@@mikebarrett2621 A truly egotistic observation to steer attention to ones self, did my comment showing praise & appreciation for another person trigger waves inside your shallow mind.
@@mattelder1971 oh yeah! to be sure.. though usually, those things are mounted up high away from other (usual) sources of light.. AND, I have seen lightening STILL trigger them just the same.. thanks for the reply! :)
It is there to act as hesterisis. When the light level is just equal to the threshold value then it migh switch between the two states rapidly which we don't want
@@MrDaniyalAh The capacitor and resistor won't provide any hysteresis. The relay will do that. The voltage threshold to turn a relay on is always higher, than that when it turns off.
I had the Philips Electronics kit for Christmas when I was a kid, with an 'Automatic Night Light' circuit (my fav circuit - it even came with a green cover for the 6V bulb!) ..imagine how old I feel, that was around 1971 🤣
@@cornwallonline I had the same sort of EE kit, but I remember that there was no relay involved. A relay needs to switch fast enough to avoid burning in of the contacts, and that is a weak floor in the above design.
Quite right, TheEPROM9. The nice thing about CdS LDRs is that they're not only as tuff as old boots but they're bidirectional too and can be used on AC. In fact, when I was a boy (I couldn't resist saying that!) all this type of unit contained was an LDR and an hot-wire relay. There were no semiconductors at all. The hot-wire relay provided a bit of hysteresis.
I know very little about electronics Clive, but your calming voice and method of description in all aspects of your videos, especially your reverse engineering, is superb (even for a novice like me to grasp, to understand and get the gist of what's going on). *Your videos are a great stress reliever, believe me, thank you! 🙂👍
2:03 I would cut a short piece of extension cord, remove the inner conductors so I only had a jacket. Then I would squirt a bunch of caulk into that sleeve and run the conductors through it, thus making it both waterproof and jacketed. Then run that short cord through a gland and into a junction box.
I too would have put my money on there being a 555 driving the relay. This configuration is nearly more simple than a 555 circuit. Very interesting piece of hardware. Thanks for taking it apart.
Bought the same item in Greece for 2.60€. I mounted this on a piece of PVC pipe that I sealed with a cap on the bottom. The top of the pipe needed a few turns of cheap electrical tape to get a tight fit. Its been working now for five years with no issues.
Reminds me a bit of the mini photocells that are usually mounted within street light fittings with single core wires coming off it and the actual sensor itself is screwed into a hole on the light fitting
The simplest light sensors are the thermal types, with a big LDR and a resistor in series across the mains. The resistor is thermally coupled to a temperature compensated microswitch mechanism. Simple, reliable, and for some reason replaced with relatively complex electronic solutions nowadays.
A 24 V DC relay pulls in (like they all do) at 80% which equals 18 V. The drop out is less standardized, but has to be before the voltage disappears completely. My findings have been anywhere from 2 V to 8 V. Anyway, with exponential charge and discharge, you can usually see different time delays in the two directions. This in addition to what the other component values and ratios cause.
BS7671 requires a sheath over the insulation. The cable doesn't need another layer of insulation. The sheath could be another layer of PVC, but we could also choose to use copper (MICC), Lead (PILC) or steel (conduit).
I have a Turkey-sourced one with a virtually identical instruction leaflet, but with a more rectangular 'dome'. I built it into a waterproof junction box, with a suitably sealed orifice, along with a 12v transformer and the combined unit now powers my 12v patio lights. BTW, have you noticed that, before the EU, electricians had to be 'experienced', now they only have to be 'qualified'.
@@dfpguitar Very fair point for the condensation and temperature, but regular glass and many transparent plastics do block most UV light, which is why you need crystal tubes for UV sources.
You can't have un-sheathed wiring whether it's indoors or outdoors. The flex on your TV or kettle cannot show exposed brown and blue cables, and neither can cables for fixed wiring such as this. The sheath must be continuous from the appliance to the plug or wiring enclosure.
@@TDOBrandano not disputing that glass blocks some UV, but it is clearly not all , because if it was. All the plants in every glasshouse and polytunnel in the world would die. Also, there would be no need for UV coatings on spectacles or even welding masks.
It would be interesting to see the CE mark approval paperwork. Since it will have to be recertified to CUK and or CNI next year as we leave Europe the approval paperwork may be more accessible.
Hi BigClive. A quick search of 'tutorial' on your back catalogue revealed nowt, but just so that you know, (you almost certainly already do), you have an amazing voice to listen to. Perfect for online tutorials. Now there's an idea! Have you ever though about doing online tutorials for beginners? I suppose it might be a bit tedious for you, but I for one would enrol on one of your courses I'm sure. I'm an electro-mechanical engineer, but somehow I always felt like I missed out on the whole semi-conductor age. Would love , love LOVE to know more than I do especially if you're doing the tutoring. Regards Mark in the UK
That switch design with LDR is mainly the first design you could find after the transistor came to market at the end of the '50. And it would have been shot down immediately for the gradual raising of the voltage on that relays, and for that sparking contacts. We miss a thyristor as a clamping mechanism; using that under its clamp current you wouldn't even need to reset the thyristor.
You have me thinking now, Clive. I have a "Zodion" style, and I emphasize the word 'style' which I bought on-line, and which failed about six months later. It came in box labelled up as "Newlec". I naively took it at face value, and installed it, and was duly disappointed when it failed. On attempting to remove it from the Zodion socket, the opaque dome fell off in my hand! Once down from the ladder, it was clear that this thing was a fake, and a poor fake at that! Under the lid, there was the capacitive dropper, a very sick looking resistor, what appeared to be an LDR, one small electrolytic capacitor and a three legged silicon device. I saw precious little else, though there must have been a rectifier of some sort, somewhere, and I'd guess there was a relay. Granted, this was about seven years or more ago. I may still have it somewhere! When you described yours as the simplest you've ever seen, I swear, you could have counted the components in this fake, on the fingers of one hand! if I were to find it, would you like to cast an eye over it?
You can sleeve the bundle of wires between a JBox with appropriatle rated flexible conduit. The units would be positioned well out of the reach of anyone accessing it, requiring a ladder and you would isolate the cct before attempting to access the light fitting or JBox. Zeena warrior princess diode.
I used one of these a few years ago for lights in my chicken coop, it was a 12 volt version though but had the same design. The way I dealt with the single insulated cores was to put heat shrink around all three together. Eventually it stopped working, so I replaced it with a new one which still didn't work, and yet the lights worked if I bypassed it. Very odd since the first sensor worked perfectly for a couple of years. In the end I just got rid of it altogether and used a timer to control the lights instead.
If these stop working after a year or so, first check to see if it's covered with bird manure. I recommend any outdoors installation have a clear cover over it that can be thrown away when needed, like half a clear plastic soda bottle.
Nice one Clive, it's a simple and classic design. At 1600 ohms as per the datasheet for the relay, that transistor is going to have an easy life, 22VX22V/1600 ohms = 0.3025 Watts. Magnetic hysteresis with some help from that diode to ensure the gate current goes away completely during the day. it's clever, thanks for tip on how to design an enclosure for my temp, humidity and barometric pressure sensor, the traditional designs are a lot of work and the tolerance to driving rain is an issue unless a lot of attention is given to the louvers. So I am going to make it look like that, with holes in the base for air to in and out past the sensor. Take care, regards from South Africa.
@@eDoc2020 Yes SOT23 packages are like 200mW At partial conduction with 11V across the transistor it will dissipate 75 mW. The current through the relay will produce the highest losses when fully energized, during the night. During the day no current flows through the transistor and then there's a brief period of partial conduction at dusk and dawn. The zener diode is going to steam a bit during the day with no load on the dc side. That might get to between 300 and 400 mW. With the copper around it being minimal I would expect that area to turn brown over time. They work, it's a cheap item after all, so it's the level of engineering one gets for the price.
Possible reason for the loose wires is that, in would need to use 4 core flex. It is rare to get 3 core in anything other than positive (brown), negative (blue), earth(green&yellow). It would be very stupid to use the earth wire as the output. So that means going to 4 core with an white or grey additional wire. That would be an additional cost and a redundant earth wire
I think this cout be used to great effect for patio lightin and such applications that ta dry to "damp" but covered. Could make a simular unit but replace the ldr with a RTD and use it for the infra red patio heater. Would probably need a 24hr timer for that in the colder months though.
I'm guessing that our host did not read the instruction leaflet - it explains that the black bag is for testing the sensor without having to pray for a convenient eclipse.
I think this type of dusk sensor is used indoor, like factories, offices etc.....where there is a skylight used, if the light from the skylight is below the treshold, the electric lights come on. I worked at a place, that used this system to save on electric costs of light, but it was very annoying on cloudy days where the lights are switched on and off multiple times within few minutes.
Thank you. Another interesting video. Just made one of these ldr circuits for the lights for the tree outside our village pub. I was thinking of adding a capacitor to 'damp out' sudden light flashes from passing cars and wasn't sure how to. Would that work? I love your videos, they are so informative for an old beginner with a very limited knowledge of electronics. I've learned so much. Thank you.
@@bigclivedotcom Agreed, for a reputable UK supplier this is inexcusable; pretty sure these will be on there soon. May I wish you a Merry Christmas and and blooming better 2021.
Heatshrink over the leads would make it somewhat double insulated.... And it would helf against UV light. (insualtion gets brittle over time)... Thats a very simple circuit, which in some form or the other, i have used a lot in the past.
The cable doesn't need another layer of insulation. BS7671 only requires one layer of insulation, but it must be covered by a sheath. Double insulation relates to appliances. It sounds like a tedious point of terminology, but a cable's second layer doesn't have to have insulating properties. It is there for mechanical protection.
Need to start giving names to the Impact/Skid Marks on Clive's Desk. Problem is the 1920*1080 XY Origin may keep changing depending on exact Phone position. Might have to resort to using the somewhat stable BigCliveDotCom as a reference 😁
Could be the different ratings in the condensers due to the timing delay needing to be more or less consistent between different devices, so greater "precision" condensers were sourced to that effect? Given that electrolitics have a wide tolerance in capacity generally
Looks like it should be mounted on some sort of pole so the cables go down inside the pole or directly on top above an outside conduit with its bracket slid behind the conduit and attached to the wall. It looks to me to be some sort of conduit sensor with those wires
It's unfortunate they didn't just put some uvb or another type of outdoor sheathed wire on there. Also a gasket between the case and cover to make it usable outdoors. Alternatively even a larger bezzle so it could mount on a standard light fixture box. So many possibilities, so few acted upon.
With such a simple circuit design, that has no hysteresis or schmitt trigger arrangement, I wonder what it’s performance is like when the light level is very near the switching point. Especially if even a bit of light from the controlled lighting finds its way to the sensor...
Oh my word!! I really need to get myself to Specsavers for an updated prescription because I read the intro as a DUST detector and didn't cotton on until you switched off the light. I kept wondering where are the vent holes to let in dust laden air and why on earth would you enclose it in a plastic housing???
Did you notice that the HOPI doesn't flicker when the lights are off? I guess the flickering has to do with the type of light used in the room plus the camera. That is cool though that without the lights on there is no flickering.
It rather poor that it does not use a Schmitt trigger to drive the relay. Is there magnet or mechanical hysteresis in the relay contacts. Without this feature, what stops an arc developing across the contacts as they open? I suspect that hiding the LDR between the other component might have been intentional, as it would limit the source of light to that coming from above, reducing the chance of triggering from say car headlights
@@bigclivedotcom I assume this is the result of the gain in the system, however testing with an on/off light source, like a torch, might produce different results to that of a slow sun rise.
Every time I look at the EU power line colours... I think how easy to remember it would have been if brown was for earth brown return a earth potential, and blue was for blue sky hot ... where the lightning comes from. I'm OK with the earth green/yellow.
I wonder if this is a similar circuit to the detachable parking lights you could get for cars in the 1960s? It was used to turn a red “parking light” on after dusk.
Something seems a bit odd with the schematic. When the LDR is illuminated, the adjacent diode will block it from discharging the timing capacitor. So the capacitor can only discharge via the 47k into the base of the transistor. Which is fine I suppose to make the delay, however the slightest leakage current in the transistor will tend to make it turn on since there is nothing to actively bias it off.
Transistors have a parameter called Iceo which is the collector to emitter leakage current with the base open circuit. Provided this is less than the operating current of the relay then there's no problem. Or am I being naive to assume that Chinese circuit designers read data sheets.
With a bipolar transistor, there has to be enough current flowing through the base multiplied by the gain to allow enough current to flow via the collector to energise the relay. The capacitor will soak up any stray electromagnetic fields, and at 22V, I would not expect any significant leakage from the collector to the base. So it’s fine.
It would be simple to add a length of 14/3 * waterproof line from the guts of the gizmo as long as you needed. That would make the box pass Clive's stringent requirements. I think the gadget would be suitable for North America's 120 V standard as it sits, of course, my understanding of code is a half century old by now. The circuit might supply 22 V even from 120 V.
"Clive's stringent requirements" ?? They're not stringent at all, in fact they're very practical. I believe the code for outside is that it must be housed behind plastic or metal and be waterproof. The only exception I know to this is the double insulated romex made for direct underground installation. Squirrels & rodents will pretty much tear off insulation when given a chance which is only one of a myriad of reasons it's smart to have physical protection for outdoor wires, especially permanently installed ones.
The U.K. requirement is that any mains voltage item/equipment/appliance etc. must have any exposed PVC or rubber cable (meaning any cable outside of the case of an item/equipment/appliance etc.) made of insulated conductor with an outer sheath of a different colour. The line (live/hot) conductor should have a brown colour insulation, the neutral conductor should have a blue colour insulation. Alternatively cables can be run in suitable conduit. If used where there may be exposed to water, then suitable waterproof/weather proofing arrangements should be done, such as rubber seals.
@@Mark1024MAK mmmm. I meant US codes. It's not even allowed indoors anymore, either, because I was told by an electrician my laundry receptable is not up to current code even though it doesn't have a scratch on the cable and no signs of wear. But it does come out of the hard metal conduit and hang down about a foot and half. I don't agree with that but obviously I can appreciate the thinking behind it.
Pro-Elec branded items all tend to be Chinese stuff with their brand stuck on it and then just stick in a bit of their own paperwork. I think its pretty much a CPC exclusive or in-house brand.
EDIT: Nevermind, it was in your "Random stuff on my bench." video, at least I'm not crazy... Oh, who am I kidding? I'm getting deja vu, didn't you already make a video on this exact same unit, where you also mentioned that it'd have to be in an enclosure if used by business owners in case a customer/employee grabs the wires? I'm probably dreaming of Bears with dusk switches again.
Ut has occurred to me that you drill a suitable hole in the top of the luminaire to the diameter of the base of the cone. Run some sealant around the lip and job done
That sounds like getting a good long term seal would be difficult. My employer has lots of equipment that is located outside. It’s quite amazing (and very annoying) how rain water can find it’s way in through the smallest of cracks. Even through threaded blanking cable hole ‘bungs’ (blanking caps) [some of the equipment is modular so you can stack them, with aluminium cases with all the holes already made, whether you want them or not]. Even trying to seal them with silicone sealant does always not provide a long term solution 😕
@@Mark1024MAK agreed, and you never want an airtight seal otherwise you will get condensation. As long as it keeps the connections reasonably dry your on a winner.
In South Africa you can have single insulation as long as it's run inside pvc conduit I'm not sure about the British regulations. But perhaps the aforementioned is an option ?
You say the inrush resistor is 100R, but itn't it 10R? There is another white band after the gold, so the gold is considered a 0.1 multiplyer. 101x0.1 = 10.1R. Never seen a _white_ tolerance band before though. Maybe I'm mistaken somewhere. Would appreciate any feedback.
I suspect that the gold is the tolerance and that the white band means something else. Primarily because 10Ω or 100Ω resistors are going to be far more available (and hence cheaper) than 10.1Ω resistors... Also a 10.1Ω resistor would be a close tolerance part (better than 2%) , and would cost more than a 5% tolerance part. Can’t say that I’ve seen a white band like that in that position before though.
Given how it's designed it would be very easy to replace those wires with a piece of cable. All you need is a Philips screwdriver and a soldering iron.
Simple design, reminds me of my first learning with one of those Science Fair kits. I agree on the 1M resistor. I personally like through hole. They should of used multicore flex, but then again this is not something I'd buy to actually use. As with most ebay chinese specials, its good for spares and modifying ;)
Their customer service needs improvement. They told me that they are exempt from the Consumer Contracts Regulations because they are a Distributor and not a Retailer.
@@westinthewest Their website would suggest otherwise, so I would badger them about it if I were you. I've been buying stuff from them for over a decade as a random civilian rather than a business
@@Wanton110 I did tell the nice lady that the Consumer Contracts Regulations state that an attempt to mis-inform a consumer is a criminal offence, but she continued by saying that an LED product (e.g. integrated downlight or floodlight) was classed as a consumable item similar to batteries incandescent bulbs. This was another reason why a return could not be authorised. I had a half-hour conversation that wasn't very inspiring. Edit: I opened my account with them in 1989 when they were the local electronics shop in Leeds. I still order stuff from them, but with caution.
@@ferrumignis That's a good question. Maybe temperature? After dusk it's likely to be cold outside, but if the sensor sits in direct sunlight throughout its days with the coil partly energized (brit:energised) it could be more prone to it. I've had it happen before, which is why it came to mind, but yeah, it's not likely. I probably over-drove my relay, heating the core with a warm coil. I was very young at the time.
Circuit looks like what I used to see in some old electronics project books for dusk sensors. Yet again the Chinese seem to be giving these circuits a new lease on life.
We just inherited some of my grandfather's things. So many cut-off ground pins (US plugs) and all the halogen lamps were missing their safety glass. Then again I've built a light bulb box. Three bulbs hot glued in place and all the wiring is exposed, you could easily get shocked using it.
Probably not a whole lot more "legal" but I wonder if one might be able to run those wires through some kind of an insulated or sealed tube to afford them better protection...
“Watch your eyes, the light is coming back” 😌 Considers others at all times, quality person & content.
Does not vote Conservative (Republican in US)?
@@mikebarrett2621 A truly egotistic observation to steer attention to ones self, did my comment showing praise & appreciation for another person trigger waves inside your shallow mind.
And he zooms in for those of us watching on mobile so we stand a chance of being able to see it too
@@Dust76tr 💯
Instructions unclear. Eyballs twisted into torroids.
LDR, transistor, and cap for time delay... this is right out of a classic era kids' electronics kit
Precisely!
It did make me think of a beginner magazine project.
Maybe I'll stick a thermistor in and turn it into a matching thermostat.
@@bigclivedotcom Or just stick a few resistors across the output and turn it into a dusk activated party popper :p
Hence the price
The 8 second delay is probably to keep things like headlights from passing traffic from accidentally triggering it.
You almost guessed it.. its actually cause of LIGHTENING FLASHES -don't want lightening to cause the lights to flicker on and off esp HID fixtures! :)
@@WarpRadio Well, I did say "things like". I'm sure there are several possible sources of random lights, and that delay would counteract most of them.
@@mattelder1971 oh yeah! to be sure.. though usually, those things are mounted up high away from other (usual) sources of light.. AND, I have seen lightening STILL trigger them just the same.. thanks for the reply! :)
It is there to act as hesterisis. When the light level is just equal to the threshold value then it migh switch between the two states rapidly which we don't want
@@MrDaniyalAh The capacitor and resistor won't provide any hysteresis. The relay will do that. The voltage threshold to turn a relay on is always higher, than that when it turns off.
Start days tomorrow, I get to watch Clive before bed, good way to unwind relax. Cheers.
I particularly like how it's marked as being double insulated.
It's pretty hilarious what those marks are found on sometimes.
But it is, both the wires are insulated
Double insulated means it doesn't need to be earthed
the thumbnail looks like a Styrofoam cup with some wires glued on it lol
I thought this too. Thought it was going to be an electronic cup on a string telephone contraption.
I had the Radio Shack 200 project electronics kit and I remember the light sensor experiments.
Great, now I feel old...
I had the Philips Electronics kit for Christmas when I was a kid, with an 'Automatic Night Light' circuit (my fav circuit - it even came with a green cover for the 6V bulb!) ..imagine how old I feel, that was around 1971 🤣
@@cornwallonline I had the same sort of EE kit, but I remember that there was no relay involved. A relay needs to switch fast enough to avoid burning in of the contacts, and that is a weak floor in the above design.
@@cornwallonline my favourite was the superregenerative receiver, that made a fine air band receiver 😁
Use to find LDR's in everything back in the day. Photo diodes & transistors were just of fancy electronics.
Quite right, TheEPROM9. The nice thing about CdS LDRs is that they're not only as tuff as old boots but they're bidirectional too and can be used on AC. In fact, when I was a boy (I couldn't resist saying that!) all this type of unit contained was an LDR and an hot-wire relay. There were no semiconductors at all. The hot-wire relay provided a bit of hysteresis.
Great video as always. I just noticed the Hopi doesn't strobe with the lights out. 😁
I know very little about electronics Clive, but your calming voice and method of description in all aspects of your videos, especially your reverse engineering, is superb (even for a novice like me to grasp, to understand and get the gist of what's going on).
*Your videos are a great stress reliever, believe me, thank you!
🙂👍
That would be OK in my loft to provide an external warning of when I leave the lights on up there.
2:03 I would cut a short piece of extension cord, remove the inner conductors so I only had a jacket. Then I would squirt a bunch of caulk into that sleeve and run the conductors through it, thus making it both waterproof and jacketed. Then run that short cord through a gland and into a junction box.
Thank you Clive, interesting as ever.
I too would have put my money on there being a 555 driving the relay.
This configuration is nearly more simple than a 555 circuit.
Very interesting piece of hardware.
Thanks for taking it apart.
Bought the same item in Greece for 2.60€. I mounted this on a piece of PVC pipe that I sealed with a cap on the bottom. The top of the pipe needed a few turns of cheap electrical tape to get a tight fit. Its been working now for five years with no issues.
Reminds me a bit of the mini photocells that are usually mounted within street light fittings with single core wires coming off it and the actual sensor itself is screwed into a hole on the light fitting
That Hopi in the darkened room has some pleasing Apollo DSKY vibes.
This is incredibly interesting. Does anyone else ever wonder what's happened along our life's journeys to make us so interested in this stuff?
A thirst for knowledge.
The simplest light sensors are the thermal types, with a big LDR and a resistor in series across the mains. The resistor is thermally coupled to a temperature compensated microswitch mechanism. Simple, reliable, and for some reason replaced with relatively complex electronic solutions nowadays.
A 24 V DC relay pulls in (like they all do) at 80% which equals 18 V. The drop out is less standardized, but has to be before the voltage disappears completely. My findings have been anywhere from 2 V to 8 V. Anyway, with exponential charge and discharge, you can usually see different time delays in the two directions. This in addition to what the other component values and ratios cause.
BS7671 requires a sheath over the insulation. The cable doesn't need another layer of insulation. The sheath could be another layer of PVC, but we could also choose to use copper (MICC), Lead (PILC) or steel (conduit).
I have a Turkey-sourced one with a virtually identical instruction leaflet, but with a more rectangular 'dome'. I built it into a waterproof junction box, with a suitably sealed orifice, along with a 12v transformer and the combined unit now powers my 12v patio lights.
BTW, have you noticed that, before the EU, electricians had to be 'experienced', now they only have to be 'qualified'.
“Qualified electrician installer”: ‘handing off the liability buck’.
Hi Clive :) Another fun video. Hope you have a great holiday. Don't shock yourself too much :)
Could be used as-is inside a glasshouse or conservatory.
Or inside a window to control stairwell and corridor lighting in a building, in parallel with a timer
the UV would kill the insulation in a glass House and glass houses are also incredibly humid. Meaning there is likely to be condensation inside it.
@@dfpguitar Very fair point for the condensation and temperature, but regular glass and many transparent plastics do block most UV light, which is why you need crystal tubes for UV sources.
You can't have un-sheathed wiring whether it's indoors or outdoors. The flex on your TV or kettle cannot show exposed brown and blue cables, and neither can cables for fixed wiring such as this. The sheath must be continuous from the appliance to the plug or wiring enclosure.
@@TDOBrandano not disputing that glass blocks some UV, but it is clearly not all , because if it was. All the plants in every glasshouse and polytunnel in the world would die.
Also, there would be no need for UV coatings on spectacles or even welding masks.
this weekend i bought a similar one by amazon for a 24v solar street light project. great!
I initially read the title as 'Simplest duck sensor yet...'
I read dust instead of dusk
@@HeimoVN still at 7 mins. into the video, i thought it was DUST! untill I seen your comment!
It would be interesting to see the CE mark approval paperwork. Since it will have to be recertified to CUK and or CNI next year as we leave Europe the approval paperwork may be more accessible.
Hi BigClive. A quick search of 'tutorial' on your back catalogue revealed nowt, but just so that you know, (you almost certainly already do), you have an amazing voice to listen to. Perfect for online tutorials.
Now there's an idea! Have you ever though about doing online tutorials for beginners?
I suppose it might be a bit tedious for you, but I for one would enrol on one of your courses I'm sure.
I'm an electro-mechanical engineer, but somehow I always felt like I missed out on the whole semi-conductor age. Would love , love LOVE to know more than I do especially if you're doing the tutoring.
Regards Mark in the UK
That switch design with LDR is mainly the first design you could find after the transistor came to market at the end of the '50. And it would have been shot down immediately for the gradual raising of the voltage on that relays, and for that sparking contacts. We miss a thyristor as a clamping mechanism; using that under its clamp current you wouldn't even need to reset the thyristor.
That cap 100 µF 35 V is also to suppress noise. Without it it would make the relays vibrate on any 50Hz leftover.
You have me thinking now, Clive. I have a "Zodion" style, and I emphasize the word 'style' which I bought on-line, and which failed about six months later. It came in box labelled up as "Newlec". I naively took it at face value, and installed it, and was duly disappointed when it failed. On attempting to remove it from the Zodion socket, the opaque dome fell off in my hand! Once down from the ladder, it was clear that this thing was a fake, and a poor fake at that! Under the lid, there was the capacitive dropper, a very sick looking resistor, what appeared to be an LDR, one small electrolytic capacitor and a three legged silicon device. I saw precious little else, though there must have been a rectifier of some sort, somewhere, and I'd guess there was a relay. Granted, this was about seven years or more ago. I may still have it somewhere! When you described yours as the simplest you've ever seen, I swear, you could have counted the components in this fake, on the fingers of one hand!
if I were to find it, would you like to cast an eye over it?
You can sleeve the bundle of wires between a JBox with appropriatle rated flexible conduit. The units would be positioned well out of the reach of anyone accessing it, requiring a ladder and you would isolate the cct before attempting to access the light fitting or JBox.
Zeena warrior princess diode.
I read the title as Duck sensor and was confused...
Read it as Dust sensor, quack-quack, oops.
Me too! 🦆🦆
same here.
...Wabbit sensor!
Yep. Me too.
I used one of these a few years ago for lights in my chicken coop, it was a 12 volt version though but had the same design. The way I dealt with the single insulated cores was to put heat shrink around all three together. Eventually it stopped working, so I replaced it with a new one which still didn't work, and yet the lights worked if I bypassed it. Very odd since the first sensor worked perfectly for a couple of years. In the end I just got rid of it altogether and used a timer to control the lights instead.
You didnt need to worry about single insulated cables if it was a 12v system?
@@TheFool2cool good practice and all that
Double insulated has nothing to do with the insulation on the wires, it means that it doesn't need to be earthed.
Thanks for your intelligent yet humorous opening
I love that you cut the big print out, I don’t know if I’ve noticed that before but I guess most boards you show are square
If these stop working after a year or so, first check to see if it's covered with bird manure. I recommend any outdoors installation have a clear cover over it that can be thrown away when needed, like half a clear plastic soda bottle.
Nice one Clive, it's a simple and classic design.
At 1600 ohms as per the datasheet for the relay, that transistor is going to have an easy life, 22VX22V/1600 ohms = 0.3025 Watts.
Magnetic hysteresis with some help from that diode to ensure the gate current goes away completely during the day.
it's clever, thanks for tip on how to design an enclosure for my temp, humidity and barometric pressure sensor, the traditional designs are a lot of work and the tolerance to driving rain is an issue unless a lot of attention is given to the louvers.
So I am going to make it look like that, with holes in the base for air to in and out past the sensor.
Take care, regards from South Africa.
I can't imagine those tiny surface mount transistors can handle 300mW. Isn't that the limit for the much larger TO-92 packages?
@@eDoc2020 Yes SOT23 packages are like 200mW
At partial conduction with 11V across the transistor it will dissipate 75 mW.
The current through the relay will produce the highest losses when fully energized, during the night.
During the day no current flows through the transistor and then there's a brief period of partial conduction at dusk and dawn.
The zener diode is going to steam a bit during the day with no load on the dc side.
That might get to between 300 and 400 mW.
With the copper around it being minimal I would expect that area to turn brown over time.
They work, it's a cheap item after all, so it's the level of engineering one gets for the price.
Possible reason for the loose wires is that, in would need to use 4 core flex. It is rare to get 3 core in anything other than positive (brown), negative (blue), earth(green&yellow). It would be very stupid to use the earth wire as the output. So that means going to 4 core with an white or grey additional wire. That would be an additional cost and a redundant earth wire
I think this cout be used to great effect for patio lightin and such applications that ta dry to "damp" but covered. Could make a simular unit but replace the ldr with a RTD and use it for the infra red patio heater. Would probably need a 24hr timer for that in the colder months though.
Built some thing like that when i did Physics at School at 13 (1983).
As an aside, it was interesting to compare the Hopi display with the light on and off.
That's all thanks to the camera slowing the shutter down in the dark which gets rid of the flicker on the recording.
I'm guessing that our host did not read the instruction leaflet - it explains that the black bag is for testing the sensor without having to pray for a convenient eclipse.
I think this type of dusk sensor is used indoor, like factories, offices etc.....where there is a skylight used, if the light from the skylight is below the treshold, the electric lights come on. I worked at a place, that used this system to save on electric costs of light, but it was very annoying on cloudy days where the lights are switched on and off multiple times within few minutes.
Thank you. Another interesting video. Just made one of these ldr circuits for the lights for the tree outside our village pub. I was thinking of adding a capacitor to 'damp out' sudden light flashes from passing cars and wasn't sure how to. Would that work?
I love your videos, they are so informative for an old beginner with a very limited knowledge of electronics. I've learned so much. Thank you.
You probably couldn't make a dusk controller for less than buying a complete one from a company like CPC.
it seems to need some hysteresis to keep it from oscillating when the light level is in between
eBay; providing material for RUclips vloggers since 1999.
Great reverse engineering and optimistic use.
Thanks for sharing.
Except that this was from a prominent British supplier.
@@bigclivedotcom Agreed, for a reputable UK supplier this is inexcusable; pretty sure these will be on there soon.
May I wish you a Merry Christmas and and blooming better 2021.
Thanks great tear down as usual.
Heatshrink over the leads would make it somewhat double insulated.... And it would helf against UV light. (insualtion gets brittle over time)... Thats a very simple circuit, which in some form or the other, i have used a lot in the past.
The cable doesn't need another layer of insulation. BS7671 only requires one layer of insulation, but it must be covered by a sheath. Double insulation relates to appliances.
It sounds like a tedious point of terminology, but a cable's second layer doesn't have to have insulating properties. It is there for mechanical protection.
@@westinthewest In some contries its required that cable sheats must resist 1500V.
Neat little thing, thanks for that.
Got one of these from Banggood so it is Chinese. As you say CPC should not be handling it unless it was a 12V version.
Or a 24V DC version.
Need to start giving names to the Impact/Skid Marks on Clive's Desk. Problem is the 1920*1080 XY Origin may keep changing depending on exact Phone position.
Might have to resort to using the somewhat stable BigCliveDotCom as a reference 😁
The single insulated wires could be made quasi-compliant if they were covered in heatshrink and the top sealed with a blob of silicone.
Could be the different ratings in the condensers due to the timing delay needing to be more or less consistent between different devices, so greater "precision" condensers were sourced to that effect? Given that electrolitics have a wide tolerance in capacity generally
0:50 I was like, "oh wow he's diving right into its insides"
Looks like it should be mounted on some sort of pole so the cables go down inside the pole or directly on top above an outside conduit with its bracket slid behind the conduit and attached to the wall. It looks to me to be some sort of conduit sensor with those wires
It's unfortunate they didn't just put some uvb or another type of outdoor sheathed wire on there. Also a gasket between the case and cover to make it usable outdoors.
Alternatively even a larger bezzle so it could mount on a standard light fixture box.
So many possibilities, so few acted upon.
please do a video on the simplest way to wire a snubber to a bidirectional DC motor, including the methodology of determining appropriate diode(s)
With such a simple circuit design, that has no hysteresis or schmitt trigger arrangement, I wonder what it’s performance is like when the light level is very near the switching point. Especially if even a bit of light from the controlled lighting finds its way to the sensor...
I would be interested to see a video off how to take the closeups, the printer and paper you use to produce those clear pics?
Bit of a faff but you could use a bit of Bundy10 and blob of resin on the base, then a gland at the end I suppose.
Oh my word!! I really need to get myself to Specsavers for an updated prescription because I read the intro as a DUST detector and didn't cotton on until you switched off the light. I kept wondering where are the vent holes to let in dust laden air and why on earth would you enclose it in a plastic housing???
Did you notice that the HOPI doesn't flicker when the lights are off? I guess the flickering has to do with the type of light used in the room plus the camera. That is cool though that without the lights on there is no flickering.
It's perfectly safe to use outdoors, so long as no electricity is used... :P
It's like a cheap waterproof coat. 100% waterproof so long as you don't wear it in the rain.
It rather poor that it does not use a Schmitt trigger to drive the relay. Is there magnet or mechanical hysteresis in the relay contacts.
Without this feature, what stops an arc developing across the contacts as they open?
I suspect that hiding the LDR between the other component might have been intentional, as it would limit the source of light to that coming from above, reducing the chance of triggering from say car headlights
The relay tends to open and close fairly decisively.
@@bigclivedotcom I assume this is the result of the gain in the system, however testing with an on/off light source, like a torch, might produce different results to that of a slow sun rise.
Bet you as a kid you used to strip the old yellow road lamps down for the batteries and flash circuit, didn't you Clive???
I’m saying nothing....
Every time I look at the EU power line colours... I think how easy to remember it would have been if brown was for earth brown return a earth potential, and blue was for blue sky hot ... where the lightning comes from. I'm OK with the earth green/yellow.
I wonder if this is a similar circuit to the detachable parking lights you could get for cars in the 1960s?
It was used to turn a red “parking light” on after dusk.
“1, 2, 3, 4, 5. It took about 6 seconds.” lol added a second there
Something seems a bit odd with the schematic. When the LDR is illuminated, the adjacent diode will block it from discharging the timing capacitor. So the capacitor can only discharge via the 47k into the base of the transistor. Which is fine I suppose to make the delay, however the slightest leakage current in the transistor will tend to make it turn on since there is nothing to actively bias it off.
Transistors have a parameter called Iceo which is the collector to emitter leakage current with the base open circuit. Provided this is less than the operating current of the relay then there's no problem. Or am I being naive to assume that Chinese circuit designers read data sheets.
With a bipolar transistor, there has to be enough current flowing through the base multiplied by the gain to allow enough current to flow via the collector to energise the relay. The capacitor will soak up any stray electromagnetic fields, and at 22V, I would not expect any significant leakage from the collector to the base. So it’s fine.
It would be simple to add a length of 14/3 * waterproof line from the guts of the gizmo as long as you needed. That would make the box pass Clive's stringent requirements. I think the gadget would be suitable for North America's 120 V standard as it sits, of course, my understanding of code is a half century old by now. The circuit might supply 22 V even from 120 V.
"Clive's stringent requirements" ?? They're not stringent at all, in fact they're very practical. I believe the code for outside is that it must be housed behind plastic or metal and be waterproof. The only exception I know to this is the double insulated romex made for direct underground installation. Squirrels & rodents will pretty much tear off insulation when given a chance which is only one of a myriad of reasons it's smart to have physical protection for outdoor wires, especially permanently installed ones.
The U.K. requirement is that any mains voltage item/equipment/appliance etc. must have any exposed PVC or rubber cable (meaning any cable outside of the case of an item/equipment/appliance etc.) made of insulated conductor with an outer sheath of a different colour. The line (live/hot) conductor should have a brown colour insulation, the neutral conductor should have a blue colour insulation. Alternatively cables can be run in suitable conduit. If used where there may be exposed to water, then suitable waterproof/weather proofing arrangements should be done, such as rubber seals.
@@Mark1024MAK mmmm. I meant US codes. It's not even allowed indoors anymore, either, because I was told by an electrician my laundry receptable is not up to current code even though it doesn't have a scratch on the cable and no signs of wear. But it does come out of the hard metal conduit and hang down about a foot and half. I don't agree with that but obviously I can appreciate the thinking behind it.
You got me Big Clive I thought the watermark was the ldr for a second and was how the hell does that work lol
Pro-Elec branded items all tend to be Chinese stuff with their brand stuck on it and then just stick in a bit of their own paperwork. I think its pretty much a CPC exclusive or in-house brand.
EDIT: Nevermind, it was in your "Random stuff on my bench." video, at least I'm not crazy... Oh, who am I kidding?
I'm getting deja vu, didn't you already make a video on this exact same unit, where you also mentioned that it'd have to be in an enclosure if used by business owners in case a customer/employee grabs the wires? I'm probably dreaming of Bears with dusk switches again.
Nice one maybe ask curious hvac guy to send you a Honeywell burner control would love to hear your take on it
Ut has occurred to me that you drill a suitable hole in the top of the luminaire to the diameter of the base of the cone. Run some sealant around the lip and job done
That sounds like getting a good long term seal would be difficult. My employer has lots of equipment that is located outside. It’s quite amazing (and very annoying) how rain water can find it’s way in through the smallest of cracks. Even through threaded blanking cable hole ‘bungs’ (blanking caps) [some of the equipment is modular so you can stack them, with aluminium cases with all the holes already made, whether you want them or not].
Even trying to seal them with silicone sealant does always not provide a long term solution 😕
@@Mark1024MAK agreed, and you never want an airtight seal otherwise you will get condensation. As long as it keeps the connections reasonably dry your on a winner.
Ahh it's not a tiny plant pot. Damn was hoping you'd started doing gardening videos. ;)
It's a good job they put the sun in the sky all that time ago. If they hadn't that thing would have filled up with water. :-D
7:15 "fuse-resistor"... is that the same as a magic smoke generator?
I read the title as "dust sensor", and at the half of the video I didn't get what hell is going on here. :D
I thought it was "duct sensor" :D
Fit one to your hoover
...and I made one with only a TL431 setup as a comparator.
Didn't think it could get simpler! I was wrong :(
In South Africa you can have single insulation as long as it's run inside pvc conduit I'm not sure about the British regulations. But perhaps the aforementioned is an option ?
You say the inrush resistor is 100R, but itn't it 10R?
There is another white band after the gold, so the gold is considered a 0.1 multiplyer.
101x0.1 = 10.1R.
Never seen a _white_ tolerance band before though. Maybe I'm mistaken somewhere. Would appreciate any feedback.
I suspect that the gold is the tolerance and that the white band means something else. Primarily because 10Ω or 100Ω resistors are going to be far more available (and hence cheaper) than 10.1Ω resistors... Also a 10.1Ω resistor would be a close tolerance part (better than 2%) , and would cost more than a 5% tolerance part. Can’t say that I’ve seen a white band like that in that position before though.
I'm getting Déjà vu! I'm sure I have seen this video before?🤔
I showed the outside of the sensor in another video and have taken apart a more complicated box shaped version.
Given how it's designed it would be very easy to replace those wires with a piece of cable. All you need is a Philips screwdriver and a soldering iron.
Almost an identical design to one I built in TAFE around 25 years ago
Used a 12V version with a transformer, and made my own in a clear plastic peanut butter jar (with a cable gland) 2015. :-)
If you cover the wires with shrink wrap tubing it will then be double insulated.
Cables only need one layer of insulation.
The Hopi is only flickery with the lights on.
Simple design, reminds me of my first learning with one of those Science Fair kits. I agree on the 1M resistor. I personally like through hole. They should of used multicore flex, but then again this is not something I'd buy to actually use. As with most ebay chinese specials, its good for spares and modifying ;)
That explains why the power consumption didn't seem to change with the relay on or off.
You can almost hear the Zener go "Oh, THANK you!" whenever the relay clicks on... ;)
CPC is awesome, they supply BT most of their sundry items
Their customer service needs improvement. They told me that they are exempt from the Consumer Contracts Regulations because they are a Distributor and not a Retailer.
@@westinthewest Their website would suggest otherwise, so I would badger them about it if I were you.
I've been buying stuff from them for over a decade as a random civilian rather than a business
@@Wanton110 I did tell the nice lady that the Consumer Contracts Regulations state that an attempt to mis-inform a consumer is a criminal offence, but she continued by saying that an LED product (e.g. integrated downlight or floodlight) was classed as a consumable item similar to batteries incandescent bulbs. This was another reason why a return could not be authorised. I had a half-hour conversation that wasn't very inspiring.
Edit:
I opened my account with them in 1989 when they were the local electronics shop in Leeds. I still order stuff from them, but with caution.
Sorry, I read that as "Duck sensor" was really interested for a moment.
Donald and "Duck", What a coincidence!
Didn't you do a video on these a few days back?
Is there a concern that relay could suffer additional wear because it regularly gets partially energized as it waits for the LDR to fully activate?
If anything it might actually last longer due to softer actuation.
I was thinking a continuous low current could magnetize the core of the coil, eventually making the relay stick in the on state.
@@tactileslut Why would continuous low current magnetise the core but continuous higher current (i.e. relay activated) not?
@@ferrumignis That's a good question. Maybe temperature? After dusk it's likely to be cold outside, but if the sensor sits in direct sunlight throughout its days with the coil partly energized (brit:energised) it could be more prone to it. I've had it happen before, which is why it came to mind, but yeah, it's not likely. I probably over-drove my relay, heating the core with a warm coil. I was very young at the time.
Circuit looks like what I used to see in some old electronics project books for dusk sensors. Yet again the Chinese seem to be giving these circuits a new lease on life.
It is a very retro design.
Ive seen this before.. Has it been re-uploaded for some reason...
i thought that too. perhaps there has been some sort of temporal glitch.
I've covered a few dusk sensors.
Looks like something my dad would use, he never cares about safety regulations
I'm sure many of these are in use with exposed single insulated wires.
We just inherited some of my grandfather's things. So many cut-off ground pins (US plugs) and all the halogen lamps were missing their safety glass.
Then again I've built a light bulb box. Three bulbs hot glued in place and all the wiring is exposed, you could easily get shocked using it.
Probably not a whole lot more "legal" but I wonder if one might be able to run those wires through some kind of an insulated or sealed tube to afford them better protection...
I read the title as "Dusk" sensor and was so confused.
I didn't know what a dusk sensor was when I clicked. >_>