[HN Gopher] Automating My Air Conditioner
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Automating My Air Conditioner
Author : dguo
Score : 13 points
Date : 2021-10-09 20:56 UTC (2 hours ago)
(HTM) web link (www.dannyguo.com)
(TXT) w3m dump (www.dannyguo.com)
| snthd wrote:
| https://github.com/ct-Open-Source/tuya-convert is useful for re-
| flashing some widely available smartplugs without opening them
| up. Then you can use MQTT or HTTP.
|
| Unfortunately some newer plugs are incompatible with the hack
| (different chipset - https://github.com/ct-Open-Source/tuya-
| convert/issues/484 ).
| syntaxing wrote:
| Love the spirit of the idea and execution! I would guess the
| "temperature" knob ties to some sort of trigger relay downstream.
| You would probably be able to tie in a microcontroller of some
| sort to control it and maintain the process function like ramp up
| and cool down. But at the expense of requiring to open up that
| panel.
| sxp wrote:
| > If the temperature is above 75degF, the job turns the smart
| plug on. If the temperature is under 73degF, the job turns the
| smart plug off.
|
| Would turning on/off a high current A/C like this have any
| negative consequences? Some A/C units have a cooldown period
| after you turn them "off" via their button since they need to
| remove some condensation and perform other normal maintenance.
| Would that issue apply to cheep window A/Cs?
| brian-armstrong wrote:
| Yeah you will get condensation with these window units too. It
| might have a pan that has to be drained.
| dguo wrote:
| I believe most window units instruct you to set them at a
| slight angle so that condensation can drain out the back
| without manual intervention. At least mine do.
| ultrarunner wrote:
| Mentioning it just because I didn't see it addressed in the
| article: AC compressors & fans can be a significant current draw.
| If you want to replicate this project, it's probably worth
| checking the amperage ratings for whatever smart plug you use.
| Something intended to switch lights or a room fan may not be up
| for the task of repeatedly starting a compressor. Even if the AC
| unit only draws 15 amps (an so is fine to plug into a wall),
| inrush current could be an issue for an traic or SSR-based smart
| plug.
| sokoloff wrote:
| It sure looks like that thing has a thermostatic control. I've
| got similar window shaker units and they have a distinct click
| when the thermostat turns on or off and they do an ok job of
| controlling the temp in the bedrooms.
| dguo wrote:
| OP here. Wow, that's a good point. I don't know why I assumed
| that the first knob is just a static control for cooling
| output. Especially considered that it's labeled "Temperature."
|
| Looking at some customer reviews, I do see some complaints that
| it doesn't work very well on this model. But still, I should
| have read the manual. Thanks for correcting me!
| avh02 wrote:
| Definitely, that's what the numbers are for, but it takes a
| long time to figure out what maps to what temperature
| avh02 wrote:
| In university I had an air conditioner that would turn off when
| the power went out (regular occurrence, few minutes), so I'd wake
| up sweltering or otherwise needing to get up/interrupted in order
| to switch it back on (it had a cabled remote/controller)
|
| The automation was a clothes peg on the power button.
| glitchc wrote:
| A general note: Arbitrarily cutting and restoring power is a bad
| idea for a compressor. See the first answer at this link for a
| detailed explanation:
|
| https://diy.stackexchange.com/questions/145791/how-bad-is-it...
|
| In a nutshell, it takes time for the refrigerant pressure to
| equalize. An AC with a thermostat will have a timer to prevent an
| immediate restart after a stop.
|
| Another option is to introduce hysteresis into your control loop
| as the TFA author has done: Use a distinct power threshold from
| your off threshold. By setting the power on a couple of degrees
| higher than the cutoff, it will give the refrigerant pressure
| time to settle.
|
| To the author: I agree with the other posters. Looks the AC
| already has a thermostat, just no automatic fan control.
| simondotau wrote:
| I did something similar to the TFA but instead of switching the
| power on and off, I signal it with instructions to cool to the
| minimum and maximum temperature. (This was easy in my case
| because it has an infrared remote which I can emulate.) I'm
| assuming that any logic required to be mechanically sympathetic
| to the compressor is built into the AC's own controller.
| dguo wrote:
| Author here. Thanks for the heads up. From my experience, after
| it turns off, it tends to stay off for about 30-45 minutes. I
| hope that's long enough to avoid issues. The comment in the
| link mentioned delaying 3-5 minutes.
|
| And yep, It was my bad to misunderstand the first knob. I
| should have read the manual instead of assuming. I added a note
| to the post.
| [deleted]
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