Inside an outdoor PIR sensor switch.

[@practicemakesbetter7132]

Great video, after watching your video I fixed two PIR security lights that had stopped working. I took them apart and tested them, it seems that the Achilles heal of these light sensors is the switch and variable resistors. After years of being exposed to the weather, especially if they are mounted so that the switch and resistors are facing upwards. The circuit board, switch and variable resistors become dirty from air pollution and the PIR sensor stops working. After cleaning the circuit boards, switches and resistors both PIRs worked. Thanks Clive, for teaching us how things work!

[@simonhopkins3867]

Wow look at how clean your bench was.

[@ElectroMech_polymath]

Great tips with circuit! My old sconce-style security lights definitely need a good inspection and clean.

[@christopherguy1217]

I really liked this one, I have gone through many of these PIR lights over the years for my driveway and I have found them to fail after 18 to 36 months. They always fail in the dead of winter (I live in Canada) during a cold snap (-20 c) after a warm few days where we have rain and melting snow. The failure mode seems to be the relay is frozen, the red led is on but the light stays off. You inspired me, I think I'll have to take one of the failed units to bits and see if a new relay will revive it.

[@JUANKERR2000]

The lens often gives a clue as to orientation, having fewer and bigger facets in the upper part and more, smaller facets in the lower section. All of the PIR units like that that I have seen have the adjusters on the lower surface which suports your comment about water proofing.

[@Mark1024MAK]

@Clive, the arrangement of using two Zener diodes as half of a full-wave bridge rectifier in mains PIR controllers appears to be very common. The same arrangement that you found here for the power supply/relay board is used in the four PIRs that I have opened (including one that is about 20 years old). The only difference is slightly different component values and not all of them have a snubber network for the relay contact.

[@danyk666]

The snubber is accross the load to prevent the LEDs from glowing when off.

[@H.T.2forever]

danyk666 Agreed, but how can the snubber circuit actually do its job of voltage transient protection for the relay if it's not placed in parallel with the relay as normal? Just replaced two 90w PAR38 halogen floods on an outdoor PIR motion security light with 90w equiv. 11w LED ones. And both glow at a very low intensity when off. Guess the snubber circuit is definitely in parallel across the relay here and leaking electricity through the flood lamps ...

[@howardsimpson489]

@@H.T.2forever The spike is generated by the load, so you can damp it either way, the faint led glow is probably the deciding factor. Led's will glow with amazingly small currents, just capacitive coupling in TPS cable is enough.

[@gauravsingh-gt5sh]

Thank you so much for the video.It Explained all the Basic stuff you need to know about the basic electronics

[@ostridge2774]

Screwfix or Toolstation version of the standalone switch by Zink Dion TS25151 uses a signal amplifier chip from TI. Ref LM324 with a 5v supply to the sensor board.

[@mozwell69]

Hello Clive, could you do a video on stubber networks, and what they do please. Thanks

[@MyBigThing2010]

you can install it with the adjusters up if you're installing on a porch or under an awning our any other application that doesn't get water

[@MS-yy2dh]

Good to see the inclusion of a relay (not all seem to have this), which I assume would allow an override switch, which would apply 230v to the output without damaging it.

[@bigclivedotcom]

The cheaper/smaller units that use a rectifier and thyristor should still be able to be bypassed with a switch.

[@MrBobWareham]

Mine point down, but it's failed now, so I will have a look inside to see if any water has got in, thanks for the video

[@xerman2686]

Would it be possible to connect a capacitor between PIR sensor and LED to achieve fade in and fade out...? I just love it when lights turn on smoothly.

[@MatSmithLondon]

What part number is written on your PIR chip itself? I've pulled a D203B from a mains switching PIR unit, which is driven by a BIS0001 IC (this doesn't do switching but rather control of the PIR chip I think). I'm trying to reverse engineer the PIR board to look at how they do fine adjustments for temperature as PIR needs this I believe. Any ideas what PIR and PIR control chip is used in the board you have here?

[@irishguy200007]

Excellent deduction

[@diyertime]

I just got one of these. Specs say Rated Load : 60W LED lamp , 300W Tungsten filament lamp, why would it be different? I suspect its a cheaper scr version as I hear no click. The red wire drives out "mains" or 120V line voltage as we say over here. I don't think that the wire sizes are large enough to handle 300W either. Mine is glued together :(

[@xbbjdf8]

Hi Clive, please could you tell me why some electrical components hum and buzz, what is normal and what might be a sign that something is wrong?

[@gardiner833]

I have a light with a pir sensor can I change for a normal switch?

[@steveclark..]

Which failed components are likely to cause, a) flickering of the light before it turns off & b) constant false triggering of the light? These seem to be the two most popular faults that develop with these sensor type lights, any pointers on what to look for please Clive?

[@pi5955]

My 2 new PIR sometimes triggered 3 times after switch on. So bad for AC lights.

[@honich-eriker]

​@@pi5955 The flashing at power-on is a sort of test mode and usually not as bad for lamps as you may think (except fluorescent tubes with bimetallic starters). If you want to avoid the test mode, don’t interrupt the sensor’s power.

[@rayfirth2513]

it is very easily converted to operate from 12 volts and is still reliable.

[@barriellewellyn7086]

Hi Clive, will the PIR relay handle 3 X10 watt LED lamps in Parallel. ie: the red wire from the Relay linked to 3 LED FLOOD lights relay output wire (Red). Will one relay handle 30 watts. I ask as I wish to connect 3 Flood Lights around my house to come on at the same time from any one of the PIR Flood lights that detect a movement. Regards, Barrie.

[@jahedurrahman6130]

Hi Barrie, I want to do the same thing as you. Did you get an answer or find out how to do it?

[@Mark1024MAK]

Jahedur Rahman If the relay is rated to switch that power, then yes. If the PIR module was originally designed for a filament lamp, then the relay will have contacts that have a suitable rating as these are often capable of switching 100W or more.

[@johanbotha9889]

That is not a transistor, it is a voltage regulator from 24V to 5V. The zener diode is used to protect the regulator in a crowbar method. So the voltage get reduced from 230V to 24V to 5V. That 5V is used to supply the PIR circuitry on the second PC board. The 4th wire is the wire to control the relay's coil. I had a problem with my security light due to alot of load shedding in our country. So every time they switch on the power from the substation an inrush current occurs, but the crowbar could not handle this on off swithing and inrush currents and it went short circuit causing to have a 0V on the 5V supply. I removed the shorted zener diode and the 5V came back!

[@adeliocelli281]

It is a transistor and it drives the relay as stated in the video. The zeners are very cleverly included in the bridge. As Clive says, the normal arrangement is to have a separate zener following a normal bridge circuit.

[@DevilizerHimself]

"Certainly mine has been pointing down the way for a long time"... Tried Viagra mate? :)

[@roundgarage]

Clive , I have the same motion sensor. How can I cut the time it is on to 3 seconds ?

[@bigclivedotcom]

You could probably change a capacitor to get a completely different timing range. If yours uses a BISS0001 PIR chip then you could find the capacitor location in the datasheet.

[@markflack9191]

Could you convert this to run on 12v if you changed the relay etc.

[@bigclivedotcom]

No need. You can buy 12V versions of the same unit online.

[@adeliocelli281]

Assuming you mean DC, you would connect directly across the output of the bridge which may be enough to drive the relay, otherwise you would have to change it out. Also the voltage may be too low to provide the current requirements of the 5 Volt supply. In that case the resistor to the 5 Volt Zener would have to be reduced to half its value (or an equal sized resistor could be added in parallel.

[@icsp2]

Mine has just failed yet again. I can here it clicking on but the bulb fails to light.

[@MyBigThing2010]

Andyman ummnm...replace the bulb...lol

[@deathtonwo9790]

frustrating All I want is a pir switched led lighting strip to go round a bathroom cabinet! I cant seem to find a video.

[@jayherde0]

What about wiring an outlet instead of the light fixture. then plug a power supply in to run your lights? Just make sure the power supply has proper isolation.

[@TheSlyMouse]

It's the light outside your house still functioning?

[@bigclivedotcom]

The current PIR sensor has been working for about 8 years, which is good.

[@RickRaulston]

Newbie question. How did it step down ac mains to 24 volts without some type of transformer?

[@bigclivedotcom]

It used a capacitor to ration through a small portion of electricity on each half of the sinewave. Very simple, but does not provide isolation from the mains supply.

[@fig8man]

where did you get that tester that you can clip the leads into?

[@bigclivedotcom]

It's improvised out of a short flex and three Wago lever connectors. I'd normally use a device called a quick test block www.ebay.co.uk/itm/171517360266 but don't have one here at the moment.

[@parthparmar9316]

Aa banavva mate in circuit no photo mokal jone please...

[@matakaw4287]

I have someone sneaking snacks out of the cupboard. Can I rig one of these up to catch them in the act? j/k These zeners are giving me mental complications..hahaha

[@dukesfly]

Thank you for the video, very mean to me

[@ridgep551]

Good info thanks

[@colinoverton8897]

I have an old incandescent 2 x 125w outside PIR light. Could I use the old PIR module off this on a new LED light module. The PIR module looks just like the one you have taken apart. Thanks, big fan.

[@MyBigThing2010]

Colin Overton no...the power relay will burn up LED units as the one you have is for use with higher wattage outdoor bulbs

[@scwfan08]

MyBigThing2010 The PIR simply switches the live. Why wouldn't it be possible if it then powers a, let's say, 30w power supply for the LED?

[@MyBigThing2010]

scwfan06 it switches the live and handles the current from the device that's now sucking power through it. ..pir...like all switches or components have ratings on what they are built for and what they are capable of handling. if you put a LED rated pir on an outdoor 2x 500w halogen.. you mine as well call the fire dept yourself ...right after you turn the circuit back on from the breaker box...cuz motion will turn on the light and there's a good possibility of components catching fire...best case is you just blow the PIR n it packs it in, "maybe" trip the breaker...but Murphys law is typically universal....there's always a chance that the unit will survive...but in an overdriven n HOT state...N heat and electricity and building materials don't play nice together...n the pir, in this case, is hanging in the breeze, very close to a wall and not protected in a junction box...so bbq time...just sayin...it's not a good idea to just stick components together if you don't know if the rating or internals will be able to handle the load (volts and/or current) you're putting on them ...safe than sorry ...if you're sure you have a bad ass pir and you're going under its specs then there shouldn't be a problem ....but just be sure what flavor of component you're using before making diy electrical spaghetti

[@Mark1024MAK]

MyBigThing2010 calm down! I think the OP wants to use a PIR that is rated to control 125W lights to control new low power LED lights. Not the other way round.... If the PIR module is like the one Clive took to bits (and all the mains voltage PIRs that I have taken apart so far, have been similar) then the answer may well be that it can be used to control a mains rated LED lamp. But if the PIR relay contact has a snubber network (so do, some don't) the LED lamp may glow slightly.

[@jayherde0]

Colin Overton - and other late readers .. If you are asking about the entire 'gray' unit, with mains in AND mains out, YES - but you may get some 'afterglow' when the light should be off. I suspect the difference between the data sheet and actual implementation in regards to the 'relay' has to do with relay-contact life and LED-afterglow. If you are asking about swapping individual boards INSIDE the 'gray' unit, that's much more complicated.

[@pi5955]

I bought 2 new pir using LP8072C lighting auto switch for switching fluorescent lamp. Both are from different seller and circuit a little different. After switch power on, the LP8072C sometimes will trigger on-off-on-off-on-off and stable there. Between on-off or off-on, it is about 0.4 seconds apart. I checked all voltages and even ref pin4 is stable and good. But why upon switch on, this LP8072C will sometimes output this false triggering 3 times? Do you have this problem? This is very bad for AC light because the life will plunge down fast.

[@alexa.davronov1537]

Reverse engineering, yeah, but where can we get schematics?

[@bigclivedotcom]

Plenty of schematics on my videos.

[@hansh2463]

I was looking for something like this to connect to a Rasberri Pi for outdoor. So if I get one, I could open it up and cut out the powerboard and use the detection board directly on the GPIO pins ?

[@bigclivedotcom]

That could theoretically work.

[@Mark1024MAK]

Hans H I have converted a mains PIR light controller for use on a 24V DC supply before. I removed the mains wiring and replaced it with a low voltage four core cable (sold as alarm cable). I then replaced the 560nF capacitor (or whatever value it was in mine) with a wire link. I connected positive to the "L" connection so that the relay now provides a switched +24V when it operates.

[@MatSmithLondon]

(Apols if your vid is years old and you don't have the stuff any more!)

[@AmitSharma-pu1lz]

Sir please English to hindi translation

[@GBlunted]

I just watched this whole thing lol😆

[@_Osman_Dag_]

The schematic drawing of the pir motion sensor with the Lm 324 is shown. Accordingly, let's cancel the time elements, namely the elements in the red area, R5, R6, R7 and C5. Let's connect the output of IC1A to the inputs of IC1B. Green lined area. Let's energize the circuit. Accordingly, will the relay be active as long as there is an obstacle in front of the PIR ? ibb.co/LpzpdWP

[@bigclivedotcom]

The PIR can only really trigger with continuous movement.