a DSLR camera trap and I wonder, how to reverse its operation - only trigger when there is enough light. Any thoughts? :)
Yes. The light sensing circuitry is formed from a bridge of the sensor and a resistor. Swapping their roles and adjusting the resistor value to get the desired threshold should work.
What is the specs of LDR ? I am trying to use a 5539, but it isn't working. It only disables motion sensing when the light is very clear, like when I am pointing a flashlight to it.
Try some common small LDRs from eBay. You can also nudge the intensity threshold by changing a resistor that forms a divider with the LDR.
@@bigclivedotcom I changed the LDR. The old one was varying from 1K to 2M. The new one varies from 4K to 53M.
It started detecting motions at about 5 PM local time, nature light. Thanks.
Hello sir, I’m very interested in doing this, but I’m actually a beginner. Is there anyway to help me with the cable wiring you are using, or anybody else, who made it. I need help with components you are using.
I have a couple of those modules. I just need to hunt down what I did with the bag of LDRs that I have. I need to organise all my stuff.
Neat little mod, could be useful in a home-made a bathroom light for those night time visits to the throne... :P
hi Clive :)
i see on the net that there are 2 pads for a thermal resistor, too, on that module... what is that used for??? Thanks
I'm not aware of a temperature sensing function.
thanks for the answer :)
look here: ozcott.com/NomadTronics/wp-content/uploads/2015/03/PIR-SensorModule.jpg
or here: i0.wp.com/dronebotworkshop.com/wp-content/uploads/2018/01/HC-SR501.jpg
Nice tip I did not know one could do it - Your video explained it well.
On a different note: Can you reduce the minimum "delay time" from the default 5 secs to even lower ?
Appreciate a reply.
If you look up the datasheet for the BISS0001 chip you will see that there are timing components that can be changed.
Hi Clive, wouldnt the LDR be a big current drain when using batteries?
Hi, I asked me the same question. But looking at 1M with 3.3V and Ohms Law: 3.3V/1.000.000 Ohms=3µA=38 Years with 1000mA LiPo. with 100k approx 3-4years. The sensor (50µA) would suck the battery within 2 years empty without and operation. with 100k (33µA) + sensor's 50µA we are at 1,4 Years. or am I doing wrong calculation?
Thanks for sharing...
Can you please share link of video you mentioned in which you put together 1 transister and 2 resisters with pir sensor to light the led strip ?
ruclips.net/video/evZM2_RTvTU/видео.html
bigclivedotcom thanks I might have npn transisters i will try
Nice video Clive!
Question: I'm assuming that u used a GL55 series LDR, can you figure out which one (e.g. GL5516, GL5528 etc.).
i have modded these PIR before with GL55
Friendroid Nice to hear, but can you tell me if it was a GL5516.....GL55xx?
i will reply to you later or tomorrow, as the datasheet is in my home computer. I remember checking the resistance of the LDR when dark, them confirming the serial number in the generic datasheet so i could buy another bag, however i cant remember the serial number now.
Not sure the exact type, but its dark resistance is off the range of a meter that can read 20M.
Just tried it with a GL5537. Worked fine.
My PIR sensor with the LDR doesn't sense motion anymore and only light the LED when it is dark. I want the PIR sensor to detect motion to light LED when there's daylight and just light the LED when its dark. Does soldering in the LDR disable the motion sensing?
+Andy Chiu Removing the LDR will make it look dark all the time.
Hello, Did someone tried with GL5537 ?
the same can be done to the smaller ones, but they may need a trace cut.
LDR 5549 working well !
Kool information to know!
Can you tweek the the dwell time? Many ready-mades are almost exactly what I want except they turn off after 30 sec, where I'd like 2 mins. Is there a simple way of modding them? Ta!
There are two pots on this type. One for delay and one for sensitivity.
bigclivedotcom thanks a lot!
hi good project it try to do the same soldering a LDR on my PIR Board. It is not working as expected. What kind of LDR do you use? do i have to do extra thing to do it working ? thx
Check it has the divider resistor fitted.
@@bigclivedotcom you mean that i have to solder LDR and another resistor to get a voltage divider ?
if i could i would send you a picture of my PIR Board setup ? do you have an email ?
is it possible to make these re-trigger?
Edit: apparently it's quite easy: there will be three pins (not the power and signal pins) with a jumper on two of them. Just move the jumper to the other pair.
There seem to be two versions, one with the link and one with the pads and a track acting as a link. If it's a link then try it in the other position to allow the unit to retrigger continually. If it's the pads then it should already be linked to retrigger I think.
Thank you
I have this working but mine comes on too early, when it's still quite light outside, can I add a potentiometer and where would I add it?
Is it possible to aim the sensor so it gets exposed to more light? Failing that you could bridge the resistor I mentioned in the video with a suitable resistor to make the unit less sensitive.
No, I can't get more light into it. Also, I need it to be more sensitive, not less don't I? Right now it's coming on too soon, I need for it to wait until it's darker before it comes on. Thanks!
nice find
You said you think the power rail is 3.3v and not 5v, but the schematic shows a 78L05 regulator. What regulator is actually used?
In the module the rail measured at 3.3V.
rjk the schematic isn't of the board he is using, it's just a generic layout for that chip.
Couldn't you just put a bit of tape over the photo resistor to turn it back to normal?
How do you solder anything with that novelty size iron?
Effortlessly.
Does the PIR sensor turn off when its day time, or is it still using the same amount of power?
It's quiescent current is very low. About 50uA in either day or night standby mode.
Is there any chance to get this working 24v dc power supply
Depending on the regulator it uses it may work at 24V.
Had a look at my PIR, same looking model, but mine has two set of pads, marked : "RT" and "RL"
Mine too, if anyone knows what the RT pads are for, please share with us unenlightened :)
RT is for a thermal resistor. You can trigger the sensor at a certain temperature. The RL pad is for the LDR, a nice tip put a potmeter over "R2" on Clive's shematic. This makes it easier to trigger
+Luc Put Thank you :-)
@@lucput6982 Would the thermal resistor be a PTC or NTC type for freezing or too hot temperatures? (Just now learning about this) Like if you wanted a heat lamp to come on only if temperature were below a certain temp? Any recommendation on this would be great.
But do i understand it correctly that the lights will only turn on when it's night and somebody is near (movement)?
Yes. It still needs to detect movement.
Is there a way to modify the PIR so an Arduino could adjust sensitivity/time ?
Sensitivity not easy unless you pulse counted. Time easy if it just triggers a delay in the arduino.
@@bigclivedotcom I have found out that pin 8 (RESET) can be controlled by an Arduino digital pin and now Im investigating if I can use a MOS 4066 and just a few resistors in the Op Amp feedback resistors. Inspired by Julian Iletts "Making a PIR Sensor Less Sensitive".
That's brilliant to know . I bought x 10 of the pir sensors for 3 quid.
Does it really works with ldr?? Wow
Halloween is coming. So an in darkness, motion sensing light string should be accompanied by some sort of medium-high pitched recording of the Wilhelm Scream...and perhaps actuated skeleton arms..
Will be try
Hi could you tell me how I can increase the output from 3.3v to 3.8v? Any help appreciated
Odd voltage, but there's a voltage regulator that could be changed. You could even change it to a 5V regulator if your supply voltage was higher than that.
@@bigclivedotcom Thanks for reply I want to use a 3.7v input to trigger a 3.7v 10mm LED as the 3.2v is too dim and it seems to be the max output for this module. Is there an easy way to do this?
@@markmaisy4858 The module won't put out enough current to light an LED directly. Is this video helpful?
ruclips.net/video/evZM2_RTvTU/видео.html
haha i have never seen the posibility to add a LDR on it. thanks!
can i change the block time of it?? accually it is written that it can be changed in its datasheet..but i do not know how to
The easiest timing component to change is the capacitor.
+bigclivedotcom thanks but i already know ... it is about which one to change
Block time, Ti = 24 * R * C. You need to check your PIR sensor's schematic to change the R and C value. If your sensor's IC chip is BISS0001, the R and C that affects the Ti is connected to pin 3 of IC chip.
Mine has LDR (RL) and also thermistor (RT) holes.
The RT pads appear to be in parallel with a 10K resistor that couples the first gain stage from the sensor to the second. I guess it just varies sensitivity so that it compensates for ambient temperature.
What value LDR did you use ?
The LDR was R_3 in the schematic.
5V/0. 2V = (R_2 + R_3) / R_3
R_3 = R_2/[(5V/0.2V) - 1] = 41.6kΩ
In daylight, we want to pull pin9 below 0.2V.
When light shines upon the LDR, its resistance diminishes. Less voltage drops across it and we fall below the 0.2V treashold. Thus, if you want to have your PIR trigger in more than complete darkness, you might want to choose a bigger value than calculated, so that more voltage drops across it even though there is still some light there.
That is what I think about the value of the resistor.
I'v never heard a one of those light sensors called a LDR before. That's odd.
They'v always been called a Cadmium Disulfide Photocells/Photoresistors when I'v seen them.
Light dependent resistors, apparently. But yeah, we call 'em photocells as well. Or simply "light sensors", as in the title.
I have spent most of today watching your videos. There epic, especially this one. Never knew you could tweak the cheap PIR sensor form china.
Thank you so much for this video. Would love to see a few more tweaking videos of cheap modules from china. :)
Are you ever going to use your nice snips? Every time you solder a component I wonder if this will be the time you use the nice snips.
I reserve them for the tasks where the very flush cut will be appreciated.
Surely that would be the nocturnal poop illuminator?
Could one make it only turn on in the presence of ghosts?
what do the 2 pots do?
Sensitivity and output timer.
Thanks Big C, you're a legend!!
Very kewl beans!
Stop hogging all the first/christian names!
Thank you for the video but we still did not have the PIR connected with a 12v led strip !!
You can get inline PIR sensors for 12V LED strips.
Thank you for the tip, so it mean that you can't use the Pir you show in the vidéo ? Because the inline PIR are very expensive compare to those small modules.