Thermostat Remote Temperature Sensor Hack

hey guys Allen from hack gadgets here I've got a little device to my hand here we've all seen one of these you dial in the temperature you want and it turns you furnace on when it gets cold the issue with this thing is the location I want to mount this in isn't the optimal location that I want to monitor the temperature there is some ones that have wireless sensors that you can actually mount the sensor somewhere different than the location of the thermostat but I want to do it on the cheap this was already in the building however it was in one of the tenant suites and you know I don't want to have to bug attendants whenever have to adjust the temperature so I'm going to mount this in a mechanical room and I'm going to mount the temperature sensor that's in here as long as I can get it out of here and Maat and mount it remotely let's head over to the bench and see what we can do okay so here's the thermostat it's a something I acquired when I purchase the building so I haven't actually had a heating season in this building yet and we can see it's very basic however the system in there is really simple it has an on-and-off it's basically a radiator a hot-water radiator system so basically this turns on it fires up the natural gas heating system which heats up some water floods it over through all the rads with a big pump and that's how all the Suites get their heat so it's either on or off and either all the suites are getting heats or all the suites aren't I have a future plan I was hoping to get it done this year but you know not not quite in time but the future plan may be for next year is to use some of these sensors so these are temperature and humidity sensors not that humidity matters but it'd be interesting to monitor and what the future plan is is to mount these in every suite and maybe places like the mechanical room and laundry room things of that nature where you know you also don't want them to freeze and then what the future plan would be is to make sure that all of the Suites have a nice even temperature you know keeping sort of minimum temperatures in mind and also that you know the rooms like the laundry room stay above a certain temperature I don't care if the laundry room is at 15 degrees but I care if the laundry room is that you know seven degrees let's say so watch out maybe next year for this this plan here and the other nice thing would be you know using something like the ham radio APRs I believe it is something like that to actually transmit the data so that you can actually you know monitor it local remotely that would be you know ideal but anyway this is going to be a very very simple project hopefully as long as I can get the the temperature sensor out of here this thing is surface mounted it might be a no-go but I'm assuming it probably won't be okay so the not here I've already taken this off because I did have to take the screws out to get this off the wall so I have seen in here before so this is what we got on the inside quite a nice liquid crystal display and the interface on the outside is basically these two buttons and really it's it's either off or heats that's the only user control so when we push these two buttons here what that does is it actually allows us to okay it's off right now put it to heat that allows us to set the turn on temperature and 23 degrees that's actually the Celsius temperature in this room right now where this is being recorded and so we could say that you know let's say if the temperature goes below 22 to turn on and they'll just be really in here and I believe the connections were connected onto these ones here so they'll just be a dry contact relay that changes changes state to tell the system to turn on runs off of two doublea's in series so we just got a simple three volt system here and yeah we can see it's basically chip on board here so we won't be able to see any sort of microcontrollers because this will be obviously a custom die that's built directly onto the board I don't have the the manual for this but we can see there's obviously a program jumper that's been cut here for some modes and I guess so we don't have any cutouts for buttons here but obviously this is probably a multi-use board here for different versions there is some gold fingers here which are you know some of those membrane buttons would be on some models obviously okay so I'm not sure this is labeled s9 and that's interesting you put it or some document if there's some numbers on there maybe we can look up some documentation okay so we got a crystal up here this is a one that can handle different events at different times so obviously this is keeping track of time we have an LED for backlight here and we got a couple screw so let's undo these screws here and remove this board let's see what's behind here okay two screws are removed and this is just a snap together construction you can see we just have a little prying tab here and another one here at the bottom and it looks like all the connections are done through this flexible ribbon cable there so I've actually removed the batteries and you can see this thing is extremely low low energy here with the the LCD display it's it's basically running on batteries which is a good thing because then you can change the batteries and you're not going to lose your programming because the sync and obviously last by the way I'll just uh just hang it out on whatever charges lingering on the capacitors so I'm just going to pull this off here just a couple switches at the bottom so these switches are external there's another switch down here electric or gas so I'm just imagining that electric or gas is maybe just the the time delays between switching maybe something like that maybe when it's on one of the modes it it waits maybe after it hears a little battery symbol change the batteries it probably waits X amount of seconds before switching just so it doesn't you know chatter the relay back and forth and do some crazy stuff to the to the furnace controller so very simple construction on this bottom board we can see some some jumper links in here so this is obviously single single sided construction here so they've saved some money that way and very simple here is the actual relay that's obviously doing the the switching that'll be connected to this guy here directly not much to it and the back of this board yeah this is also single sided copper so it's all surface mount on this side and we have a few jumper links on the back here and interest in these little jumpers here that have been cuts the rack fee front soldered okay so I'm thinking the only item that that sort of sticks out is this little blue guy here let me see if I can make it focus on there so you know it could be anything in there it's not marked on either side and it looks like a capacitor you know but it is also proper size for a thermistor and so just to show you how confusing it can be you know so does that look similar to this this is a this is a point one micro farad capacitor you know sure does can you tell the difference other than a little bit of size not really but I'm thinking this is a device but what I'm going to do is I'm going to put an ice pack to side here and let's cool the sucker down and let's check it out okay so batteries are back in let me zoom in a little bit here and got a little ice pack here nice and cold out of the fridge all I'm going to do is I'm just going to rest this guy on here and let's see if we can make this this temperature sensor read colder and we should see this 23 drop okay so it took quite a while but we got it to cool down to 20 I think there's a very slow third progression so I'm assuming this is actually much colder than 20 degrees this probably took about a minutes to cool down to this so what I'm thinking is if there's drastic changes in temperature it probably doesn't update right away and I can imagine that's probably just to prevent things like if this was mounted near a door every time the door opened you know we get a blast of cold air and this one would immediately turn on so they're probably having some really big hysteresis in there so that it's a it takes a long time for the cold to actually affect it it's looking for more gradual changes which is you know generally what you get in the house anyway so we are going down and this is the only thing that I was touching with this cold here just right here so we have found the temperature sensor it is it is this device right here and thankfully it is surface mount and the other thing I'm just thinking let me just short this out if that is a temperature sensor shorting it out shouldn't cause any damage and we should see a drastic change in the or some some change here probably a like an invalid temperature or something will get there we go so it doesn't know what the temperature is it's just showing dashes now this is the set temperature so this one is nothing so if I release that it will probably go back after 30 seconds or so let's see what happens and now it's at room temperature or its it'll it'll start to be going up from room temperature so and there we go so we're at 16 so it's it's sort of reading the actual temperature now sure which is well below the actual room temperature in here which is around 23 24 so we're slowly warming back up to ambient and now we know where it is let's say desolder that guy okay pop the batteries out I'm going to be desoldering that with the hakko 808 it's a desoldering gun and if you've never used a die soldering gun they're awesome and this one I think is the the best one I've ever used it if you've never seen one of these types what it basically has is it's a trigger operated it's been plugged in for a few minutes so it's hot the tip heats up just like a soldering iron the back has a vacuum pump and basically you can see the the tip has a hole in it so what you do is you actually place the tip over top of your your through-hole device right on the lead you heat it you do a little swirl to get that lead molten there the solder around the lead molten and then you just give the trigger a pull and it'll suck all the molten solder right in so it's exit right through the tip into this chamber here in this chamber basically has a filter that catches all the solder and so the filters are replaceable the chamber is cleanable and so you're just good to go you can just do many of them so let's see how this thing works so we got to desolder those two leads right there I'll place it on a little pump and there we go so that one there is done let's do number two I'm going to place it on give it a swirl give it a pump there we go two for two so let's see how this thing works it was glued in also so I'm just gonna pry it off a little bit of glue on there there we go no sweat so if you're using a you know braided copper braid or one of the desoldering pumps the manual one when you do the plunger in yeah give it a press man that this thing is ten times better than that so here is the actual device so this is the one we're going to be mounting remotely it's just in a little holder and I'm going to be mounting it in this little project box here so this box will be mounted in a location this used to be and this has a little location for some wires to go in and ideally I wouldn't use this connection for the wires but I don't have the ones that would like to use I've run out so I'm just going to probably just hot glue this right to the back plate here and so I can have nice access to the screws the temperature sensor will be mounted well we soldered directly to these and there's a nice introduction for the wires to get to get terminated and as far as holes go what I would like to do I don't have time for this but what I would like to do is actually make a drill pattern so I could have a really nice sequence of holes on here I'll probably just well maybe just plunger just plunge a bunch of holes with a soldering iron or you know just maybe just take a drill to it and just just make a bunch of holes down the sides in the front just so that it can get some nice some nice airflow but still be protected so let's uh let's move on to that okay got a nice big fat tip on here nice and beefy we're just going to punch some holes here with the my crappiest tip I got and I got the iron cranked right up to four hundred and eighty degrees Celsius so it should take nothing to punch some holes in this and I'm just going to just make a nice little pattern here again it would be optimal to do it uh you know in a way that's oh and of course I there's a standoff in here and I think that's exactly what I hit let me move beside that there we go okay so there's a hole let me just make a bunch of holes and if you don't have yourself a set of these helping hands you should get them because there's no real better way of holding two parts together and then being able to get in there with with solder and your your soldering iron then using a set of helping hands to hold joints together while you solder them okay so this guy has been soldered on and all we have to do is stick it on to the back here I'm going to use the mini heat gun for this one and I want the temperature sensor you know somewhat centered so and obviously the wires are going to be coming in the top here so I'm just going to apply some hot glue right on the bottom here and I'm going to be quite generous with it if I thought about this before what I would have done also is a scratched up the surface a little bit so it had something to notch into but oh well I think this will adhere okay and I'm just going to remember that when it sin to want to make sure that I can still access the screws without them being filled with glue or blocked and it looks okay and I'm happy with that with that positioning okay so this side is done this is going to be closed up that's going to allow the air to get in there I'm going to have a wire coming out of here and this is going to be bolted to the wall I'll keep it in in this position here so that it dries and once that dries it'll be done okay and what I'm planning and doing is also mounting one of these same terminal blocks on this guy I'm going to be utilizing the same wire it is twisted it's not shielded in or anything but it is twisted wire that goes up to this location and it's not going to be very far from where this is going to be mounted probably about 15 feet so I'm not I'm not thinking I'll have any problems with a standard wire connecting these two devices I will test it on on this end here just to make sure that it is monitoring properly and as far as locating this goes you know I could just put you know pop it right here however you know that would look kind of ugly so I think what I'm going to do is just hot glue this in position probably something like that so I'll have or maybe over here so I'll have two wires coming out of here for the relay contact and then two wires coming out of here for the temperature sensor so it'll be you know a nice little unit here okay so terminal block is mounted wires are run under here ample amounts of hot glue here to hold things in place that should be fine the only thing I had to modify here as you can see where the wires came through there was a piece of plastic there just a little bit of melting was was just enough to allow those new wires to feed under and that's held in place underneath here with a few dots of hot glue also so it's a you know stays out of the way and I just snake some here and comes right over to this brand-new terminal block so it doesn't have to look pretty because nobody will ever see that just have to be functional okay so everything is wired up this is just one of these desktop units here so we've got about twenty four point two degrees Celsius in the room right now and we're showing 24 degrees on the system so we have the temperature sensor hooked up right here and it's just feeding around this is just a loop of wire it's around 35 feet so this is actually longer this is just station wire this is longer than what is actually going to be used in the field so I just wanted to make sure that you know this being plugged in remotely wasn't going to be an issue and clearly it's not so this is not going to be the sensor here or the wire connecting to the sensor this will be something a little different so when it's is all buttoned up here you'll just have a uniform cable coming in and that'll be the unit that's mounted in the suite this we mounted in the mechanical room and we're good to go for more information go to hacked gadgets comm

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