Controlling A/C remotely (what to use?)

[Dannyx]

Good day folks. Summer being in full swing, I thought I'd automate my home a bit and come up with a way of putting the air con on even before I arrive home. It does have a time delay feature that goes up to 2h, so you can set it to turn on/off after 2h, but that's the maximum range you get, so if I'm gone for more than 2h, it's a waste of energy if comes on and cools nothing, plus once it IS on, you have no way of telling it to turn off again so it just keeps on going.
Of course there are probably many projects out there describing what I want, but trying to keep the component count and budget to a minimum, I'm not sure what I should use exactly. I have an Arduino Mega on hand, but from what I understand that's not enough. Not counting its obvious lack of any network features without a shield, I learned it's not fast enough to handle both the remote codes and the network environment at the same time. Most home automation projects seem to revolve around the Raspberry pi of some sort and I was thinking of getting one of those and giving it a crack, despite not having worked with one ever before.

I DID see them in action and had a brief look into it when my workmate automated the lights in his house and even designed some sort of remote desktop client/server thingy with one (to this day I'm not sure what all that mess was trying to achieve that a PC couldn't, but anyway). He tried "luring" me into all this home-automation business, but I didn't really play along since I regard it as a waste of time and especially money, especially for small apartments (why would you need to turn a light on if you're not at home?), but the A/C is one thing you WOULD want to control remotely and I'd like such feature, so perhaps it will be a good learning experience after all. What do you guys think ? Any thoughts or good resources on this ? What should I look into ? Hell, maybe someone's already done this and can provide some direct feedback. Cheers and thanks.

[stj]

Re: Controlling A/C remotely (what to use?)

connect a microcontroller between your router and a solid-state relay.
then control shit from a browser!!
http://tuxgraphics.org/electronics/

[Dannyx]

Re: Controlling A/C remotely (what to use?)

Hmmm...not quite. Plugging the thing in is not enough: it's got a soft-on feature so it wouldn't start anyhow and to be more specific, I want to emulate the functions on the remote...this chap got the right idea...

[stj]

Re: Controlling A/C remotely (what to use?)

well the schematics and code are there for 2 way stuff.
you could control stuff and see the temps or whatever.

[desert-rat]

Re: Controlling A/C remotely (what to use?)

I don't know if this will do what you want but you can get programmable thermostats.

[eccerr0r]

Re: Controlling A/C remotely (what to use?)

well, I think the OP is using a window unit of sorts and not a central HVAC system, so most likely some hacking or complete system replacement is needed -- sounds like the former is most likely.

If the remote emulation doesn't work, it's time to take apart the front panel and add electronics to "press" the button(s)...

[Dannyx]

Re: Controlling A/C remotely (what to use?)

well, I think the OP is using a window unit of sorts and not a central HVAC system

Partly correct: mobile air con unit, the type you wheel around. It's a Vortex in case it matters. I added some pics of both the entire thing plus the remote, in case someone goes "oh, I know this remote, it's the same thing as X", since I'm sure it's generic and used by many different brands....smiley face on there too

If the remote emulation doesn't work, it's time to take apart the front panel and add electronics to "press" the button(s)...

Pretty tough getting in there, plus not all functions on the remote have correspondents on the unit itself. IR is the way to go in this case.
I looked into it some more and apparently A/C remotes send all of the parameters shown on the remote screen at the same time: temperature, fan speed, swing on/off, so I'd have to capture all the different possible combinations, starting from the lowest temperature and working my way up to the highest, so 16c, low, swing on / 16c, med, swing on / 16c, high, swing on, etc. I was then thinking of a user interface where you have like a drop-down menu for the temperatures and radio buttons to select parameters like fan speed and swing (these 3 are the only ones I require really) and then a "send" button to send that combination via the raspberry or whatever micro I'll be using.....sure, sounds easy, but for someone who's never designed something like this in practice, it's a challenge.
Temperature ranges from 16c to 32c, so 16 combinations right there
Speed ranges from low to med to high, so 3 more there
Swing is on/off, so an extra 2....add every single possible combination of these up and we get, by my calculations, so correct me if I'm wrong, 102 possible combinations...I compiled a chart of how it should look...I'm sure you get the idea.

[eccerr0r]

Re: Controlling A/C remotely (what to use?)

Yeah, people tend to just record the remote and playback to remote control it. (the RF ones are another story!) Seems that the remote has some peculiarities in it, most remotes are dumb and just send codes as they're pressed but this one seems to have some sort of local state... Looks like a bit more complicated rev engineering job there!

[Dannyx]

Re: Controlling A/C remotely (what to use?)

One thing I noted is that if the remote is already "on" (but the unit is off, if I press the power button while in another room or blocking the LED), if I THEN adjust any parameter whilst now pointing it at the unit, it will come on with those parameters despite not having actually pressed the "ON" button.

For example, if the remote shows 16, low, swing on and I press the "up" button to go up one step to 17C, the A/C will turn on at 17c, low fan speed, swing on, as the "on" command is carried as well, so all those values would also have the "power on" command associated with them in my chart, since OFF would be a separate one entirely with no other value. Just thought I point this out as an extra detail...the only way to find out is to actually go for it and see if it works...I'll probably borrow my mate's pi to try it...

[brethin]

Re: Controlling A/C remotely (what to use?)

I have central air but got a window unit for my computer room, it came with wifi, LG unit,. Works great.

[petehall347]

Re: Controlling A/C remotely (what to use?)

build a phone app or just buy one

[redwire]

Re: Controlling A/C remotely (what to use?)

I'd use an ESP8266 for it, it's got WiFi and there are IR remote TX/RX libraries for it.

You could program it to show a webpage, which them sends IR LED blips to the A/C unit.

[Dannyx]

Re: Controlling A/C remotely (what to use?)

That's basically what I want, but I thought about the Pi because it seems like it's got more potential in the long run if I ever get bored and want to move on to another project.
In favour of the ESP, I reckon it's cheaper and can be "embedded" in the final project, instead of having to sacrifice the Pi and dedicate it to JUST sitting in front of the A/C.

[Curious.George]

Re: Controlling A/C remotely (what to use?)

I don't know if this will do what you want but you can get programmable thermostats.

Or, a $10 appliance timer that applies power to a small resistive HEATING load placed near the sensing element (of a wall mounted thermostat, window unit, shop unit, etc. -- a "universal" solution )

[eccerr0r]

Re: Controlling A/C remotely (what to use?)

Problem being, that likely the desire is to keep the AC turned off when there are no occupants. When an AC is being used, this is most likely be used during the summer, and to keep the AC off, that sensing element needs to be kept cool.

Now to keep that sensor cool we'd need some really funky device. A peltier? An empty NiCd battery being charged? Negative resistance heater? Oh boy... pretty messed up...

It does give another possibility however, perhaps another way is to use a relay to switch in the sensor or some other dummy circuit that keeps the AC off. Either way, looks like some surgery is needed, and hopefully we know how to fake that sensor. Needing to fake an i2c sensor may complicate things...

[Dannyx]

Re: Controlling A/C remotely (what to use?)

Nope - all of that is too complicated. The A/C is not permanently installed as you can see and it's not a HVAC system employing a thermostat, so the only method here is the remote. I found a project (can't remember if I linked to it here) using an ESP that does just this...the only problem is adapting it to fit my unit. That one was for a Daikin I reckon...

[Andyy]

Re: Controlling A/C remotely (what to use?)

Most home automation projects seem to revolve around the Raspberry pi of some sort and I was thinking of getting one of those and giving it a crack, despite not having worked with one ever before.

Even without a RPi, you should be able to use your PC to record and playback remote codes. Once you've verified this works with your A/C, you can copy the remote codes into the RPi's software.

[Dannyx]

Re: Controlling A/C remotely (what to use?)

Even without a RPi, you should be able to use your PC to record and playback remote codes.

How would one go about doing that ?

[stj]

Re: Controlling A/C remotely (what to use?)

LIRC project.

[Dannyx]

Re: Controlling A/C remotely (what to use?)

Ah yes I remember that...something to do with Linux I reckon...