Non-Programmable Thermostat Modding

[bluto]

Hey everyone. I have not been posting much lately but tonight I did a little mod that I thought I would share.

I have two of these 1F78 non-programmable thermostats laying around since I replaced them in my house. I couldn't help but notice that the insides of these seem to indicate that they could possibly be made programmable somehow.

Tonight I started looking at this board for clues as to what it was missing. There were a few missing resistors, a missing LED & transistor under the display as well. I starting googling for the model number and found a picture (last attached picture) of the programmable model. So I studied it closely and determined the differences.

A short time later I un-soldered the zero ohm resistor from W1, soldered a jumper on W2, soldered a jumper across W903, and added a missing 1000 ohm resistor at R10 to connect rest of the button pads to the CPU. I put the batteries back in and my non-programmable thermostat is now programmable! Look at the last picture for programming instructions.

The only minor caveats are the lack of button holes on the cover and the hole for the display is cropping some of the LCD. But since I am just going to use this as a thermometer, it is nice to have a clock along with it.


It makes sense from a manufacturing standpoint to have one circuit board that can be both programmable and non-programmable with only some trivial modification. And then they slap on a different cover with some extra button holes. Lo and behold, they can now charge 50% more for the same basic unit.

[joshnz]

Re: Non-Programmable Thermostat Modding

Very nice

[3d0]

Re: Non-Programmable Thermostat Modding

Not much time spent from the manufacturer on making the board more harder to hack/mod.
Like everything these days, products are shipped in a rush to the markets.

Nicely done.

[desert-rat]

Re: Non-Programmable Thermostat Modding

Reminds me of some of the vhf/uhf scanners , you could cut one dioed and the scanner went form 200 ch to 400 ch. , or something like that. You could add a dioed and get the cel. freq.s 800mhz and 1300 mhz .

[stj]

Re: Non-Programmable Thermostat Modding

still the same, but now you just set the frequencys in software.

[momaka]

Re: Non-Programmable Thermostat Modding

Wow, very neat mod.
But why would the manufacturer cripple some of their thermostats like that? Wouldn't they make more money if they sold all of them as programmable? Sigh.

[desert-rat]

Re: Non-Programmable Thermostat Modding

On programable/non programable therms. People will get a programable thermostat and set it to one temp , thinking it will save them money . Some people dont undersand how to set them/dont read inst./ just dont take time to set one , ect.

[bluto]

Re: Non-Programmable Thermostat Modding

My house was a spec house so I suppose they need a bargain basement unit for contractors. And then there is the crowd with the blinking 12:00 on their VCR. The simpler the better for those situations.

[desert-rat]

Re: Non-Programmable Thermostat Modding

The programable therm.s do work , if they are set . Hear in the south west where it gets warm in the summer , if you have the therm. get warmer when no one is home , you can save some money . My point was , a lot of people get them , then dont set them rite .

[momaka]

Re: Non-Programmable Thermostat Modding

And then there is the crowd with the blinking 12:00 on their VCR. The simpler the better for those situations.

Yeah, I guess you are right. Explains why we have so many "dumbed down" products today too.

The programable therm.s do work , if they are set . Hear in the south west where it gets warm in the summer , if you have the therm. get warmer when no one is home , you can save some money . My point was , a lot of people get them , then dont set them rite .

Yeah, I myself have not actually seen anyone to "properly" program their thermostat either. Most just set them to one temperature and perma-hold it there until the season is over.

I do exactly what you mentioned above - when no one is home during the day, I let the house heat up (summer) or cool down (winter) a few degrees extra. It does indeed save quite a bit of energy. Another thing to keep in mind is that most people get colder as they become sleepy late at night, so that's another place where you can let the temperature drift up a few degrees (in the summer, that is).

[ratdude747]

Re: Non-Programmable Thermostat Modding

Wow, very neat mod.
But why would the manufacturer cripple some of their thermostats like that? Wouldn't they make more money if they sold all of them as programmable? Sigh.

Because of supply and demand. Increase the supply, and the price goes down on the nicer units. Same reason why intel and others would take good chips and make them celerons and the like...

[momaka]

Re: Non-Programmable Thermostat Modding

Same reason why intel and others would take good chips and make them celerons and the like...

Actually they do that to sell some of their "lower-quality" batches. The chips from these lower-quality batches are actually the same as the "good" chips, but due to manufacturing equipment tolerances and whatnot, some of them end up with bad cache or not able to run stable at full speed. These chips are then put aside, tested, and configured accordingly to run with a part of their cache disabled or at lower speed (or both) and sold as lower-tier chips. And this is not just common for CPUs and GPUs. Same can apply for rectifiers, transistors, etc.

[ratdude747]

Re: Non-Programmable Thermostat Modding

^some, but not ALL. some were legitimatly good chips that were intentionally downclocked... aka higher than expected yield.

[Hondaman]

Re: Non-Programmable Thermostat Modding

Nice work there.

In 1990 my family bought our first VCR. We could program it to record stuff when we weren't home, and watch it later!

Years later, I learned (I'm pretty sure of this) that if you had the IR remote control from a higher-end unit, you could type in the six-digit code found in TV Guide to record with the timer, instead of selecting start time, stop time, which channel, etc. I think it was a Toshiba VCR, but I don't really remember.

And most of us here know about the Canon CHDK firmware mod, since Canon used the same powerful chip on many of their lesser cameras, advanced functions could be "unlocked" in them. And one particular hardware revision of the D-Link DI-524 four-port router could, IIRC, be flashed to be a DI-624 (every capability of the 624).

Anyway, good job.