Remote control with mains referenced antenna
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- Опубликовано: 2 окт 2024
- 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.
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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!
Holy shit, I love “take a bite of the mains”
@@kaitlyn__L Sarcasm can be difficult to read. I do my best to prevent any confusion
;)
@@greggoog7559 They probably could have just mounted it inside the plastic enclosure ;)
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
@@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.
"And the remote control simply goes On, and Off."
Actually, the buttons are clearly labeled Activate and Beactivate.
Ahh yes, 🅱️eactivate. Good observation!
Can't the receiver be set to only accept A or B, then another receiver can use the other button for another big thing?
@@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.
Ah good and Bad
I love the oxymoron of a good portmanteau in the bAM.
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.
That could either have been an unbonded metal frame building, or external equipment finding a current path back to a grounded frame.
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.
Sounds like a pretty cool place to work: death is around every corner and around every metal bannister
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.
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.
Look, a telescopic antenna. It's the eighties all over again. 😁😂
FIRST Cordless Phones...what a throwback
They are fun, can unscrew them and pretend it's a police baton
Wait... is that a cordless phone in your pocket or are you ready in case I fart ?
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 !!
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.
"made in china" and bought from ebay is all you need to know XD
A made in china sticker 👍
It's quite simple really - 2 core power lead and bare metal components.
I'd earth thant anty enna.
@@millomweb If you earth that antenna, the bridge rectifier will explode as soon as you connect the power.
You should have a BC sticker that says something to the effect of "Identifying shock hazards since 2005"
Paranoid from childhood
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.
Is that not a kindness to your neighbours, stops them listening to poorly and over cheaply encoded trash. XD
I had an audio transmitter that did that but with phone service
That's what it *says* it's doing. Without a decent spectrum analyser, who knows...?
I bet its harmonics cover many other bands anyway
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.
Wow
the positions labeled F and N are clearly oFf and oN
They probably thought "On and Off start with the same letter so let's be clever with our labeling"!
also f and n sounds like off and on.
@@AAAyyyGGG I think it's more likely that they assumed the capital O was just an unnecessary symbol.
@@gadgetman4494 Except "F" is off, at least on mine.
Foff and Non. Clearly a Google Translate error. LOL
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!
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!
Assume the F and N labels are for ofF and oN. English is a right-to-left language, right?
Well you can mark it O/O but that wouldn't be really helpful, right?
@@SonofTheMorningStar666 how about I/O, what do you think?
@@jkobain Nah. No one would understand that.
@@jkobain ⏽& ⭘ could work, or just ⏻ and let people figure it out.
Stop criticising. They very helpfully marked the LED with "LED."
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.
You know what's more sensible for two tiny words like off and on? 'Off' and 'on'.
They could have done the standardized O and | nomenclature...
every time I see you grab that thin red and yellow screwdriver I feel a wee bit more comfy and I cannot explain why
Because its a certified 1000V insulated electrician tool.
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)
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!!
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.
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 :-)
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.
@@NorthernKitty Which sounds like a great way to cause radio interference thanks to its unique "feature".
I'd like to see how the design would be fixed
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.
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
It still has the standard coil antenna which will interact with the exterior antenna. So the external antenna is a gimmick.
@@Electronics-Rocks its so you can tell its a reallllly good receiver!
@@km5405 lol
Yes, one would need to use shielded coax, and an external antenna of the correct length, for it to work properly.
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.
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.
"A" and "B". Activate and (then) Burial.
The remote looks like it controls the trap door in an 80s villain's foyer.
A remote with a 9v block, that's a first, suppose it lasts for ages.
@@pear7777 "A remote with a 9v block, that's a first" uhm... what about rc cars?
@@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..
@@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
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.
I always power my antennas with full mains voltage for maximum wireless reception. Also prevents people from touching it... At least twice anyways.
F and N is from a bigger "OFF and ON" switch that has been hacked down to size!
Why didn't they at least separate the RF ground through a 1pf capacitor?
That capacitor being removed saves a penny!
That's how it was done on hot chassis TV sets.
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.
@@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.
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.
"Nice big chunky terminals. That's a good sign." - I feel like the live exposed metal is a much bigger bad sign.
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.
In the UK 433Mhz is the unlicensed band and sometimes the Chinese send 315Mhz so this is clearly just a mistake
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.
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.
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.
So how do you decouple the exterior casing of the antenna from the mains supply in a design like this?
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.
Mount one of those locking thermostat boxes over it.
throw it in the recycling and buy a safe one.
Neat, besides the way it gets it's 24Vdc.
Touching the antenna connector will brighten your day unexpectedly.
_“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? 🤓🤔🤷♂️
It's the way they did it that was odd. But subsequently turns out to be a datasheet example.
@@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 :)
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.
@@janosnagyj.9540 Impossible, I'd imagine, to hack it with silicone... :P
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
F=of*F*; N=o*N*? :)
Wouldn't be the first time I've seen English text in reverse on a product from China!
Good call... i would bet a small sum you are right. At leas they weren't labelled O and O
@@TheChipmunk2008 I later realised that it might not be due to English words being *reversed* - they might have decided that labelling the switch "O" and "O" was silly, and so just *used the next letter* for each word.
Thus it would be "oFf" and "oN".
We may never know :)
F=Functional
N=Not Functional
@@PowerScissor he said the 'N' was on, so I'm gonna say, if that is the case, it's probably more like 'f*cked' and 'not f*cked
@@the_clockwork_jackass6897 My china remote I use for my workshop 220v dust collection system has an N / F also...except it's backwards from the one Clive has.
That's how I remember it in my head. I guess mine is labelled backwards. I've just marked over it with red and green anyway.
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.
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.
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.
@@mattelder1971 you had instructions? :O. I just did trial and error.
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).
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.
Don't really on your high skin resistance to much. Water makes a huge difference.
@@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.
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?
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. ;-)
Anyone else here clicking that like button on any video posted to Clive's channel even before the advertisement finished playing?
You get ads? I use an adblocker - works great!
And I have subscribed to RUclips premium for 15£ and don’t see those infernal things 😁
It's a given.
@@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.
@@nilswegner2881 Or install RUclips Vanced.
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.
Put some shrink sleeve on the exposed metal antenna part... sorted. :)
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
People need to show some love for this limerick.
@@cortos_9733 indeed!
Wonderful! Its* though ☺️
@@javaguru7141 ♥
Bravo.
This piece of equipment could be quite the shocker, eh? Truly a Beast from the East
RF codes......
A friend of mine went out to lock his car. When he came back in, I told him his wireless doorbell rang as well !
One time my mother was in a store parking lot, every time she unlocked her doors, they locked soon afterwards. She was ready to call me and ask me what the heck was wrong with the car, but then she looked over at a woman in the next aisle staring quizzically at her remote and car. Every time my mother unlocked her car, she unlocked the other lady's car... Meanwhile, the other lady kept locking her doors and wondering why they kept unlocking by themselves.
I guess it was bound to happen, Chrysler/Dodge minivans are very popular, and there's only so many code variants programmed by the factory.
@@dashcamandy2242 Begs the obvious question - were the keys the same as well ?
@@dashcamandy2242 the remote for my 01 VW Passat would work on my wifes 00 Passat. (Unlocking and locking both cars)
My remote start would start the BMW across the street as well. Pretty fucking funny.
Another fun fact. The Crown Victories used for Law Enforcement only had about 9 different key cuts. Its not uncommon to find yours will start many others
I was involved in commissioning half hourly metering on a site. A pricey wireless data transmission system had been specified for some remote meters. The cheapskate electrical contractors had substituted their own home brew system. A few months later i was contacted by a government inspector, this transmitter alongside a manhole in a car park was jamming out car remote control fobs. Turned out the electricians had soldered the meter pulse output reed switch across the button contacts of a remote fob which would then close a relay in the receiver unit. If the meter stopped with the magnet adjacent to the reed switch, the transmitter would transmit continuously and jam out car remote controls!
All the good stuff that comes from 'China' was designed in Taiwan. Or the US.
You could easily put some heatshrink over the exposed metal of the antenna.
RUclips says you've commented 2 minutes ago. I came to the comments 10 minutes ago to find this comment.
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 ;)
To be fair, provided the Live and Neutral have been connected correctly the voltage on the antenna is only -24V so if you get a zap from it then it's your fault for wiring it wrongly.
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.
OG [I/O] doesn't do it anymore?
@@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.
@@carpdog42 I=1 O=0. 1 is on, 0 is off
@@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.
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?
Chinese engineering has met our expectations this time. Great device
ofF and oN maybe?
Better than Off and On I suppose
@@wich1 simple 1 and 0 would have sufficed.
F and N are the last letters of on and off, words that both begin with the same letter O
It is strange that they didn't just put a small capacitor in series with the antenna connection. That would limit mains frequency current if you touch it to a very low value while letting the RF through. When TVs had circuitry running directly off the mains the aerial inputs had just such capacitors.
@3:46 Wait until it’s dark. Put the light in the window?
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.
Looks more like two different resonance coils for the two options of freqs .. on the remote anyway
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.
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.
Well, they are both negatives. So if he could get them to multiply he would have something positive.
It's such a shame. It would be easy to make it safe by coupling the antenna, via a transformer, or a couple or capacitors. If the board could be rearranged, it might be possible to print the transformer or capacitors on it, as they only have to be small to pass 433MHz.
That little receiver board looks exactly like one of my 433mhz receivers for my Arduino
It's a common module.
👍❤Thanks Clive for your great videos.. a well spent time indeed!!
Yay for saying PP3! I was starting to think I was the only person that didn't call it a "9V battery" these days.
Even better is a PP9 😁
Perfect, even with live and neutral swapped for maximum shockage :D
I've heard of an "active" antenna, but this is taking the biscuit! Live transmission coming soon? ☺
Made from the finest Chineseium.
It is not strange it is quite in genius using so few components to do so much. In effect it only turns the system on when a button is pushed, It is tyoical ols school OOK, (on/off keying).
I saw similar remote and instead of microchip it had that panel with tinny little switches with numbers that you can program manually to match receiver. I found out after some playing with it I can set it to turn on/off pool pump of my neighbor house :D
In the past people built binary code counters to scan through every address.
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.
It's a orF and orN switch.
Your voice is relaxing late at night, keep talking to me Big Clivey 😉
That "little antenna" is a simple RF low pass filter. It not part of the receiving antenna due to too being connected at both ends, and the ground plane surrounds the antenna connection, helping to separate it from the main antenna. Because its unshielded, it can serve as a very weak antenna when the main antenna is disconnected. It can also serve as a loading coil for the antenna due to the antenna is way too short for 400MHz use. Its been years sense I did antenna/RF theory work, so some fine points I may be wrong on.
That remote looks so 1980s. Reminds me of the toy walkie talkies I had as a kid.
Putting some heatshrink or self bonding electrical tape over the antenna is also an option.
Also the z-diodes should be behind the 51 ohm resistor. Something is wrong here...:)
BTW z-diodes in parallel? if there is no other way? use a resistor in series for each one to balance the current flow.
You could just use 2 capacitors on the antenna circuit a few pF would provide sufficient coupling @ 400Mhz and would block the DC or 100Hz mains. Same idea used on many TV's with hot chassis on the 50's - late 80's.
Enclosed Mean Well PSUs have mains terminals like that. The annoying thing is that 99% of the time when you get a used one the terminal cover is missing and Mean Well doesn't seem to sell replacements.
5:48 maybe F and N are last words of OFF and ON as their starting are same so they choose the ending words
Deep, really deep. Love it.
Only when there is quality control. Which is far and few between.
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.
12:02 at night guess I'm staying up
They could put two capacitors in series to the antenna connections. Those would let RF through, but they would block mains frequency.
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)
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.
@@killcar5nbike2 This should be the kind of capacitors, which are used in switching power supplies between primary and secondary side.
@@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.
@@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.
Does live and neutral swapping really have any effect? I know neutral is referenced to ground - in theory - but in practice, current still has to get there from all electronics on the same circuit, so if you touch between earth and neutral, you're providing a second return path for everything you have plugged in, I guess up to the transformer feeding your power. A capacitor, limiting current, on the live side, does nothing to protect all that current flow on the neutral side, because you have that charge looking for a return path to earth from all other plugged in devices. If you short neutral and earth on a random wall socket, you'll trip the circuit breaker, showing that you're diverting the returning current (or, more accurately, a likely maximum of half the current, as it's a second, parallel connection).
Was waiting to find out about the RF circuitry - it was going to be the most interesting thing in a long time.What are those MOSFETs, for example?
Video coming soon with remote switch RF transmitter reverse engineered.
RIP Clive's green ink cartridge.
Bulk ink printer.
Functionality of this device is similar to "SOnOFF Wifi", which uses a proper flyback converter. SOnOff has better features, since it connects over wifi, the features supported are much more diverse and extensive. When I was looking into the SOnOff inside, I wondered why they did not use a capacitive drop power supply.
I guess, one reason is that 433MHz RF module may consume much lesser power as comapred to ESP32 modules used on SOnOff, but I could never verify that. Could you please do a comparison of both HW?
You know, what they could have done is put a y class capacitor in series with that antenna. A couple hundred picofarads should do. Low-frequency AC is mostly stopped by that but RF goes right through it. Additional cost is very low but it's much safer.
10:20 What is the very prominent helix of black wire stretching across the receiver circuit board?
Edit: a small short-range antenna.
Yeah, the model of the switches I have only has the small antenna on the receiver.
- Just under where it says „Made in China“ it's labelled wrong.
What a coincidence!
Made in your wooha by Dr. Wong.
So... maybe it wasn't actually Made in China, either? Could they have gotten that wong, too?
@@johnpossum556 No need for actual racism in comments :/
@@javaguru7141 Is it really, howso? I actually had a Dr named Dr. Wong. I just thought the name was funny. In actuality Dr Wong did me a lot of good. Myself and somebody else talked about him at a dinnerparty. He made the joke, I am only copying it.
He was Foley'ed by Dr Wong so he said it felt all wong. A Foley is a cather up your penis BTW. Also if you dislike making fun of Chinese products you might as well unsubscribe from this channel as it's a common thing. Same thing with AVE's channel and a couple of dozen other YT channels where this is commonplace. I just don't see it as racist, just funny.
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.
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
I'm wondering if the, "odd" design is due to our being originally designed for that much larger chip, then being, "redesigned", poorly, for the smaller chip?
Being a Ham radio guy, I wonder how many devices are floating around it there with this design flaw?
That being said, we operate at antenna voltages that present a shock hazard by themselves.
Thanks Big Clive. Very cool.
The 2 Zeners are not in parallel to share the load, one is just a hot standby if the other one blows.
Except that semiconductors fail by shorting. Besides, nothing else in this thing in redundant, why just the zeners? They clearly are sharing the load and two 12v zeners in series would be a better idea.
How did I not see this months ago?
This is one of my favorite kinds of videos you do.
Let me clarify some of those abbreviations
On the remote F/N is Functional not active / Now functionally active
On the output terminals A is Another neutral and N is Not neutral
Also ANT is not short for Antenna it is the Auxiliary Neutral Terminal
No sure how you could find that confusing.