Remote control with mains referenced antenna

When I saw this on eBay I wondered if the chunky brass connector on the antenna was going to be referenced to the mains supply. It didn't disappoint. In the wrong circumstances it can impart a serious electric shock. (Especially if live and neutral are swapped.)
If you have one of these, be aware that it needs to be mounted fully inside a plastic enclosure.
Other than that fairly significant thing, the only other obvious issue is the parallel zener diodes, where series connection would spread the load better. They're also dissipating a significant amount of power. If using this module I would look at changing the dropper cap for a lower value one matched to the real current requirement of the circuit with relay activated (around 50mA). Keeping in mind that the hold current of the relay is lower than the initial pull in current.
If the supply is wired correctly, and the neutral is referenced to local ground, the potential on the antenna socket with respect to ground should be relatively low, but a reversed supply will allow a very high current shock. Basically the live feed, a diode and then you.
I missed one small detail off the schematic of the receiver. The button is wired between a microcontroller pin and the 0V rail.
It was only when I watched the video after recording it that I realised the F and N markings on the remote control are the last letters of off and on. I've never seen that before.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm
This also keeps the channel independent of KZbin's advertising algorithms allowing it to be a bit more dangerous and naughty.

[@kevinsellsit5584]

Thankfully they had the courtesy to gold plate the hot antenna. I mean, if you are going to take a bite from the mains, good continuity is a must at any amperage!

[@kaitlyn__L]

Holy shit, I love “take a bite of the mains”

[@kevinsellsit5584]

@@kaitlyn__L Sarcasm can be difficult to read. I do my best to prevent any confusion ;)

[@funkyironman69]

@@greggoog7559 They probably could have just mounted it inside the plastic enclosure ;)

[@youtubeistyrannical1787]

What most people don't realize is gold is a worse conductor then copper... Only silver is a better conductor then copper. The main reason they coat things in gold is because it does not easily oxidize... Go look it up, it's totally not what you would think

[@kevinsellsit5584]

@@youtubeistyrannical1787 "Look it up". Good words. I began studying metallurgy at age 32 when I bought a mill and lathe for my home shop. I'm 54 now and have learned so much about metal that I realize I won't live long enough to learn 50% of what we already know. That said, Silver is my favorite conductor because it reduces arc transfer when breaking high current connections. ;) Steel (in it's many forms) is by far my favorite metal. Gold is for people who want jewelry more than they want a 1000lbs of misc. mixed metals on a rack in the garage.

[@U014B]

"And the remote control simply goes On, and Off." Actually, the buttons are clearly labeled Activate and Beactivate.

[@meechmushrooms]

Ahh yes, 🅱️eactivate. Good observation!

[@johndododoe1411]

Can't the receiver be set to only accept A or B, then another receiver can use the other button for another big thing?

[@jkobain]

@@johndododoe1411 Clive mentioned that those 24-bit codes divide into the 20-bit part that is unique (sort of) to one RC unit and preprogrammed in the factory, and the other 4-bit part is for commands themselves. So, the short answer is no, it doesn't seem to allow such operation.

[@spacemanmat]

Ah good and Bad

[@HighestRank]

I love the oxymoron of a good portmanteau in the bAM.

[@captianmorgan7627]

We recently had a safety email go out. One of the pump buildings we have was live. The building itself was live. One of the maintenance guys got a shock off the metal door when trying to open it. The metal parts of the building (i.e. most of the building) were somehow connected to power. Never did hear what was the issue that caused it.

[@bigclivedotcom]

That could either have been an unbonded metal frame building, or external equipment finding a current path back to a grounded frame.

[@Azlehria]

Ran into a live panel enclosure a few years ago while tracking down a repeated server failure. That one was a "hilarious" combination of faults. First was the live wire contacting the shell. Okay, it happens. But that was supposed to be a _branch circuit_ coming _out_ of a breaker - so that circuit was being backfed somewhere. Not okay. This was also a subpanel, so it should have produced a direct ground short and tripped the upstream breaker - ground bus wasn't bonded to the panel. Also not okay. Finally, the panel was right next to a floor sink used to fill (and empty) mop buckets! Technically I suppose our ELV license would have allowed us to repair that, since it was clearly "incidental to and necessary for the licensed work", but no. Just . . . no.

[@SalP123c]

Sounds like a pretty cool place to work: death is around every corner and around every metal bannister

[@davelowets]

I found a situation like this once at an airport my company was a contractor at. What I had found was that a motorhead for one of the giant sliding hanger doors was replaced, and was causing the issue. The old one was a "2-phase, 220volt" piece and the replacement that someone had installed in it's place was a single phase, 120volt unit. The installer must have realized the issue of not having a neutral wire, and had connected one leg of the 220volt two phase to the live terminal of the unit, and then connected the unit's neutral terminal DIRECTLY to the metal chassis of the building.. 😳 I found the issue by accident as the door was a slider that parted in the middle and had 2 motorheads on it, one for each half, that drove them. I just happened to be servicing them and noticed that the spec plates on them had 2 different voltages listed, and questioned the maintenance staff about it, and they had no issue why. So I started looking into it, and that is what I found. Thankfully there were no accidents from the entire building being used as a neutral conductor, but it certainly could have ended up as an electrocution in the right situation.

[@Boogie_the_cat]

Well that's a good thing that they used email and not something useful and immediate like a text message. You definitely want to be sure your employees have to wade through dick enlargement spam in order to find out they shouldn't touch an entire building due to Mr. Electron running rampant through the walls.

[@jmargarson]

At least it's transmitting in the 433MHz ISM band, I've had some Chinese RF remote devices that transmitted in the DAB radio band causing interference.

[@TechyBen]

Is that not a kindness to your neighbours, stops them listening to poorly and over cheaply encoded trash. XD

[@After_Tech_Industries]

I had an audio transmitter that did that but with phone service

[@GodmanchesterGoblin]

That's what it *says* it's doing. Without a decent spectrum analyser, who knows...?

[@SolaLupus]

I bet its harmonics cover many other bands anyway

[@bufordmaddogtannen]

Look, a telescopic antenna. It's the eighties all over again. 😁😂

[@bansheemania1692]

FIRST Cordless Phones...what a throwback

[@funkyironman69]

They are fun, can unscrew them and pretend it's a police baton

[@ppheanix]

Wait... is that a cordless phone in your pocket or are you ready in case I fart ?

[@fouzaialaa7962]

clive has acquired a skill that lets him know if a product is designed to kill you or not just by looking at it !!!! Clive !! your the next step of human evolution !!

[@squidcaps4308]

Electrical engineering, tinkering with odd things.. you can learn that skill too. Just open everything you buy, there are patterns you learn. Any metal parts sticking outside from a plastic case that is connected to mains but not earthed = red flag.

[@JR-yl8qi]

"made in china" and bought from ebay is all you need to know XD

[@moonshinepz]

A made in china sticker 👍

[@millomweb]

It's quite simple really - 2 core power lead and bare metal components. I'd earth thant anty enna.

[@rocketman221projects]

@@millomweb If you earth that antenna, the bridge rectifier will explode as soon as you connect the power.

[@johnpossum556]

You should have a BC sticker that says something to the effect of "Identifying shock hazards since 2005"

[@RahulJha-mc6nz]

Paranoid from childhood

[@katelights]

the positions labeled F and N are clearly oFf and oN

[@AAAyyyGGG]

They probably thought "On and Off start with the same letter so let's be clever with our labeling"!

[@fumthings]

also f and n sounds like off and on.

[@LieseFury]

@@AAAyyyGGG I think it's more likely that they assumed the capital O was just an unnecessary symbol.

[@davidaustin3272]

@@gadgetman4494 Except "F" is off, at least on mine.

[@dashcamandy2242]

Foff and Non. Clearly a Google Translate error. LOL

[@MadScienceWorkshoppe]

EV1527 is a classic. Very hackable. It has 4 inputs, and every combination of the 4 inputs sends a different code. I've used it in projects to give a dozen or more buttons.

[@agungpriambodo1674]

Wow

[@davidaustin3272]

I bought a 4-button A/B/C/D version with the same F/N switch and telescoping antenna to control an LED swimming pool light. This was an Amazon purchase in the US. It claims a 1 km range and I thought it might be useful to control other things, but when I received it I noticed it didn't have any of the usual FCC markings. It's pretty easy to get a 1 km range if you don't worry about silly things like regulations. Judging by the amount of noise that comes out of my PC speakers when I press the remote buttons half way across the room, I suspect it may transmit more power than FCC 15.231 allows. I measured the frequency to be 433.92 MHz with a cheap Chinese SDR. For some reason one of the buttons had a slightly different frequency than the other three. My receiver looks similar but it does not have an external antenna, so maybe there is no electric shock hazard. Thanks for doing this, Clive. I did my own tear-down of the light but didn't think to open up the remote.

[@Mayyde]

every time I see you grab that thin red and yellow screwdriver I feel a wee bit more comfy and I cannot explain why

[@mernok2001]

Because its a certified 1000V insulated electrician tool.

[@ItsMrAssholeToYou]

Clive got that old familiar itch And tore-down a shit R/C switch It's antenna block Could give quite the shock A feature that seems very niche

[@cortos_9733]

People need to show some love for this limerick.

[@jkobain]

@@cortos_9733 indeed!

[@javaguru7141]

Wonderful! Its* though ☺️

[@jkobain]

@@javaguru7141 ♥

[@frankowalker4662]

Bravo.

[@RobertMarchini]

In the US, 433mhz is a licensed amateur radio band, and you do occasionally get some naughty devices from China that use 433mhz instead of an unclicensed band (e.g. 315mhz). They’re not illegal, because they’re so low power, they just don’t work at all if you have an amateur radio operator using the frequency.

I think, that the 433 MHz band also is used in Germany for amateur radio.

[@kingsman428]

In the UK 433Mhz is the unlicensed band and sometimes the Chinese send 315Mhz so this is clearly just a mistake

[@davelowets]

They also don't work when you have many devices in operation in the nearby area. My grandfather eventually ended up in a posh "community living center" for the elderly. He was always an electronics geek and had to take his latest "weather station" with him wherever he went. The temperature/humidity probe was wireless and operated at 433mhz. When he was still in his own home, the sensor had always operated properly, and he never had an issue with the display receiving the signal from it. When he moved into the community living center, he had all kinds of issues with the display losing the signal from the wireless sensor. When he questioned me about the issue he was having, he had the sensor just sitting on the brickwork of the building right outside his window. I decided to help him out, and mount the sensor in it's proper bracket, which stands it off of it's surroundings, thinking this will help with his issue, but about halfway through drilling the holes in the brick to mount it I realized that this probably wasn't the issue when I spotted similar sensors mounted outside of just about EVERY OTHER window on the building. Yep, old people must just like to have their weather stations. His unit did have switches inside to change the channel for the communication between the sensor and the display. I changed his channel to a random combination of switches, and he had no more problems with it.

[@agenericaccount3935]

The remote looks like it controls the trap door in an 80s villain's foyer.

[@pear7777]

A remote with a 9v block, that's a first, suppose it lasts for ages.

[@chrisakaschulbus4903]

@@pear7777 "A remote with a 9v block, that's a first" uhm... what about rc cars?

[@pear7777]

@@chrisakaschulbus4903 fcuk, I'm getting denented, did I write that? I looks like it. Nvm, the rc cars run way more communications than an on off..

[@chrisakaschulbus4903]

@@pear7777 everyone can have a little brain fart... it happens to the best of us as well... sometimes when i cook and need to make my sauce tasty, i add honey and mustard and it kicks ass

[@NorthernKitty]

As you mentioned, these are often used to control pumps. It's not uncommon for a pump to be below ground and you wish to control it remotely from above ground. I think they set up the antenna this way so that you could have the relay in a box or chamber below ground, removing that little antenna nub and instead screw on a long cable attached to an external antenna above ground. Still, it wouldn't have taken much to add a removable cap or boot so that the metal isn't normally exposed.

[@cprfenom]

After watching you for a few years with general interest, I am actually beginning to not only follow the schematics, but understand the principles. Great video as always!

[@colinpye1430]

With the On and Off, clearly, the O is redundant. In Canada, where we have both English and French as official languages, the water taps are either labeled H and C or C and F. I’ve often thought it would make sense for them to be H and F (as opposed to C and C), so each language group would get one “good” letter, and the other as “not the good” letter, or something else bacronymed into the situation (Hot and Frigid as an English example)

[@daveys]

Most of these RF switch/smart switch thingies don’t have enough room in them to maintain the double insulation into the box so I’d always advocate putting them into an enclosure anyway. However, the SMA antenna implies that the antenna could be remoted so it’s a fail from me ;-) Excellent teardown as usual Clive, keep up the great work!

[@IvyMike.]

I shall watch this video to the end and things worthy of note, I shall wait patiently for the next video, Thanks Clive, love from Cornwall, UK.

[@graemezimmer604]

The antenna circuit is decidedly odd: It has a loading coil in series (which is redundant if it uses a loaded antenna). And that means that the coax connector is no longer 50 Ohms, so the metal outer is completely redundant and doesn't need to be connected to "Earth" (eg it should have just been left floating). It rather looks to me that the design started life as a 27MHz remote and was clumsily redesigned.

[@ceptimus]

F and N are sensible for oFF and oN. Better to use the last letter of the words than the first - the labels 'O' and 'O' wouldn't be much help.

[@skylined5534]

You know what's more sensible for two tiny words like off and on? 'Off' and 'on'.

[@dashcamandy2242]

They could have done the standardized O and | nomenclature...

[@joshmyer9]

Ironically, the external antenna might even make the reception worse. Those little boards are typically tuned at manufacture, so tacking extra conductor on the end without re-trimming might impact the receiver circuit (assuming this module even has the usual trim inductor). I can also see someone deciding that the reception isn't good enough inside their plastic enclosure, so they install a bulkhead SMA pigtail, bringing that diode-to-mains shell out of an ungrounded case.

[@TheChipmunk2008]

Yes, found the same with quinetic wireless switches here. They operate at an unknown band, but the antenna is a precise length of wire.... adding wire to it or removing any DRAMATICALLY detunes it

[@Electronics-Rocks]

It still has the standard coil antenna which will interact with the exterior antenna. So the external antenna is a gimmick.

[@km5405]

@@Electronics-Rocks its so you can tell its a reallllly good receiver!

[@Electronics-Rocks]

@@km5405 lol

[@davelowets]

Yes, one would need to use shielded coax, and an external antenna of the correct length, for it to work properly.

[@hotmailcompany52]

That little receiver board looks exactly like one of my 433mhz receivers for my Arduino

[@bigclivedotcom]

It's a common module.

[@bleach_drink_me]

How did I not see this months ago? This is one of my favorite kinds of videos you do.

[@MartijnWismeijer]

Anyone else here clicking that like button on any video posted to Clive's channel even before the advertisement finished playing?

[@Spiderelectron]

You get ads? I use an adblocker - works great!

[@samuelfellows6923]

And I have subscribed to KZbin premium for 15£ and don’t see those infernal things 😁

[@tncorgi92]

It's a given.

[@nilswegner2881]

@@Spiderelectron an adblocker is nice on PC but as soon as you watch in the phone app it's ads all over again. Well unless you block ads by blocking them with your DNS server, like do.

[@NiHaoMike64]

@@nilswegner2881 Or install KZbin Vanced.

[@rmx4087]

When I saw the thumbnail, I got the impression the device had melted the plastic bulb. I was a bit disappointed when I learned that wasn't the case. But when I heard the word China, my joy returned.

[@klausdudas]

Assume the F and N labels are for ofF and oN. English is a right-to-left language, right?

[@SonofTheMorningStar666]

Well you can mark it O/O but that wouldn't be really helpful, right?

[@jkobain]

@@SonofTheMorningStar666 how about I/O, what do you think?

[@SonofTheMorningStar666]

@@jkobain Nah. No one would understand that.

[@opif]

@@jkobain ⏽& ⭘ could work, or just ⏻ and let people figure it out.

[@bdf2718]

Stop criticising. They very helpfully marked the LED with "LED."

[@rpavlik1]

These transmitters with otp codes are pretty nifty. I was surprised recently when I got two identical LED floor lamps, and their remotes didn't operate each other, they had those unique codes. Fortunately with a hacked Sonoff RF bridge I was able to read and reproduce the signals for automation.

[@Spiderelectron]

F and N is from a bigger "OFF and ON" switch that has been hacked down to size!

[@mkase4697]

I added a DIY antenna extension to a plug-in doorbell from Amazon (UK) and when testing it, never considered for a moment that it would be at mains voltage. Well, a clean pair of underwear later and I was now a LOT more respectful of my dodgy antenna!!

[@Poop-nu1so]

I always power my antennas with full mains voltage for maximum wireless reception. Also prevents people from touching it... At least twice anyways.

[@Hunter-xy6qq]

Clive, I must admit these video’s are getting juicer each day. 👍

[@piconano]

I bought a $7 SONOFF a few years ago, and really like their design. Upgraded the firmware to run Tasmota. Love it. This is nothing but an old garage door opener chip and easy to hack. Also, the 2W standby power is just ridiculous.

[@Dingbat217]

The tri-state inputs on the back of the remote is so that you can give the remotes different addresses so if you had a lot of them you could make sure they don't overlap.

[@mashamambea5704]

Hey I've been watching your videos for a very long time now and I noticed I've never subscribed wonder how I missed that. Anyway now am in thanks for the very informative content I love them keep them coming.

[@georgeprout42]

Yay for saying PP3! I was starting to think I was the only person that didn't call it a "9V battery" these days.

[@kingsman428]

Even better is a PP9 😁

[@kimsleep4111]

Im not certain why it even needs that stubby antenna, other than to make it look cool. Ive used many of this type of unit, and usually that short spiral wire antenna gets TONS of distance.

[@davidaustin3272]

I have another version of the same remote with 4 buttons for controlling a pool light and changing its color. It doesn't have the external antenna. Still 433 MHz. There is no need for that big 80s-cordless-phone antenna.

[@hadireg]

👍❤Thanks Clive for your great videos.. a well spent time indeed!!

[@andreasu.3546]

That remote looks so 1980s. Reminds me of the toy walkie talkies I had as a kid.

[@sipos0]

"Nice big chunky terminals. That's a good sign." - I feel like the live exposed metal is a much bigger bad sign.

[@Uncle-Duncan-Shack]

Neat, besides the way it gets it's 24Vdc. Touching the antenna connector will brighten your day unexpectedly.

[@creativejamieplays7185]

The crazy thing is, just yesterday I ordered a 12v remove relay with exactly the same control. The unit I have has one of those little pin connectors so you can move it for different modes. 1 mode is A- on and B- Off. 2nd mode is A- On A- Off B-Nothing. And if you take it out all together its just A-On until released. I am using its bits along with another external relay to make a buzzer to say when power goes off.

[@mattelder1971]

Thank you for that info. I've been trying to figure out how that damned jumper worked!!! The Chinglish in the product description on Amazon was no help at all.

[@creativejamieplays7185]

@@mattelder1971 you had instructions? :O. I just did trial and error.

[@CraftMine1000]

Other than the live antenna I'd say this was decently designed, very nice pcb!

[@nonactiveemail8141]

Another great Video from Clive👍

[@alpcns]

"A" and "B". Activate and (then) Burial.

[@charliegordon5085]

738K subscribers, congratulations 🇨🇦

[@serversurfer6169]

_“This chip isn’t powered until you press the button. Very strange…”_ I don’t really know about this stuff, but isn’t that why/how it draws no current while idle? 🤓🤔🤷‍♂️

[@bigclivedotcom]

It's the way they did it that was odd. But subsequently turns out to be a datasheet example.

[@janosnagyj.9540]

@@bigclivedotcom Maybe that controller doesn't have sleep or low power mode... which is still odd for a mostly battery-operated ASIC... but they solved it with this workaround. It's much more difficult to do this hack on silicone level :)

[@MostlyInteresting]

On newer MCU's this hardware wake up circuitry is built in. Just tickle a pin and it will wake up and do a thing and the go back to sleep.

[@Agent24Electronics]

@@janosnagyj.9540 Impossible, I'd imagine, to hack it with silicone... :P

[@MrBBea4]

I'm torn between strange and an old-school brilliant way to save that poor old 9v battery as there is no "idle" state. Other then the slight "parasitic drain" this thing draws next to nothing when the buttons are open. Just enough to cause the battery to leak out in a few years of being lost behind the couch. Reminds me of my first TV clicker, back in 1970's-something. Way to go China, always pushing the curve in engineering advancement

[@PeterShipley1]

The two amplifiers in the remote are probably also there to reduce harmonics when transmitting. Have you considered using a rtl-sdr dongle to get RF samples? It would be some a trivial to sample and display the bit pattern code. Since this transmitter uses on off AM style you'll be able to see the pattern just by looking at the waveform. I would suggest using the rtl_433 program, it has a feature to use display the raw and demodulated waveform with timing.

[@HiddenWindshield]

It's possible that the "F" and "N" on the transmitter switch are short for "off" and "on", but since they start with the same letter, they just used the second letter of each word.

[@jkobain]

OG [I/O] doesn't do it anymore?

[@carpdog42]

@@jkobain I always thought I/O was odd. If "I" means current then what is "O"? If I is a pictogram of a bridged circuit, then O is.... huh a loop? Is I a pictogram and O just stand for "off"? One way or another its a broken abbreviation or metaphor.

[@boulder795]

@@carpdog42 I=1 O=0. 1 is on, 0 is off

[@mattelder1971]

@@boulder795 I'm amazed at the number of people I encounter that don't understand this. I guess growing up in the age of the 8-bit microcomputers and learning about binary very early on, it just makes sense to me, where people who have never really dealt with binary are totally confused by it.

[@stevenspmd]

If it was meant to be enclosed in a box then why is the antenna exposed? Seems like what you really have there is a wireless taser :-)

[@NorthernKitty]

I believe so that you can run an antenna cable. For example, imagine this relay is in a chamber deep below ground and you want to control it remotely from above ground. You could then run a conduit for an antenna so you'd be able to receive a signal from above. Still, they could easily have made a removable cover or boot as a safety precaution.

[@davidmcgill1000]

@@NorthernKitty Which sounds like a great way to cause radio interference thanks to its unique "feature".

[@PeterShipley1]

I'd like to see how the design would be fixed

[@therealjammit]

Why didn't they at least separate the RF ground through a 1pf capacitor?

[@colejohnson66]

That capacitor being removed saves a penny!

[@eDoc2020]

That's how it was done on hot chassis TV sets.

[@davidfaraday3085]

Indeed it was, though the capacitor values were usually a lot higher than 1pF. At least for the older sets that needed Band 1 reception (40 - 70 MHz) the capacitors would typically be 1nF, (or .001 microfarad as it would have been described at the time). These capacitors were also usually shunted by a resistor, typically 2M2, to discharge them.

[@Roflcopter4b]

@@eDoc2020 And many tube radios back in the day. Though they sometimes didn't bother with the capacitor for those too, leaving the chassis connected straight to the line (unpolarized plugs back then, so 50/50 chance to have a live chassis). Even when there was a cap, they almost invariably short over time. Fun stuff.

[@afeathereddinosaur]

This piece of equipment could be quite the shocker, eh? Truly a Beast from the East

[@heyarno]

Perfect, even with live and neutral swapped for maximum shockage :D

[@MrBrianms]

Cover the exposed antenna with a thick plastic housing. Then it would pass. So near to a great design. Zapp! Brilliant video. Thanks.

[@nutsnproud6932]

The way the transmitter switches power the IC via the transistor keeps the quiescent current super low. It is for long battery life.

[@BG101UK]

I've heard of an "active" antenna, but this is taking the biscuit! Live transmission coming soon? ☺

[@TheSpotify95]

Lovely! I love it when we have parts that are easily touchable, that are live at full mains voltage :). In fact, you could add an external antennae to it (which is more powerful/more directional). Would that not make the antennae live?

[@AintBigAintClever]

I just got a similar unit from Amazon through the Vine programme. The antenna shield on this one is wired directly to neutral, so it's getting a nice PAT fail photo for the one star review.

[@BitwiseMobile]

I remember when I was an avionics technician in the Navy they told us that even 100mA can be fatal in the right conditions, so 75mA is going to give you a decent shock.

[@kevinmartin7760]

If the zener voltage has a positive temperature coefficient they will tend to balance out. The one with initially lower voltage will conduct more and warm up more, thus reducing the voltage imbalance. It will not balance perfectly, though.

[@punkrockllama]

I wonder how many of these eBay or wish things are factory rejects. Like they made up a batch with the wrong stickers and decided that it was better to just sell them cheap than put on a new sticker or dump them. I've seen it with like chef knives. It's pretty smart.

[@AgentLokVokun]

Keep up the great content

[@rockinghorsesciencemechani6020]

Love your videos big Clive. I wish I had your understanding of electronics. Jealous

[@ThePoxun]

You know what video I'd really like to see... something demonstrating the issues with these mains referenced exposed metals... something maybe starting with an oscilloscope and ending with some bangs and flashes and maybe a hotdog or two for human finger substitutes ;)

[@chrishartley1210]

Programming modes for these remote switches are often momentary (single button), continuous (while single button pressed), toggle (single button) and on/off (two buttons). I can't see that momentary would be much use in a switched relay configuration though.

[@jlucasound]

Clive said "Here we go" and then "There we go". I was running back and forth. But he did get that remote open quite smoothly. ;-)

[@simontay4851]

You could easily put some heatshrink over the exposed metal of the antenna.

[@capnskiddies]

KZbin says you've commented 2 minutes ago. I came to the comments 10 minutes ago to find this comment.

[@philmerrifield1163]

Yet another live item from China lol I bought a set of mains powered lights from China just before Christmas and got a zing off it, 1 diode between you and certain death 😁love your vids mate stay safe and sound in these very uncertain times

[@zeekjones1]

Me: picks things up by the antenna. Also me: checks live wires with fingers. Also me: has abnormally high skin resistance. Looks like fun. I somehow want to buy this more.

[@bigclivedotcom]

Don't really on your high skin resistance to much. Water makes a huge difference.

[@zeekjones1]

@@bigclivedotcom Good thing I'm always dehydrated... . Jokes aside; I do take due precautions, only messing with known values. Although as a kid, how I learned of my resistance... I was the kid who put a finger in the light socket, and switch contacts, and plugs... Probably why I got interested in electricity and electronics.

[@AiOinc1]

The "N and F" positions, my guess has to be they just took the last letters of On and Off and stuck them in the side. maybe they don't know I/O yet?

[@misterhat5823]

The only reason I can think of for the PNP switch arrangement in the remote is so the input is not pulled above Vcc. With this arrangement the inputs are a diode drop below Vcc (minus Vcesat which shouldn't exceed ~100mV). Using a diode to power the chip puts the inputs above Vcc by one diode drop. A lot of chips gets very upset (and even fail) when an input is driven above Vcc.

[@felenov]

Chinese engineering has met our expectations this time. Great device

[@Umski]

I do like that telescopic antenna'd remote - looks like an evil villain's A for Activate, B for Boom type of accessory :D

[@tubastuff]

I can (sort of) see the logic in the parallel zeners. If one goes open, you still have one to hold the rail to 24V, otherwise, the voltage might go very high. This would not be the case with series-connected zeners.

[@AntzWilkz]

Cut the ground and signal lines to the antenna and put 220pF Y type caps in both paths. It will still work and it will not be a shock hazard anymore. It was a method Phillips use to use in their TVs.

[@uzaiyaro]

Hey Clive, in a newbie to electronics, and I would absolutely love a video on how you go about reverse engineering stuff, and maybe some recommendations of stuff to buy to have a go at reversing something yourself. I'd love to get into it, but have no idea where to start. Thanks!

[@enginebeer6755]

Excellent stuff, enjoyable, thanks. Why not break the antenna track and solder a 20 or 100pF capacitor so the antenna is not live?

[@chris1newbury]

i like that, its nice and sturdy but with just the right amount of danger

[@Rollmops94]

I love these videos.

[@WarpRadio]

to add a few items (which Clive mentions the pick up coil), the RF section: on the receiver side, there appears to be a small "pickup coil" which will allow the thing to be operated without the external antenna connected.. it may have been an after thought to add the external antenna; they COULD have isolated the external shield on the RF connector with a pair of 20 pF ceramic caps to the common of the circuitry and this would have isolated the mains from the exposed metal parts of the antenna circuit.. On the transmitter side: this appears to be a "saw resonator" type RF circuit.. quite similar to a "garage door remote control" though slightly-modified with a buffer amp and external antenna.. the rest is as expected. Overall, from the RF side of things, this is a POOR quality RF link.. I would think this has a effective range of maybe 1000 feet outdoors, 'line of sight' (much less range indoors).

[@vargasantonio286]

Capacitor Dropper is used because it is simpler and cheaper but a potential hazard. Some models from other companies have switching type power supply.

[@bigclivedotcom]

With unisolated buck regulators in some.

[@moseskioko1299]

You videos are amazing

[@bbowling4979]

So how do you decouple the exterior casing of the antenna from the mains supply in a design like this?

[@amojak]

a low value capacitor in series with both legs on the board to be safe. something like a 100pf or less would be a short at 433mhz but not let through any AC mains.

[@gavincurtis]

Mount one of those locking thermostat boxes over it.

[@caramelldansen2204]

throw it in the recycling and buy a safe one.

[@amorphuc]

Thanks Big Clive. Very cool.

[@ukaszlipski8347]

That 680v MoV is interesting. If you are about to design capacitive drop power supply look up „ tdk everything for capacitive dropper”, very usefull stuff, also „cap drop offline supply texas instruments” or „AN954 transformerless power supply”

[@SaNjA2659]

Not bad! Very nice design inside the remote, ensuring that nothing trickles the battery down with its quiescent current. At this point I'd guess the function of the switch is more to prevent accidental button presses rather than help with battery life. As for the antenna (which, as someone has already pointed out, appears to be incorrectly wired to an existing internal antenna), an easy fix would probably be to swap the diode bridge for a half-bridge rectifier. This would ensure the antenna is always referenced to Neutral, which although not ideal, at least won't shock you under normal circumstances.

[@simontay4851]

Capacitive droppers don't work with just a single diode half wave rectification.

[@SaNjA2659]

@@simontay4851 You're right, my bad... A couple of back-to-back 24V zeners strategically placed after the 68 ohm resistor would help, but that'd probably dissipate too much power. Edit: or rather a zener in series with a regular diode.

[@bigclivedotcom]

You also have to allow for miswiring or unpolarized plugs.

[@SaNjA2659]

@@bigclivedotcom Yeah, as I said, not really a proper solution... Still better than guaranteed 300V pk-pk on the exposed part. On the other hand, in case of miswiring you'll get full 600!

[@chrisglover1978]

Could you measure the voltage between the attenna and earth? Would be interesting to see what was actually there

[@mrahob275]

Looks more like two different resonance coils for the two options of freqs .. on the remote anyway

[@67martinyoung]

Deep, really deep. Love it.

[@jkobain]

Wow, the title is already so promising!

[@linuxguy1199]

17:50 The two transistors aren't a "buffer" its to get a resonably high power output, ima guess from the transistor size proabably 500mW

[@keithking1985]

that little daniu transistor tester you have can show you the code from remotes like that and tv remotes etc. i wreaked mine by connecting it to a charged capacitor by mistake. Anyway! nice video.

[@colinedwards7250]

It's likely that those coils in the TX are part of a frequency multiplier, as the crystal won't be directly 433Mhz. Also the aerial socket would be even more exciting if L & N were reversed, as in countries where they are not polarized. A small value cap in series would solve the problem, without effecting the RF.

[@stuartmcconnachie]

@3:46 Wait until it’s dark. Put the light in the window?

[@ssgeek4515]

Looks like a sma size Arial connector to me. Why is the outer grounded. It's only recieving. Does it need a ground. Tell China please.Great breakdown Clive.

[@johnmorgan1629]

Wonder if you could get this to control the charging of one of those death Daleks torch lights you covered a while ago, then you'd have two potential shock hazards.

[@The.Plague]

Well, they are both negatives. So if he could get them to multiply he would have something positive.

[@JendaLinda]

They could put two capacitors in series to the antenna connections. Those would let RF through, but they would block mains frequency.

[@gianlucalocri]

I was thinking the same but maybe a better solution is to use a small RF transformer. I've seen some of those in the past. They are small and I think in general there is less risk to dielectric brakedown with respect to caps... It's a shame because the circuit seems to be well designed (better than the eBay Chinese electronics average)

[@killcar5nbike2]

Blocking capacitors on the mains to exposed parts used to be a thing. They got nicknamed "death capacitors". Any exposed parts has to be fully insulated. Electronic parts can short, and things get wired up wrong. Nothing should ever be "made safe" by trying to Isolate it with an electronic component in series with the mains.

[@JendaLinda]

@@killcar5nbike2 This should be the kind of capacitors, which are used in switching power supplies between primary and secondary side.

[@killcar5nbike2]

@@JendaLinda they are earth connected surpression, not connected to the line. No device with any external conductive components or user made connections can be referenced to the incoming line.

[@JendaLinda]

@@killcar5nbike2 Look at any USB charger. There's no earth connection. The primary is referenced to mains and it is connected via a small capacitor to the secondary.

[@dhaen]

The mystery for me is the 433MHz crystal. They don't normally go up that far and high frequency ones would be expensive. I wonder if they are using it on a high overtone. I've used crystals up to 9th overtone successfully.

[@ObiwanNekody]

Thank you for sharing this!

[@michaelhorton6166]

ofF and oN maybe?

[@wich1]

Better than Off and On I suppose

[@pear7777]

@@wich1 simple 1 and 0 would have sufficed.