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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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:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
You videos are amazing
Cover the exposed antenna with a thick plastic housing. Then it would pass. So near to a great design. Zapp! Brilliant video. Thanks.
"F" is for "ofF" and "N" is for "Not off"
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.
Where do you get the plug socket from that you use that has the multi display on it. The one you use in your videos. Thanks for your help.
off and on switches were N for oN and F for ofF
I'm amazed at the number of gadgets bought on eBay that have potentially lethal faults or designs – in this case a metal antenna housing that's connected by a diode to the mains input. I have two question:
1. Whatever happened to Trading Standards in the UK?
2. Are there similar dodgy products for sale on Amazon?
If you look at the back of the SMA antenna socket you'll see a coiled wire going to the receiver module, that black coiled wire is the original antenna for the receiver module, it looks like it was not designed to have another antenna tagged onto the end of the original antenna wire. Someone further down the list here very rightly suggested that the external antenna may make the sensitivity of the receiver worse, and I agree when you see the original black coiled wire antenna is still attached.
Disconnect the black wire from the connection to the SMA external antenna and let the black coiled wire float within the plastic case, and it will work just as well, if not considerably better.
That way, no external live metal work and a receiver with the correct antenna.
Now how do you address the wrongly marked Live and Neutral output connections………. CLIVE…….. Where's the Sharpy…………..!
K Watt.
That is the most hung SMD push button I've ever seen.
Is there one available in the market that does what this does and also safe?
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.
Oh no. I have one of these right now connected to the 240v water pump supplying my house so I could control the pump based off the pressure seen at the house instead of the pressure seen down at the pump house.
I regularly got shocks off my Samsung S7 metal chassis phone while using the standard non earthed samsung fast charger, pretty worrying they don't earth stuff like that!
ofF and oN. Makes perfect sense. Would you call those tailiviations?
Maybe 'F' and 'N' because they are the last letters of "off" and "on"?
Scary stuff.
F = Off, N = On. Ingenious!
I love these videos.