SuperHouse #34: Science or sorcery? Sonoff T4EU1C no-neutral wifi touch switch

g'day it's John from super house futures here and today I have the brand new sauna off t4e you one see this little bad boy seems to defy the laws of physics I want to figure out how it works so we'll put it on the bench look at the text and the specs and see if we can work it out so let's go to the bench in three two one now before we look at how this little device works it's important to understand what problem it's trying to solve typical domestic wiring for light starts at the switchboard and then has an active and a neutral that typically go through the ceiling space wherever a light and a switch need to be installed the neutral is taken straight to one side of the light active comes down and goes to one side of the switch to switch to active then goes back up the wall and to the other side of the light from here you can see it's a very simple circuit power just flows down through the switch through the light and back to the switchboard then at each location where lights need to be installed this process is just repeated so the act of a neutral circuit just passes through the ceiling and meanders around between all the different lights let's simplify it though and just look at a single light to understand what's going on because the neutral just goes to one side of the light coming down the wall we only have two actives the active that comes down from the unsearched part of the circuit and the switched active that goes back out that's fine for a normal passive light switch but what if you want to replace your or passive switch with an active switch something like a sawn-off touch now an active switch has electronics in it which means that it needs power if you look at the back of this one off touch it has active in and active out just like a normal switch but it also has neutral in that's because it needs power to run it so in electronics these two connections active in a neutral in a vital for the switch to be able to function so to install this on off touch you have a problem if you only have the two actives coming down through the wall you don't have any way to power it what you really need is the neutral brought down as well there in modern wiring codes this is usually done in many countries it's legally required now to install a neutral to each light switch location because it's quite common to need to install devices they're not just a passive switch but if you have older wire this is probably what you have just an active coming down to a switch location and heading back up the wall now first glance it may look like this problem can't be solved we've got an active but no neutral so how are we going to get power it's like having a DC circuit where you have the positive and no negative but there is a solution let's look at a simple DC example first what I have here is a very simple circuit we've got a battery which is giving us about eight or nine volts out we've got positive coming through going to the switch from the other side of a switch it goes through to this led with a current limiting resistor and then back to the battery so it's a simple circuit with a switch in it and if we flick the switch you can see if that galley D turns on now when the switch is turned off no current is flowing in this circuit but this is the trick question in this circuit where do you think the biggest potential voltage is well let's have a look the interesting thing is that if will you chuck a multimeter across the back of the switch when everything is turned off there is no current flowing look at that we get voltage across the switch and the switch is turned off now the greatest potential voltage difference apart from at the power source is across the switch so if we pick up power across the switch terminals we can power something locally when the circuit is turned off and that switch is open now the thing is you've probably come across this and used it yourself and never even realized if you've used an illuminated door bell know one of the buttons that lights up and you press it the doorbell rings and as you press it the light goes off think about what's going on there what's happening is that the switch is an open circuit unless you press it there is a light globe wired across the back of the switch so when the switch is open power goes through the globe and illuminates it when you press the button the globe goes out because the switch is short-circuiting across it and all the power is going through the switch instead of through the globe so you might then be asking well then why isn't the door bell going off continuously if power can flow through the globe that's because the globe only allows a very small amount of current to pass another factor that many people forget is a traditional incandescent light globe is basically just a super-sized resistor with a really high power rating we grab a multimeter and see what the resistance is across this particular globe what have we got there's so many six ohms so this is basically a 50 watt 7609 resistor on our circuit down here taking the switch out it's a very simple circuit just with the LED in it what we can do is we can just put this light globe in series pass power through it and the LED lights up the globe doesn't actually glow because it's not getting enough power but it's just acting as a resistor in series with the circuit we can pull a small amount of power through that light globe and it won't turn on so now I've upped the ante with a main circuit with an extra little power supply hanging off here what you can see is the active coming in to one side of the switch going out the other side of the switch to the light globe and their neutral comes back around and it just loops past it's got nothing to do with the switch circuitry at all that would just be normal except that I've got this little switch mode power supply hanging off it this is a power supply that takes mains input and it gives five volts output I just got an LED wide across the output so we can see when it's running and that is wired across the switch so now I've got to plug it in I am make sure everything is turned off most of the time but what you can see now is the switch is off the light is off but the LED is on that's because the power supply is taking power through the globe and across the switch terminals now it's kind of difficult to see because the globe lights it up I'll put this here for shadow purposes and if I turn on the switch which turns on the light globe you'll see that the LED fades out that's as the output capacitors on this at all voltage regulator inside here dissipate and if I turn the light off the power supply comes back on again turn the light on and after a couple of seconds the power supply fades out but what you can see here is that we're getting power to run something at the switch location while the light is off and we don't have a neutral to the switch location here but the neutral wire comes through but it's not having anything to do with the direct switch it could be any distance away in the house so what we have here is actually getting pretty close to a system that would allow us to run a smart light switch with electronics running locally the problem of course is what you do when the load is turned on how do you get power to run your local electronics as you've seen in this example when I turn the output on we lose power because we have effectively have a short circuit through the switch and there's no voltage potential across it so we can't tap it off well we'll get back to that later it's actually easier than it sounds but for now let's get into the actual T for EU 1c and see what it's doing I've wired up this on/off and paired it with my phone just an usual way using the ear where link software that's not particularly interesting sorry that's not what we're here to look at today the interesting thing is the wiring you can see here we've got active coming in going to the switch active coming back out again going to the light and neutral just bypasses the switch entirely in a normal situation all of this cabling would be up inside the ceiling space these two Brown wires would come down through the wall and this switch would be located somewhere that it's handy to get to but both of these wires are just the active going through to the load and as expected we can use the ear wielding firmware to turn it on and off and I can use the touch to turn on and off stay synchronized does all the normal a we linked functions it also comes with this little device which they call an anti flicker device we'll look at that in just a second I haven't bothered connecting it yet that's meant to go across the load in some situations to prevent flickering and it also helps to pass power through with some types of load as well we'll get to that in just a moment because what we're really interested in is looking inside this device see what magic it's got hiding in there yeah just like other sawn-off touch models if we can pull it apart by prising these little tabs open front cover comes off and that is the main logic board let's prise this out and see what's behind it well just like with the other touch models it's a two-part system so we have the high voltage part back here and then this is logic so we can see on here there's an inductor a diode a couple of other things that's probably the power supply for the 3.3 volt logic and then there's a connector here which goes through to the back board and this is where the interesting stuff happens as far as no neutral is concerned this front part is just a pretty standard control system it's got the processor the touch sensor and voltage regulator let's take this apart and see what is on the high voltage board down learn more about this we're going to chuck it under the microscope let's take a closer look low voltage logic board is very nicely laid out it's pretty easy to follow but you can see the esp8266 okay tree just down the bottom is the programming header in the format that we are so familiar with up here is the LED that closed through the front panel and illuminates the little Wi-Fi logo that's not actually the LED that illuminates the main part of the switch that's inside the contact area just below it right here this is the contact sensor which sits directly behind the acrylic faceplate on the other side of the board directly behind it is the touch sensor I see now this is a whole tech touch sensor and it's actually pretty clever it's a complete MCU with only 6:00 p.m. and it's designed to have two touch sensor inputs you can see the via and the track that come through the middle of the board leads through resistor r12 and then into one of the touch inputs on the IC this is needed because the ESP 85 doesn't have any touch sensing inputs this IC takes care of it and then just delivers a logic output that shows when someone is touching the front of the switch now one of the first things I always look for on a sawn-off is where GPIO 0 is connected if you trace the pin off the processor down here you can see it comes up and then diagonally up and left and ends in a via that fire goes through the PCB comes out on the other side right on the end of this resistor R 10 that resistor is then connected to the output from the touch sensor IC so what's happening is that the touch sensor is driving GPIO 0 low when you touch the front panel that's just like pressing the button on a normal sign off so in this case it works just like you would expect any normal sana except that it's a touch sensitive surface instead of a button one of the interesting implications of this is that the point here where the yellow arrow is pointing is the only place on the entire PCB other than on the chip itself that you can pick up GPIO 0 that means if you want to put it into boot loading mode you need to connect something to this end of the resistor which is really quite tiny another thing that's worth looking at is this eight-way header this is what links the low voltage logic board to the higher voltage mains board that sits behind it this header has three connections for ground and three connections for 12 volts in this is 12 volts that comes from the high power board and it comes into this one that then flows into that little voltage regulator just to the left of the connector and it produces 3.3 volts to run the logic and also provides that 3.3 volts back out through the connector to the board below there's also the relay control output this is how the s pH 2 8 v drives the relay on the output so the logic board in the sawn-off touch switch is actually really nicely designed it's very elegant and it's pretty much all so I've contained you could power this up from some power supply and have your so a nice little self-contained touch switch that you could run tez motor or whatever you like on it but what we really want to see is what magic is going on in this mains board the top side of the mains board includes the connected down in the corner which links through to the logic board that sits on top of it you can also see the live in and live out connections here let's start by tracing the tracks on the bottom side of the PCB you can see that a trace comes down from the live in and it goes into that tio 252 package looks like a MOSFET or a triac the part number on it is an FTD zero for n 0 for nd and the only reference I could find to that was a Chinese website called RF China comm and the page doesn't even exist anymore it's just a phantom sitting there in the search results however given the context I'm pretty sure that this is a triac it doesn't make sense for it to it be anything else from the other side of the track you can see that it goes across to the relay and from the other relay terminal does a bit of a dogleg around and ends up back at the life out connection though in both the relay end of the track had been activated you can see that this makes a direct circuit between live in and live out so in the track and the relay are activated whatever load is connected is going to be powered up but what's going on here there are a couple of parts that look like they're directly across the terminals the black part on the left is a fuse and the blue thing is a moth now a fuse is generally a closed circuit unless it blows a moth is normally pretty much an open circuit and it acts to suppress transient noise so ignoring the track and the relay part of the circuit for now what we have is a connection between live in and live out that is broken by the moth now remember what we learned when we're looking at that light globe earlier effectively we have mains potential across the moth and looking at the other side of the PCB where those morph pins come through you can see that we have mains potential between these two points and following the traces down from there they go into a bridge rectifier and then the output of the bridge rectifier positive or negative comes down to this weird-looking little seven pin chip it's like a top eight but one of the pins is missing that chip is an LP 3-6 69 and I went digging and found it's - a it's a really clever little power supply management chip that uses feedback from the input in order to regulate the output now the only datasheet I could find for it is in Chinese so I checked it in Google Translate and the summary says that it's a dual winding control chip for high performance isolated adapters and charges eliminating the need for exhilarating z' of a transformer and optimizing system cost so basically it's a smart power supply now looking at the Chinese datasheet for this we can see a couple of examples circuits that look very much like what we've got on this PCB you can see here the bridge rectifier and connect through to the chip the LP 366 nine you can also see that there is a triple coil transformer and as we'll see in a moment what we have on the board is a triple coil transformer and that then gives us the output voltage here which can be used by other parts of the circuit the reference schematic showed a three coil transformer and if we look at this one on the board and check the pins that come through the other side you can see that yes there are six pins which means this is a three coil transformer so what we've done so far on this mains PCB is how it controls the output using the relay and the track and a fairly nice power supply and it's pretty easy to understand when the output is turned off the relay is open how the power supply gets it source of power it's just tapping off the voltage between those two terminals but what happens when the relay is closed and the triac is activated which effectively shorts between the two live terminals and turns on the load how does this get power well hold on things are about to get funky the trickery starts right here this is the gate for the triac so this controls when it's turned on and off if we follow that trace across you can see it goes to a via net via pops up on the other side of the PCB just over here it then follows down the trace and ends on our 14 and on the other side of our 14 is a transistor so that transistor is obviously used to turn the triac on and off that means this particular sawn-off has independent control of the relay and of the triac which are connected in series I want to connect in a sauce cope up to and see what's going on so to do that I'm going to solder a couple of wires on here just need some way to make a good connection I found our 14 just up here so solder a little jumper wire on to that and we've already found down here on the connector that these bottom three are ground which comes around to this pin so I'm just going to solder on to that and that'll give us the connections that we need to be able to connect the oscilloscope so what I'm going to do now is wire this back together and connect it up to mains now the mains here is disconnected it's not live I'm not still enough to try connecting it while it is so I'll just screw these in then I'm going to reconnect the logic board to the mains board this will return it to its normal operational state and it still has its original firmware on it so if I powered that up it should operate as normal but now we have connections for ground and the gate on the on that triac so let's make some connections this one is the ground connection and this one is the gate connect up power make sure my hands are well clear no smoke comes out that's always a good sign so now what we can see is that in its default state the voltage on that track is zero track is turned off the relay is turned off now I'm going to turn the output on using the app and look what's happened we've now got the load activated and the track is being tripped at 50 Hertz so what does that mean well the relay is turned on at the moment it's just hard on it's not chattering the triac as we can see from the here is actually flipping on and off 50 times a second so what that means is that the light is continuously lit but the power to it is being interrupted very briefly and that generates potential across those connections so even while this is running power to the load it is very rapidly turning the output off using that to generate power through the power supply which is being stored in this big output capacitor and then turning that triac back on so that the load can get its power it's then coasting through that period turning the triac off charging up its output capacitor and it just keeps doing that 50 times a second so the result is that it's faking it it looks like we're getting continuous power out but it's actually turning it off very very briefly just enough to get the power that it needs to run its own electronics and now if I turn the output back off it doesn't need to keep flipping the triac so the output is open circuit which means that it's got full potential across those terminals - whatever drop there is in the load and it just runs the power supply as normal so you can see that we have a power supply that runs in two different modes when the output is turned off it's got the potential across those terminals and it can just run as you would expect a power supply to run and when the output is turned on which means that the relay is closed the triac is on it's short circuited it's basically coasting on the power that it's got built up in that output capacitor and then periodically turning off the output to generate the potential that it needs to get some power build the charge up in that capacitor again and keep right on going finally we come to the mysterious anti flicker device I haven't been using this so far in the demonstrations that I've shown you so what is it how does it work do you even need it let's start by opening it up and find out what's inside what we have are just a couple of metal film capacitors these are 450 volt rated so mains rated caps you can see there's a resistor in the middle you is what is it brown red yellow so that's a 120 kilo ohm resister it's pretty big looks like 2 watts or so and there's a thermistor on it these are pretty commonly used for inrush protection in AC circuits so as we can see from the back of the board these two capacitors and the resistor are wired in parallel and then the thermistor is in series with it so what we've got basically is a couple of capacitors across the back of the load so if this is connected across the back of the light what it will provide is a pathway for AC to pass around the load itself now in an AC circuit a capacitor effectively allows some current to pass you can think of it as being equivalent to a resistor in a DC circuit so what we can do is calculate how much power this will allow to pass across it so what we need to do first is figure out what the capacitive reactance is now these two capacitors are two micro farad's each they're in parallel that means it's effectively a 4 micro farad capacitor so we can figure out a capacitive reactance XC is equal to 1 over 2 times pi times the frequency times C now we know PI 3.14159 we know frequency is 50 Hertz and we know it's 4 micro farad's so let's do some calculations so we'll say 2 times pi times 50 Hertz times 3 4 5 so 4 micro farad's and then 1 over x equals so 795 so that's equal to 795 ohms effectively so putting this in a AC circuit at 50 Hertz is like having an 800 ohm resistor in series with it and from that we can calculate how much current is going to pass so we know from you know just like normal DC Ohm's law current is volts over positive reactants so that is going to be equal to 240 volts and we just figured out the capacitive reactance is 795 ohms so what does that give us 240 divided by seven ninety five equals zero point three so what we've got is zero point three amps that can pass through this at 50 Hertz so by putting this across the back of the load it effectively means that 300 milliamps can pass directly around it not going through the load itself and you might be wondering why that matters everything was working fine well remember that with the example I've just been using this old-style incandescent globe which is effectively a big resistor as we've already seen power can go through it and you can pull a bit of power through it without lighting up it's not a problem but what if you have a different type of lamp something like one of these CFLs let's see what happens you know here we've got the non neutral sawn-off touch connected up through the regular lamp and if I touch this it works as normal now if I take this lamp off what's gonna happen is this is going to lose power because there is no path through here anymore and we'll plug in the CFL instead and see what happens don't know whether you can see that well on camera if that is flickering so if you're in a darkened room this lamp would be continuously flickering even when it's turned off but sometimes you get something even worse happening watch what happens here turn the sign off on and it turns itself off turn it on I can't it's because it's reset and it's resetting again what's happening is that there is not enough power getting through the load to actually allow this one off to run its own electronics and if there's not enough current flowing through the load like if you've got a very efficient load it won't be able to power up by putting this across the connection it'll allow some power to flow and this can keep running and it won't be passing that power through the load making it flicker and also potentially making the sign off itself starve it power and turn off now I've connected that anti flicker unit across the globe and we can see that there is no more flicker there is power on this now that sawn-off is up and running and if I turn it on the lamp operates as normal and everything is fine no flicker of course there is now a small amount of power which is going to be passing through the anti flicker unit in order to keep this alive and that is one of the minor downsides of having to do this what this is doing while the light is turned on is wasting power because up to 300 milliamps is going to be bypassing the light and flowing through the no flicker device it's only a small amount of power but it's using a little bit more than it would otherwise so what I suggest is don't just put it on unless you know you need it if you are using incandescent type globes don't put on the anti flicker device and just test it out first if it turns out you need it then put it on so if the capacitors are what allow power to pass through this why does it have a resistor on there that doesn't seem to make a whole lot of sense in an AC circuit like this well that's actually an indication that I teed have done a really good job of thinking about ways that this system can fail the thermistor for inrush protection is a good little safety feature but that resistor is there to protect you or your electrician imagine that these capacitors were charged up to mains voltage and this was disconnected they could hold that charge for a long time you could give yourself a really nasty shock across it so what this resistor does is discharge the capacitors over time let's do a quick calculation and see how that would work now discharge period on a capacitor is equal to resistance times the capacitor value and so we know the resistance is 120 thousand ohms 120 K we got that from the color code and we know that the capacitance in farad's is zero point zero zero zero zero zero for ferrets so let's work that out we could say it is 120 thousand times point one two three four five four equals zero point four eight so that time period equals zero point four eight seconds now that is to discharge to 63% of of the energy content the discharge curve on a capacitor basically follows an asymptotic fall toward zero and after about five time periods it'll effectively be zero or close to it and point four eight of a second per time period it means it two and a half seconds after you remove this connection these capacitors will be well enough discharged that you won't get any shock from them so good thinking i teed nice little safety feature to include in there what a lot of people do is just put a capacitor across the load they don't think about those extra safety issues so that's really nice to see and of course the big question is can we run as motor firmware on this well the good news is that if you get to has motor on to it it works just like a sawn-off basic the GPIO is are all set up in the same way so you just hit the the basic profile and it works there touch switch works because it's on GPI is zero same as the switch on the basic the bad news is that this is probably the hardest sawn-off that I have ever had to flash getting that image on there was really really painful and I would go so far as to say that if you don't have good magnification and you're not comfortable with reworking surface mount parts this may not be the project for you part of the reason for that is if you open up this on/off we've seen the deprogramming header on here but as i've explained already the only location that GPIO zero can be picked up is from the edge of a little Oh two oh one resistor which is mounted in here and you can see on this one that I've actually butchered this one already I've got a little blue hook up Y here and I've had to put a new surface mount resistor on so if you're not comfortable with making connections onto these tiny little points then you're probably not going to be able to achieve this now I don't think that I teeter necessarily being deliberately difficult with this on previous on offs it's been possible to pick up GPIO zero and other important connections in reasonably easy to get places on this particular board it's really really difficult well there's an interesting observation to make out at that because GPIO 0 is required to put the ESP 8 2014 2 is reflash chips are in something like a zero insertion force holder or even have them pre flashed by the manufacturer so that when they are flowed onto the PCB the firmware is already on them ready to go and the only explanation I can have for there being no access to the strapping pins on this board is if the MCS are being pre-programmed if you decide to give this a go I highly recommend it he set up a serial terminal that is capable of doing an unusual board rate in 874 thousand eight hundred and eighty bits per second that's because the ESP H wait five outputs it's booting debug information at that board rate but most serial terminal can't do it if you use cool term which is the one that I like that runs on Linux Mac and Windows you can easily add that as a board rate in the same directory as the cool term binary all you have to do is make a txt file and put seven four eight eight zero in that text file and call it board rate dot any next time cool term starts up it'll look in its own directory for that file and it adds any board rates in it to the list so now you can select seventy four thousand eight hundred and eighty bits a second and you'll be able to see the debug information coming back from the processor the programming header already gives us some of the connections we need but we also need to pick up Apio zero and reset now you might be wondering why I say reset because normally what you do is put GPIO zero low and then connect the programmer which powers up the board and if at power up the the processor sees GPIO zero is low it goes into bootloader mode but in my experimentation with this I've had some trouble getting it into bootloader mode and I often have to try multiple times so what I found is the most reliable is to hook up a wire to the reset line and put a button on it that way I can start ESP tool running attempting to connect to the board and then press the reset button and know that the board is going to be in bootloader mode so to make that easier what I've done is wired up a couple of buttons so I'm going to use one for a GPIO zero and the other one for reset the blue lawyer here which just just comes off the middle can go to ground I'll take your red white or reset yellow wire to GPIO zero so when it's all connected up I can just hold down one button press reset let go let go of the other and we should be in bootloader mode but getting the connections onto the board is the tricky bit as you can see here under the microscope I've already butchered this part of the board this is the touch I see and so I had to run a jumper wire around to pick up the other side of the PCB and I've installed a new resistor here which is in series with GPIO 0 and the touch sensor I see so what I'm going to do in order to connect onto GPIO 0 it's great back a little bit of the solder mask that is on this track now this track on the microscope like this it looks like a pretty decent size but it's 3/10 of a millimeter wide so there's really not a whole lot of space here to be working with so I'm just going to turn that track looking at this with the naked eye it is just a tiny little thing like a human hair and I also need to pick up reset and ground so let me get a bit of focus here reset is this end of this resistor and ground is available conveniently in many places I think I'll probably just take it off the end of this capacitor grab some tweezers to control the wire bring the blue wire in here just tack it on to the end of that capacitor then I'll bring red in just over the top and tack it onto the end of this little resistor and then just further across on the PCB here I'm going to bring across the yellow wire so that we can assert GPIO 0 now we have connections to the vital parts of the anatomy of this processor so we can connect it up to the serial programming adapter now you can use your own cable as I've shown you how to make in the past or use one of these little adapters like I've got just make sure that you use a 3.3 volt USB to serial adapter because these boards can't take five volts so what I can do now is connect this through here it's powered up the board and it's ready to to put it people into flash mode but because I've got these buttons here now to put it into bootloader mode all I have to do is hold down the button connected to GPIO 0 press the reset button let go of it let go of GPIO 0 and now we can run ESP tool and flash this board and now this is where things get weird and I've tripped up quite a few people that have tried to get test motor running on this particular model of sawn-off it can look like the flash has worked ESP tool will report that it's writing the flash gets 100% says that it's resetting the board and then when you power cycle it or reset it it doesn't come up there's no Wi-Fi it looks like it's booting but it doesn't work and what I've discovered by watching the debug messages from the the bootloader is that it seems to have some kind of a checksum problem and the way around that that I found is to assert reset and GPIO 0 after starting a SP tool so what we're going to do is use ESP tool in the usual way I'm going to load this on off binary I've started it it's failing to connect at the moment because it's not properly in bootloader mode so now I'm going to hold down GPIO 0 press reset let go and look now it started the upload and if you begin the upload using that particular process using the two buttons that I've got wired to it it seems to work but particularly if you just have GPIO 0 connected without the reset connection and you assert GPIO 0 apply power to the board and then try flashing that way it can appear to work but then fail there we go got 100% upload and this should now be functional now I'm pretty confident this has worked so first thing I'm going to do is remove the these buttons I just got to drop these little wires off where I found attach them and then I can put it all back in its case so this is the main part of the board here blue tack holding it on and so I just got to clip it back into place and also it's worth mentioning that while you're doing this reflashing it's easiest just to have the logic board separated definitely don't have any mains connected but if you don't even have the back board connected it's even easier so now I can just click all this back together and connect up my mains now I've already been through the process of setting this up all the configuration is in place it's got MQTT configured in taz motor so it's logged into my MQTT broker and it's all ready to go so it works as normal just like a sawn-off basic and on my phone I can use that to control it as well so this is using no dread which is just publishing to MQTT and you can see that it's all working fine with tez motor on it the LED is illuminating correctly to show when it's on button works the network works it's on Wi-Fi everything is functional so you see you can get tez motor onto these as long as you follow that sequence if you just hold GPIO 0 low when you apply a power through the programmer it's not really going to go into bootloader mode properly now I don't know what the reason is there's something weird about these particular boards and it's not just me that's had problem with it many other people have as well but if you connect to the reset connection and also to GPIO 0 then you can do this now finding those on the board is little tricky so on the Super House website I'm going to have nice pictures that show you exactly where all those connections are so that you can follow along yourself and also make sure you jump on the super house disk or there are more than 500 people on it now it's a great place to talk about home automation topics DIY projects so if you have a domestic wiring situation where you don't have neutral available your light switches and you want to retrofit the 240 u 1c does seem like a pretty good option in terms of its engineering quality it's certainly as good as I could possibly expect I'd have done a very good job of making sure that this is as safe as they can make it and it seems to work very nicely it would be nice if they had brought out GPIO 0 and reset onto nice pads where we could access them easily but if you can use a microscope or magnification and get connections onto those then you can get tez motor onto this and have total control of your no neutral sawn-off touch t4 EU 1c so thanks for watching now go and build something cool [Music] well that resistor is their protector yeah

Channel: SuperHouseTV

Views: 79,541

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Id: VNYcD7MEp4A

Length: 42min 16sec (2536 seconds)

Published: Sun Sep 29 2019