A look inside a cheap ebay smoke detector.

You can now buy me cake and things to take apart at:- / bigclive
Part of me was expecting that these smoke detectors might have been fake or just very low quality. But as will be revealed in the video, they are actually quite sophisticated units.
Here's a link to Julian Ilets video of another type.
• Julian looks inside: X...
And the datasheet (on Farnell's website) of the chip that the one in this unit appears to be a clone of.
www.farnell.com...

[@mikeschmidt5228]

my wife uses the smoke alarms for a cooking timer :P :)

[@satibel]

+Mike Schmidt the only time mine beeped was when I forgot my bacon x)

[@mikeschmidt5228]

manaquri lol XD

[@tyvole2387]

+manaquri You forgot bacon? Oh, the shame you must feel...

[@satibel]

Tyvole it was really crispy and smoked a lot, but edible

[@gregoryclark8217]

When I was younger, I used to call the smoke alarm the toast alarm.

[@BrokenHaiku]

You're so calm, give great insights to what you do and just really nice to listen to. Let's face it, you're the Bob Ross of electronics!

[@TrollFaceTheMan]

In reference to what you are saying in the end... That's why a lot of theaters will actually use Both Ionization and Photoelectric detectors in them. They both have their strengths and weaknesses.

[@SaberusTerras]

I had thought at the start of the video that it would either be useless and never go off, or that it would be dodgy construction that could cause a fire on its own.

[@yueibm]

Wow! Thanks for this BigClive! In the US, most smoke detectors are the ionizing type and there have been a few studies that show they don't work well for detecting smokey fires that are generally more lethal than open flames. I've replaced all smoke detectors in my house and in my parents' house with photoelectric ones.

[@drkastenbrot]

"Ioization" might be their name for their photoelectric technology ;)

[@PilotPlater]

Wow that's quite neat. I didn't realize hitting the test button actually tested anything other than the speaker and battery.

[@MrDubje]

+Andy Plater Don't be fooled, that *is* the case with most detectors! If you really want to make sure the thing works, you can get special smoke detector test spray. Do not test them with candles or real fire, as the sooth might have a negative effect on the detector.

[@RFC3514]

+MrDubje - So, not a soothing effect?

[@MrDubje]

RFC3514 Apparently not... Seems to be for this purpose specifically, from what I read. I have my doubts, though.

[@ATLTraveler]

@@MrDubje I test my smoke alarm every time I cook, it works.

[@MrDubje]

@@ATLTraveler It's not a kitchen timer, whahaha

[@Jay-nk7jt]

Clive, i see your still vaping! I've have recently found your channel and find your videos both fascinating and highly educational. As a recently qualified electrical engineer I have learned principals and methods that 7 years in the class room failed to convey. I would love for you to pull apart some of the cheap "box mods" from china for analysis. Either way many thanks!

[@carlzimmerman8700]

Great tear down Bigclive. I'm surprised to see that the chip in this supports multiple synchronized detectors. You pay much more for the ones that have that capability wired up and ready. Makes me consider soldering some phone line between a bunch of these inexpensive units.

[@bummer6]

It got scared when you replaced the IR LED with a regular one... Imagine that every day, you go outside, and at the same time, your best friend on the other side of the street goes outside at the same time, and you wave to eachother, then you go back in. And you do this every day. Now imagine that one day, you go outside, and there is a stranger standing there... Waving....... I'd be freaked out too! Give the sensor back it's friend you monster!!!

[@grendelum]

bummer6 - John Oliver?

[@shivamgagad5674]

LEDs have feelings i guess idk

[@eatyourvegitablespt.262]

HOLY CRAP I CANT BELEIVE THAT THID WAS THE VIDEO THAT KZbin THOUGHT, "SHE LIKES THIS CHANNEL" DARN ME AND MY SMOKE ALARM ENTHUSIASM CAUSE NOW IM SUBSCRIBED TO ONE OF THE MOST INTERESTING KZbin CHANNELS ON KZbin

[@arcadeuk]

I think this one probably surprised us all, it is infact a reasonable bit of kit for the money. I personally buy the ones with the 7 year batteries now, as I get sick of being woken up in the middle of the night by the low battery beeps. I'd be interested to see the capacity of the battery in one of those. I will tear mine down when one dies, but that is sadly a few years away

[@kuro68000]

@Arcadeuk best thing to do is just replace all your smoke alarm batteries once a year, and test them at the same time. A few quid a year to save your life is nothing.

[@arcadeuk]

だれかな。。。 Or buy the 7 year ones and replace them every 7 years :)

[@kuro68000]

+arcadeuk you still have to test them regularly though, don't forget to do that.

[@Bigrignohio]

+arcadeuk Depending upon your area in new construction, or whenever multi-family units are renovated, line voltage units with battery back-up are required (I am talking US as I do not know international requirements). I wonder how long the batteries last in those as the day-to-day power is provided by the line voltage circuit?

[@BenjaminEsposti]

+Bigrignohio Yes I'm from the US and we have line power ones. They also are interconnected, so if one gets set off, they all start beeping. Makes quite a racket, but is more effective in alerting you :P I honestly can't remember when we replaced the batteries. :S We just recently replaced the detectors, because two of them had started to go off on their own. Not only that, they'd go off for a few beeps, then they'd shut themselves off! WTF?!

[@RonSeymour1]

Read any article about the Atomic Kid who tried and nearly succeeded in making an atomic reactor in his shed. He bought loads of detectors as one source of radioactivity. He also obtained thorium from the mantle of lamps and radium from old clock faces. The whole area had to be decontaminated.

[@voltare2amstereo]

neighbour "you alright?" me "yeah why" Neighbour "heard a smoke alarm, thought i'd check b4 calling fire dept" me "no, it was a youtube video"

[@gmcnewlook]

+voltare2amstereo i know a guy that collects fire alarms(like the ones you find in a building so really loud) on youtube, he does his videos when he knows his neighbours will be not home....

[@10010Linus]

my parents reacted this way...

[@Engineer9736]

voltare2amstereo I turned the volume of my iPad down for that reason 😀

[@DragonTamer2345]

I'm pretty sure my neighbors are about to start knocking on my door...

[@alexandersalarms5380]

@@gmcnewlook Um okay? there is a lot of people who do that..

[@ChaplainDaveSparks]

They're selling "disposable" smoke detectors here in the USA. They're powered by lithium cells with an estimated 10 year lifetime. When the battery dies, you replace the entire unit. I guess that's good because the radioactive element has decayed significantly by then. Some people keep replacing batteries not realizing that it's effectiveness has diminished.

[@StefanNuxoll]

California law requires all smoke detectors sold within the state to contain a sealed, 10-year lithium battery to power the device for this very reason. And, of course, since California mandates it you aren't going to find much else :)

[@itmkoeln]

Those are sold in Germany too. Funny thing though, legally required it is to change the battery every year...

[@ChoppingtonOtter]

Chaplain Dave Sparks they are sold in the UK too. Any new build houses are required to have mains powered (with battery backup) fitted though.

[@dercisi9429]

you cant buy a smoke detector with radio actrivity as a normal person, at least in germany, this technology is just for profesonal installers, in very specific cases

[@mrs2691]

Why?

[@kjpmi]

When you bent the LED out of the enclosure it started to beep because it couldn't detect the pulses. The same would happen when the battery runs low I'd imagine, and that was the mode it went into. Below a certain threshold it detects nothing at all from the LED indicating a low battery so it annoyingly beeps until you change it. Could be wrong but just the first guess off the top of my head.

[@QuiznosBear]

I was thinking the same thing

[@RiddimDubstep]

Actually, no. That's why batteries are charged above their claimed voltage. When the battery runs low, the LED would still send pulses but at a lower peak. They most likely have some sort of voltmeter built in to detect when the battery runs below 8.5/8 volts so it will trigger the beeping.

Thanks for finding the datasheet, this was surprisingly fascinating considering it's just a smoke detector.

[@carlyonbay45]

your videos educate me in a subliminal way - often I take a sleeping tablet before bed and I watch your videos that are fascinating and full of information while in bed .....often my eyes will go and fall shut but I can still hear what you say ......and the next day my head is full of words like Nanofire micro henry resistors diodes ....don't know who microhenry is but I feel safe once I know hes there with you and I can sleep easy then ...... your video stimulate my mind with things I wouldn't normally pay any attention to ...so thankyou clive

[@ChaosHusky]

Ever since being a kid, i was always curious about all the detectors that have a radioactive warning on the sensor.. At the risk of exposing yourself to harmful radiation, a teardown of one of those would be awesome! But...just how active are they?

[@bigclivedotcom]

+ChaosHusky That's an idea. They contain a very small amount of Americium dioxide which is a relatively safe alpha particle emitter. But while its radiation can be blocked by something as thin as paper it still poses a hazard if ingested.

[@BenjaminEsposti]

+bigclivedotcom I took apart our old ones that we just replaced, two of them kept randomly going off and then resetting themselves! No idea why, but they are the ionizing type. :P

[@pillowverse7664]

@@bigclivedotcom what happens if it is ingested?

[@swiftproductions4202]

@@pillowverse7664 your chances of getting cancer (especially gut cancer) dramatically increases with a very-very slight possibility of radioactive poisoning since the radioactive element is present in such a trace amount

[@RonSeymour1]

Read any article about the Atomic Kid who tried and nearly succeeded in making an atomic reactor in his shed. He bought loads of detectors as one source of radioactivity.

[@sysghost]

-"Lets just open it..". Indeed. As a famous Australian bloke usually say: -"Don't turn it on. Take it apart!"

[@christopherguy1217]

You are correct, these types will detect smouldering fires faster, the ion ones will detect the rapid burning fire faster. I use both types to cover all the types of fires. The ion ones can have a higher false detection rate and will trigger with very high humidity so don't install them near a shower or indoor pool.

[@mikemike7001]

The first Big Clive video I've found unsuitable for relaxed up-all-night viewing!

[@jayare1933]

going to put this in my watch later... As I'm sure Clive sets it off at least once and it's like midnight right now! On the other hand... SUPRIZE FIRE DRILL KIDS... WHERE DO WE GO! WE HAVE PRACTICED THIS LETS GO!

[@jayare1933]

Story time: So I practice this with them by telling them there is a fire in a rather strange place for a fire to be (when I test the smoke detector) ...One time I said There was a fire in the toilet. My youngest with His smart 3 1\2 year old brain calmly checked the toilet, come back to me and say "Nope, no fire in toilet daddy, you silly." needless to say we all died in the toilet fire of 2017 because we asphyxiated due to laughter and didn't make it out of the house!

[@markh5210]

Most of the UK fire brigades will give residential properties a fire safety survey and fit an alarm for free (this is cost effective compared with having a call out to a fire).

[@SnowmanAndFred650]

As a firefighter here in New Zealand it's a really disheartening that most house fires where there was a smoke alarm but not working or not one at all. We have a partnership with a large retail store to supply smoke alarms cheaply to get them in every home, however the cheap ones like this one do require a 9volt battery and the cost of a 9volt that only lasts 2 - 3 mouths is the reason why people don't have working smoke alarms, and of course false alarms when the toast gets a little burnt is another reason why they ether get taken down to bench level or battery removal. And yes it's a standard for us here that if there is no battery inside it can't fit into the mounting bracket or close up. I recommend getting the Cavius wireless ones, not only do they have a long life battery of 5 - 10 years. Yes the cost of the unit is quite high to buy a lot but it is worth it. You need to have (photoelectric) one in every bedroom one in the hallway one in the lounge and one (heat) in the kitchen. With the Cavius wireless set if one triggers they all will alarm, giving all ocupents of the house time to get down get low get out. House fires of the older times had furniture that was resistant to burning, but in today's modern times and with all this synthetic metrails you only have 3 minutes to get out before the poisones gas's will kill you.

[@d2966-m8t]

Very good testing you did. I bought 6 of them on eBay. I did my own smoke test by burning some leaves from the yard and wave the detectors over the the smoke... No beep, no alarm. No good? These 9v battery holder is on a soft plastic and falls apart quickly, not on a circuit board or a hard plastic. One good thing about them, very cheap, about $2.50 USD each. Why a cheap is good? I am a landlord and have a number of them stolen by tenants.

[@Bob3519]

Never buy a Smoke Detector labeled "For Best Results Hold Directly Over Flame!"

[@GaMMERKitten]

Bob3519 Ha

[@PhilXavierSierraJones]

They are *extremely* good for places where smoke can fill the room slowly (ionization ones detect sharp increase in smoke particles) I have seen laser cutters with smoke alarms similar to this one. (if fan seizes up or vent is blocked or the material catches fire, smoke fills up the room and it sounds the alarm) And pranks. Wire either test button or the sensor (add 1~5K in-line resistor to the Vcc of LED and use transistor) to Arduino or ESP8266 and trigger the thing remotely :)

[@DrRawley]

I have a normal smoke detector that likes to freak out when I play with my Slayer Exciter Coil. I'm not entirely sure why, it's a good 20 feet from where I usually use the coil.

[@bigclivedotcom]

+DrRawley Slayers and other Tesla type coils emit massive amounts of RF energy. They can easily mess with sensitive amplifiers with long sense tracks.

[@DrRawley]

bigclivedotcom Good to know! :)

[@FireDamage]

Get a photoelectric they detect fires better and saved my friends life

[@abyssalreclass]

+Gaming Legends All the ones I have have both photoelectric and ionization sensors. Apparently they are better suited to detecting different types of fires.

[@FireDamage]

averagejoe2843 you are right its best to get both but photoelectric is the minimum you cant just have ionization.

[@simplexicated]

That is very impressive, I wonder if the same chip and basic design is used in detectors which have the BS and or CE marks on them. If this detector was put through all the British Standard tests I wonder if the no battery feature would cause it to fail.

[@ZILOGz80VIDEOS]

Wow, compared to most of the Chinese tat you find, like that big pink bug catcher, this thing is surprisingly serviceable, I could reasonably use this as a smoke detector without worrying about dying in a fire. Could you link the ebay seller you got this from?

[@jkobain]

Just noticed one with no wires coming to it on the ceiling and opened it up. Found a very similar board and a chip without any markings on it; and the chamber is totally the same. Mass production, folks. Mass production.

[@PIXscotland]

A cheap way to get a (low spec) battery too. Quite amazing what's in these £2 items. I wonder if they get bankrupt stock to manage these prices? Surely that can't be manufactured for under £1 even if we exclude all labour costs.

[@webmonkees]

+PIXscotland It is a wonder of economic fringe. Scientific calculator for half a pound, looked up the model and it wholesales for half that. They made a profit, especially with chain stores that can buy in mass quantities. . Perhaps it works from the model of that since it's so cheap, nobody ever returns it, so everything goes out the factory and QA is how many you buy at once to ensure at least one working one.

[@bigclivedotcom]

+PIXscotland It's ultra mass-produced. These things are used in multiples in almost every home in the world.

[@Borednesss]

I just threw my smoke alarm outside last night cause it kept making the "somethings wrong" or low battery beep, and it has a non-removable battery in it. Smashed it to pieces after actually waking up and now I'm off to the store to buy a new one.

[@ollylewin]

Boredness Just like mine. all ended up in pieces.

[@dnb5661]

Do they make them non-replaceable so you have to buy a new one?

[@jendak7921]

Yes. An expensive, nicely designed, very small or something special smoke detector has a non-replaceable lithium battery with a life of 10 years, but it usually left much earlier. The non-replaceable battery is intended to guarantee reliability in that the replacement of the entire alarm affects component wear and dust clogging of the chambers. But there is also a business strategy, because if you have a replaced battery, you can put a new battery every year and use one for 25 years and it still works. I have three with a non-replaceable battery and at the end of its life I will try to disassemble, desolder and find a spare battery in the hope that the chip will restart to clear the memory of a weak battery preventing use once it signals a low battery some have.

[@mankdemes676]

Me: oohhh shit he is gonna put the battery in, (puts volume on 2)

[@GaMMERKitten]

yep

[@DenverJohnBradley]

10 people were wearing headphones.

[@cdcbeauty2582]

14 now

[@itsvoodoo7050]

17

[@mankdemes676]

+Its Voodoo 18

[@StarrBoyVRC]

+Zabradley nice

[@EdgaTv]

+Zabradley 20*

[@UmbreWolf]

that beep you heard after you switched out the LED is a different chirp then the low battery chirp, It indicates degraded chamber sensitivity.

[@ethanpoole3443]

Actually, the best overall general purpose detectors will combine ionization with photoelectric detection as their individual strengths and weaknesses complement one another very nicely. As to which is superior depends heavily on the type of fire, hence the advantage of combining both technologies into a single smoke detector. Photoelectric is more sensitive to a smoky smoldering fire, either just getting started or that is burning poorly. However, ionization detectors respond best to a flaming fire, such as with an established or fast-moving fire or of a relatively clean burning flammable liquids/accelerant fire, which tend to give off much less smoke (where photoelectric then falls short). And in applications where neither is acceptable (high dust environments or lots of false positives) there is also the option of thermal fire detectors, but they are also often the slowest to react (typically looking for a ceiling temperature of 140F+, 60C+), unless more advanced types are used.

[@BrianCairns]

Technically you are correct that combo detectors are best, but the devil is in the details. Ionization detectors suck for smoldering fires. They take minutes longer than ionization detectors to alarm. Photoelectric detectors are slightly worse than ionization detectors for flaming fires. They take several to tens of seconds longer to alarm. Combo units alarm much faster than ionization units for smoldering fires and slightly better than photoelectric detectors for flaming fires. The problem with saying that both detector types are best for some fires is that it ignores the degree. Photoelectric detectors are almost as good as ionization detectors for flaming fires and dramatically better for smoldering fires. Ionization detectors are slightly better than photoelectric detectors for flaming fires, but they are total garbage for smoldering fires. They take minutes longer to alarm and sometimes they fail to alarm at all. Ionization alarms are also much more prone to nuisance alarms. If you had to pick one technology, photoelectric wins hands down. Combo units are fine too, but they aren't much better than ionization. About the only benefit of ionization-only alarms is that they have better battery life. Source: fire.nist.gov/bfrlpubs/fire09/PDF/f09006.pdf

[@sleeptyper]

+Brian Cairns "Ionization detectors suck for smoldering fires. They take minutes longer than ionization detectors to alarm." Ok... :)

[@Bigrignohio]

+Ethan Poole That is where rate-of-rise thermal detectors can step in. They not just look at a set MAX temperature, but also the rate that the temperature is increasing (just like the name suggests).

[@zlotvorx]

+Ethan Poole Too bad the ion source detectors are banned in EU, except for places where they are the only solution (mostly industry).

[@LakeNipissing]

All of the amazing technology in the MC145010 for redundancy checks, and so many people don't bother making use of it by powering it when it needs a 9 volt battery replaced and then die from smoke inhalation in a fire...

[@craggercragger8989]

Interesting video, sir! I honestly, snobbishly, expected this to be a danger to us all. Thank you for dispelling the myth.

[@NightOfTheLiving8bit]

It seems like with this unit...you would need an awful amount of smoke to trigger this thing...given how you blew a large cloud of vaper into it and I'd imagine that even with a light amount of light being disrupted...it should go off...rather than a large plume of "smoke". Then again, it could be that way due to the fact that they're using a very out of date photo light sensing technology and they know it's crap, so they're doing all they can to avoid the thing randomly going off by any light possible. (Then again, a laser pointer normally tricks these things easily). If it was me, and the safety of my house and my loved ones was on the line...I would certainly not cheap out on a smoke detector...but something tells me that if they still manufacture this, it's because it sells...and that's a scary thought knowing that many people have this in their homes.

[@Mark1024MAK]

I don’t have a problem with recommending that smoke alarms be replaced when they are life expired. But there is very little proper research on how long a well maintained smoke alarm will actually last for and still be within specification. In the vast majority of studies, the majority of non-functioning smoke alarms are due to the battery being removed or the mains being disconnected. This figure of replace after “ten years” appears to be a “nice round number” that someone picked. Of course the manufacturers want smoke alarms to be replaced within ten years. But until proper independent research is carried out, we don’t know if the recommended life span should be eight years or fifteen years. Especially as some argue that some types of smoke detectors become more sensitive to smoke when their detection chamber becomes “dirty” or contaminated. And that the semiconductor integrated circuit (chip) used is significantly more complex than lay people are led to believe. See www.farnell.com/datasheets/234450.pdf for details on a typical integrated circuit. I believe rather than just parroting the ten years life that smoke alarm manufacturers want, and then blaming house holders / home owner for not replacing smoke alarms within ten years, we should be pressing the smoke alarm manufacturers to produce smoke alarms that have a operational life closer to 25 years.

[@bigclivedotcom]

They have to allow for dust and oil contamination. It's unpredictable.

[@Mark1024MAK]

bigclivedotcom - that’s certainly possible, but where is the detailed research showing that ten years is an appropriate life? In a ‘dirty’ environment where a smoke alarm is not properly maintained, the life span could be less than ten years. Meanwhile in a clean environment where regular maintenance is carried out, it may be that some smoke alarms may be good for 15, or 20 years. But until proper independent research is done, all we know is that manufacturers tell us “ten years”.

[@bigclivedotcom]

@@Mark1024MAK In some locations just 1 year could already render the unit ineffective. I suppose it makes sense to test them periodically.

[@chrismni8316]

And it is still amazing, how sophisticated some of this really cheap devices are. As long as the Chinese stick to low voltage gadgets, I am fine buying them. Thanks for your great work, Clive! And it had to be said: You are a great engineer!

[@S.C.A.M.B.E.R.]

Have bought this bs smoke detector now?

[@irun4fundotca]

so did you try linking a few together to see if they all go off at once from just one detecting smoke?

[@PaulyRenzeth]

Nah.. That would be an disaster if one goes off and you dont know where its coming from.

[@gl1500ctv]

Thanks a lot!! I played this outside and my neighbors called the fire brigade! 😀

[@EdgyShooter]

Stephen Furr I love how everyone else's neighbors seem to care about their well being, when mine went off all I got was an attempted Noise complaint!

[@dancoulson6579]

Good video. Would have liked to see what happens when you press the test button when the sensor enclosure is sealed, but the IR LED isn't present.

[@bigclivedotcom]

+Dan Coulson It does actually test for the presence of the LED by using super high gain detection so it sees it even without smoke.

[@Gribbo9999]

Clive was the "smoke" you used from your e-vape. I can see how this would work, as it did, for a photo-electric detector but would it also work for the ionising radiation type?

[@bigclivedotcom]

+Gribbo9999 On the basis that I regularly set them off with smoke machines, it probably would. But you have to be careful what you use to routinely test detectors to avoid degrading them.

[@webchimp]

+bigclivedotcom Had an argument with the maintenance guy at work who refused to believe that a shower could set off a smoke alarm, but every time one of the rooms had a shower if the extractor had been turned off it would set off the pre-alarm.

[@christastic100]

as a rule I feel never mix cheap and safety equipment. I have a strong view on this when my parents bosch dishwasher set the house on fire. no one hurt,many thousands of pounds of amage. the circuit board behind the door started it.

[@bigclivedotcom]

+christastic100 I never buy the higher profile brands like Bosch or similar. Their quality is not reflected in their sale price or the price of spares.

[@christastic100]

Yes I believe you are right and the spares are high price .I found Bosch power tools have dropped in quality over the years particularly rechargeable batterys. They dont last andThe replacements are nearly as much as the whole drill plus charger.going back to the smoke detector the optical type are often more expensive in other brands.

[@ChaplainDaveSparks]

An interesting test would be to set up several different models and see which go off first.

[@gregzeng]

Some informed comments here. These very simple, cheap alarms are a quick introduction to more complex units. Different standards operate for different places. One secured housing community had all smoke alarms powered and linked to a central monitoring place. Battery backup (9v battery) was provided. If the battery dropped in voltage, the unit forced open the battery container. This is what I noticed, so I replaced the battery. The central monitoring place should have noticed this too. Not sure why they did not.

[@hal-rekabi6724]

You can test an IR LED by pointing your phone camera towards it and looking at your phone screen. That's how I test my TV remote control

[@manolisgledsodakis873]

Or any digital camera. It's how we engineers check remote control handsets. :-)

[@sadmac356]

Only reason I knew about that was from the Wii sensor bar. I've taken pictures of the TV from my phone, and it picks up the LEDs

[@ADubTheGrizzy]

Damn you are right!

[@over00lordunknown12]

FINNALY! A product that is not a quack product, not a scam, and actually does what it is supposed to do despite the price! :)

[@S.C.A.M.B.E.R.]

It does what it claim but won't work after a week. Garbage AF.

[@BlackEpyon]

These cheap Chinese smoke detectors are so cheap because they use an active LED, where the "normal" ones use the radioactive decay of a small sample of Americium (about 0.2 micrograms). In the case of alpha decay from Americium, the ionized particles charge the air between two electrodes, which smoke will dilute. When the current is less than expected, it triggers the alarm. I imagine that the Chinese one might need it's battery changed a bit more often, though unlike the Americium model, doesn't have it's radioactive output fade over time, decreasing it's efficiency. About 3% of the Americium 241 (half life of 232.2 years) will have decayed into Neptunium 237 (half life of 2.14 million years) after about 19-20 years. This makes the Americium-type smoke detector less effective over time, even if the circuitry were to remain perfect. In America, they recommended that you replace your smoke alarms every 10 years. The question would then be, how reliable are the components in the Chinese LED smoke detectors? Given how cheaply the Chinese components tend to be made, I wouldn't bet on them having a greater lifetime than the Americium-type.

[@tbelding]

This is quite dated, but I thought I'd mention that all of the smoke detectors I've seen, which are all major brands, specify "Heavy Duty" (Carbon Zinc) batteries. (I looked up all the various part numbers they listed on the units). I suspect that it's because the drain is so infinitesimal, you're more likely to have the alkaline corrode than be a benefit. So, personally, I'll continue to put the batteries in that the manufacturer is recommending. (it's time for me to buy some new ones anyway, due to age)

[@ChlorideCull]

Troy Belding You can get 9V lithium batteries. Expensive as heck, but you could probably use it for a good, long while.

[@eamonroad6388]

Heavy duty batteries have a better voltage discharge curve.

[@adaml.5355]

Tell me why I am so addicted to this....

[@imthemistermaster]

pixol you should look up AvE he's like this guy, but Canadian and takes tools apart, did I mention he swears a lot?

[@steve1978ger]

AvE is best at swearing, but even his fans like to switch over to Clive every now and then, until their ears stop bleeding

[@imthemistermaster]

steve1978ger I switch to Clive when I can recite every AvE vidjeo word for word

[@WillyJunior]

these videos really get the dopamine flowing for some reason eh?

[@imthemistermaster]

Bollog Nyessy AvE is my life

[@DarthAwar]

Only ever buy Photoelectric Smoke Alarms (for Bedrooms, Hallways and Common Rooms!) as they give you way more time to escape then Ionization Smoke Alarms also at least in the Kitchen and Garage use a Carbon Monoxide/Dioxide many newer ones can also sense Methane, Natural Gas and LPG/Propane also in a kitchen apart from the gas sensor use a Thermal Sensor Generally 3 to 5 metres away from direct line of sight of the stove or 1 to 3 metres if indirect (but not around the corner from the kitchen!). On a side not always use Surge Protectors on any electrical device even Power Board/Strips that have Surge Protection (as the resettable kind of surge protection take much more time and often have a higher capacity before they trip risking losing your devices!) and especially on Power Boards/Strips that have no Surge Protection of their own which should be illegal internationally. Never trust a Power Board/Strip that does not have an Earth Pin/Plug as if they do suffer a major surge like a lighting strike (As a rare but still very possible scenario!) they will set your house on fire and fry all connected devices even if you have them turned the devices off physically!

[@lezbriddon]

wonder how good the ebay cheao CO detectors are, considering there less than a fiver

[@b1aflatoxin]

I was just about to buy a 5x lot of these detectors off fleabay, but wanted to learn more about 'unbranded Chinese smoke detectors'. Google helped me not. So I tried youtube. I couldn't believe my luck when I saw Clive had a tear-down!!!! :D One of my favorite utubers. I just learned EVERYTHING I was wanting to know! - We'll be buying them now. Supplementing our ionization units with these modern photoelectrics. Bigclivedotcom, you are a gentlemen and a scholar. :) Cheers.

[@S.C.A.M.B.E.R.]

Its been 8 years now. Does your cheap af smoke detector still work? I bet it does not.

[@felenov]

I use the exact same housing for a ESP8266 based temperature / humidity / particle count device that logs everything to a remote server via MQTT. I also made a hidden microphone that transmits on LW bands and draws almost no power

[@tammyhollandaise]

Hey Clive, can you do a teardown of a carbon monoxide detector? I am curious to see what the mechanism of detection is.

[@bigclivedotcom]

Usually an electrochemical cell that generates a voltage based on the ambient CO levels.

[@tammyhollandaise]

@@bigclivedotcom Neat! Thanks, Clive!

[@sicopr2003]

I bought 3 of this cheap ebay smoke detector this week.When i push the testing botton it chirps but when i test it with real smoke it does not.Do you think it will work in a real fire event?

[@MrDubje]

I wonder what's inside the UK made EI mains powered smoke detectors... they also have a battery for when power is lost, and all the mains power supply seems to do is light up a green led constantly to give a quick confirmation that everything is still ok. They can be connected to each other as well via a wire, or optional radio mount plate. They are a fair bit more expensive though!

[@BenjaminEsposti]

+MrDubje I took some apart recently that use the Allegro A5367CA chip. They were older detectors, so no radio option, but they were connected to each other with an extra wire.

[@MrDubje]

+Benjamin ‘Ozias’ Esposti Thanks! The radio coupling is an option you can get if you use another type of base-plate. They come standard with the wired option. I'm talking about the mains powered EI 146 here.

[@DoctorX17]

Both photoelectric and ionizing have their advantages… the best ones are the hybrids that are essentially two detectors in one package, one of each method. Best of both worlds

[@robbieaussievic]

The IR LED would have been visible to the camera wouldn't it ? (Were the overhead lights too bright ?) Another interesting video, Thanks BigClive, mmmm8888888888888 !

[@superdau]

+Rob Robbie The flashes weren't visible for the white LED either. So they are most likely too short for the camera to pick up.

[@Blacktronics]

+superdau at 12:29 you can see it capture the flash partially.

[@SmokiesDen]

Have you checked out the LCD carbon monoxide detectors on ebay? They are $5.73 usd and claim to comply with EN50291 european standard. I have one by my furnace room. Hope it actually works...

[@elchavodel8556]

Is there a way to tell if a smoke alarm has an ionization or optical sensor just by looking inside the chamber? I recently got a smoke alarm for $5 but it has no mentions on which type of sensor it has, not even on it's owner's manual.

[@bigclivedotcom]

It should state which it is. The ionisation units should have a radiation warning label. I only recommend buying smoke detectors from known local sources who have to comply with standards.

[@harl3quinn]

The cheaper ones tend to use ionization. If it's from a reputable brand (First Alert, Kidde, etc.), there should be a (P) or an (i) on the box to indicate if it's photoelectric or ionization respectively.

[@Newty172]

I just got this exact unit without packaging or a battery from china to USA for $2.49USD on eBay.

[@-Gadget-]

1:10 "Let's just pop the battery in here and...... Aaarrrgghh, screw it, let's just rip it apart and see what's inside" 😂😂😂

[@Polite_Cat]

wow, i was really tired, and i somehow fell asleep i think around the beginning of this video, with my headphones on, no less! i did have quite an awful dream about being chased but i think the video must have been over by then. i rewatched it and had no recollection of hearing that beeping noise.

[@xMalhardeshmukh]

Try to avoid the black background,please. The camera can't adjust the white bal and contrast when you flip the datasheet pages.

[@TheMichael769]

I bought an Asda (UK's Walmart brand) own brand smoke alarm about 7 years ago, that had an identical case, though it was an ionization version.

[@planesguineapigs1712]

That is a pretty neat bit of kit

[@mattdude]

In America, smoke alarms are supposed to use a temporal code 3 alarm sound. So despite the price, this still probably wouldn’t be my first choice.

[@Elfnetdesigns]

The fire dept here gives those away free if you go ask for them. The ionisation technology is when the device ionizes the air around the arcing before it sets your house on fire.

[@friendlyfiregaming4601]

Dammit Clive, had no idea you vaped! XD

[@bigclivedotcom]

Just for the gadget value.

[@jhsevs]

Hi Clive, I'm looking for a smoke alarm with a relay output for my 3D printer. Which one of the two types would be the best for sensing acrylic, ABS or PLA plastic vapor?

[@ibiza8426]

bigclivedotcom nice video! Very entertaining and interesting. That chip was well thought out.

[@Gribbo9999]

My smart phone can detect infra-red radiation from TV remote controllers. Would that also work for the Led You removed. You should have turned the lights off to see if you camera picked anything up.

[@LPFthings]

Always thought the ionization type were a lot less sensitive to man-made smoke such as from hazers or fog machines, but not sure how true that is. The optical ones are definitely sensitive to it, but I just don't recall the ionization ones being nearly as bad.

[@dylc413]

I remember playing a show on stage and literally 30 seconds in the place was evacuated, turns out the guys who set the stage up forgot to knock the smoke machine off and triggered all the fire alarms at the festival

[@dylc413]

+Dylan Collins if I can remember correctly they were the photo detectors

[@Drpepper7916]

I`m on the edge of my sofa watching this . . . am I showing the first signs of madness?

[@Andromedan]

At least that actually works! I got an el-cheapo Chinese CO alarm from eBay to experiment with, which had a fake CO sensor cell, so it would never have gone off. (It triggered when I fitted a *real* CO sensor). I wonder how many homes those things are in flashing their little green LED making the owner think they're protected...

[@bigclivedotcom]

+Ben Thomson That's awesomely bad. Which listing did you get the fake from?

[@Andromedan]

There's some stuff over on my blog, including a photo of the box, the listing I got it from has since been removed since I complained about the safety issues. They seem to be pretty generic so I imagine that many of them are actually fakes. CO sensors that contain water instead of Sulphuric acid as an electrolyte don't work too well. They probably don't have any platinum on the electrodes either heh. www.insideelectronics.co.uk/no-brand-ebay-carbon-monoxide-detector/ www.insideelectronics.co.uk/chinese-co-meter-the-sensor-cell/

[@theminicooper]

He didn't explain the potentiometer! :( Looking at the datasheet, i'm assuming it has to do with the sensitivity of the detection? It seems to be hooked up with the IR Detector.

[@katelikesrectangles]

What a lovely chip!

[@zaprodk]

Clive, you need some proper solder wick! Get some Chemtronics 10-100L from your local supplier - You will thank me when you try it.

[@bigclivedotcom]

+zaprodk I somehow managed to mix up my normal good wick and that crappy ebay stuff that requires a flux "boost" to make it work. It's now back in the emergency backup pile.

[@zx8401ztv]

My smoke detector is superb in detecting im making toast :-D, dam thing lol.

[@MrDubje]

+zx8401ztv Now, has that to do with the smoke detector, or your cooking skills?

[@zx8401ztv]

+MrDubje Its the detector, of cause lol :-D I would not even let me get the bread slightly brown before it went mad, i removed it from the celing with disgust, well with a screwdriver lol :-D

[@bigclivedotcom]

+zx8401ztv Strategic positioning is the important things with toast alarms. And keeping the kitchen door shut. You do get alarms that give a chirp before they are about to go off and let you press an over-ride button that mutes them for a short time.

[@zx8401ztv]

+bigclivedotcom At the time i was looking after my mum with terminal cancer, and it made my old mum jump :-(, it was silenced it seconds. I have put it back up and so far its just sat there flashing its green led, i think it remembers the violent disconnection ha ha :-D

[@sleeptyper]

+zx8401ztv Back in the days when i was in a school, our dormatory had very sensitive detectors - they went off even from too misty showering when you stepped out of the bathroom. Funny part of it was that they were automatic as well, so fire dept. visited the complex quite often, especially when school season started and new students arrived. :P

[@digitalsparky]

Just FYI, you can see IR LED via cameras if you're viewing directly on, this may prevent you having to disassemble in the future :). (Unless of course your camera has an IR filter that is :P)

[@digitalsparky]

(I use this technique to check IR remotes all the time)

[@inyquist3175]

Near IR will pass easily through RGB filters in most electronic cameras, so a separate IR-block filter is added to prevent it from desaturating the image. The cheaper ones still let a little through, and it looks like a dim white or purple glow. With that filter removed (say, from a cheap USB webcam), a remote is like a blindingly-bright flickering flashlight.

[@fortuner123]

Incredible for two pounds. Great vid as always. Thanks.

[@jusb1066]

led pulling too much power causing voltage drop?, many smoke detectors are very fussy on voltage and a slight bit of drop will show low battery, annoyingly so. I wonder how long this would run with that cheap battery before its beeping in the middle of the night at you!

[@m1geo]

Watching this at 4am on my mobile phone in bed. The Mrs certainly jumped up in a panic! Oops!

[@zendell37]

This may be a silly question, but do you actually vape or keep the bits around for giggles?

[@newsnowsweden1661]

I bought four very similar ones to this, but they don't detect even heavy smoke. Mine are exactly the same, but with a different layout of the circuit board, and it seems to have cheaper components, like only eight legged micro controller with no identifying text, and there is no potentiometer. But the detector and speaker seems to be the same. So people could be misguided by your video to believe that everyone that looks like yours from china are as good as yours. Maybe you are interested to review one of mine either by me sending photos, or that I send you one smoke alarm? I know that the problem is that mine are not adjusted sensitive enough as yours, because if I put a piece of paper inside the chamber, it starts to beep. Do you think that the potentiometer in yours adjusts the sensitivity of detection of the smoke? I would like to put an potentiometer or resistors to make mine more sensitive, do you have any suggestions how to? Do you have a clue of a similar micro processor with similar functions but with only eight legs? I would like to find a datasheet for it. I guess I could experiment and find out myself, but as I said, if you are interested I could send you photos or even send you one of mine. I really like your videos and I am learning a lot. I am as inquisitive as you, that is why I would like to do find out and fix this, it is not about the money because they cost only about 2 pounds each, as yours. Keep up the good work :)

[@bigclivedotcom]

Can you give me a link to the listing you bought your detectors from?

[@newsnowsweden1661]

www.ebay.co.uk/itm/321735672307?_trksid=p2057872.m2749.l2649&var=511106300803&ssPageName=STRK%3AMEBIDX%3AIT

[@newsnowsweden1661]

I try again: www.ebay.co.uk/itm/321735672307?_trksid=p2057872.m2749.l2649&var=511106300803&ssPageName=STRK%3AMEBIDX%3AIT

[@kurokoshirai9621]

The amount of times my smoke detector has gone off while I'm cooking is ALOT higher than I would prefer.

[@AntiqueMeme]

Spend less time fucking your waifu body pillow and more time learning how to cook.

[@HarryDuBois616]

XPWNZERX what a needlessly rude and horrible thing to say to someone. What's wrong with you?

[@TottyRops]

Hi Clive, may I ask how come you don't use a solder sucker instead of braid?

[@friendlyfiregaming4601]

Really depends on work, TBH. On such small stuff like this, I prefer the braid. But on larger PCB work (capacitors, coils, etc.) I like using the sucker.

[@friendlyfiregaming4601]

That's just me though. Clive may think differently.

[@i-am-art]

no need to shame lead-free solder! it got it quirks but it is also lead FREE!

[@tarbyonlineful]

Looks the same or at least similar to the ones sold under the status name for around £5 in some shops in the uk

[@NSLikeableHuman]

*Note:* do not watch this at night. Especially through speakers. You'll wake up _everybody_ and potentially receive a nice visit from firefighters thanks to those pesky neighbours with their concerns for their property and lives.

[@markusbrandhuber9043]

Really interesting - so I had the right decision to use cheap chinese units for my home alarm system - and yes, I also have real ion smoke detectors at home :-)

[@stridermt2k]

I remember as a boy taking a smoke detector apart and being yelled at by my older brother. -He was concerned that I'd get at the Americium inside. LOL

[@fakeone1083]

do you have a problem with solder-suckers or do you just not have one?

[@johnnyboy3949]

I was expecting this to be chap and shitty, but it’s actually a very good and well made detector. Very pleasantly surprised. Well done china in this one. Now only if all of china’s goods were this well made...

[@skweek256]

Lead solder is the best solder

[@J_Madison]

A lot of current gen cellphones can see UV and/or RF pulses assuming they lack the appropriate filters on the front facing lens. .

[@supergeekjay]

+Thomas Zimmerman CCD based cameras & camcorders have been able to see UV for years. My camcorder from the early 90's sees UV as a flicker, so it isn't just modern ones. Point your TV remote at one and press a button.

[@nasanasa3]

So, Clive, what do you think of lead-free solder? XD