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Bogartz
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Joined: Thu Oct 17, 2019 12:19 am

powered attic fan humidistat/thermostat control

Thu Oct 17, 2019 12:50 am

I recently had a powered attic fan installed in my roof to help pull heat and humidity out of the attic. This is a basic fan that can be purchased at Home Depot/Lowes etc. that comes with a Ventamatic Duostat humidistat/thermostat controller installed on it. Since the Duostat installs in the attic it makes it difficult to make any adjustments so I was wanting to find a way to setup a Rpi that allows me to make those adjustments i.e. the humidity or temperature threshold when the fan turns on/off via iphone, web, or other means that don't require me to climb in the attic.

With the Duostat I was assuming I would need to bypass that altogether unless there's a way to pull the data from the Duostat sensors already installed. Another thought, I have a SensorPush installed in the attic that already provides humidity and temperature data to the app on my phone and wasn't sure if the Rpi with the right API would be able to utilize that info regarding humidity/temp.

If there's projects already in progress that is along these lines point me in the right direction :D

Thanks

klricks
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Joined: Sat Jan 12, 2013 3:01 am
Location: Grants Pass, OR, USA
Contact: Website

Re: powered attic fan humidistat/thermostat control

Thu Oct 17, 2019 3:05 pm

Bogartz wrote:
Thu Oct 17, 2019 12:50 am
I recently had a powered attic fan installed in my roof to help pull heat and humidity out of the attic. This is a basic fan that can be purchased at Home Depot/Lowes etc. that comes with a Ventamatic Duostat humidistat/thermostat controller installed on it. Since the Duostat installs in the attic it makes it difficult to make any adjustments so I was wanting to find a way to setup a Rpi that allows me to make those adjustments i.e. the humidity or temperature threshold when the fan turns on/off via iphone, web, or other means that don't require me to climb in the attic.

With the Duostat I was assuming I would need to bypass that altogether unless there's a way to pull the data from the Duostat sensors already installed. Another thought, I have a SensorPush installed in the attic that already provides humidity and temperature data to the app on my phone and wasn't sure if the Rpi with the right API would be able to utilize that info regarding humidity/temp.

If there's projects already in progress that is along these lines point me in the right direction :D

Thanks
Normally an attic fan does not need constant adjustments. Once set you pretty much leave it alone. With my fan, I get up into my attic 2x a year.... Summer to turn it on and winter to turn it off. Though my controller is temperature only.

The Duostat is a electrical / mechanical (analog) passive type switch and does not have digitally readable sensors: https://bvc.com/xxduostat-replacement-a ... ntrol.html See photo of inside the unit.

The Duostat could be replaced with a solid state relay under control of the RPi with appropriate sensors.

The RPi and a power source would likely need to be located in or near the attic.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

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Bogartz
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Re: powered attic fan humidistat/thermostat control

Fri Oct 18, 2019 10:47 pm

Yeah, agree the fan is almost a set it and forget it or at least for me as I won't have any reasons to turn my off. I've recently had some extreme moisture problems in my attic with a whole home humidifier running during the winter so I decided to add a fan to try to pull some of that out. Living in Colorado any moisture to add to the air is a relief.

This project was more of a fun/practice project to get some exposure to Rpi and also work on my coding which is helpful for my daily job :) I thought this way I could fine tune easier while I monitor the moisture over the winter to prevent any more mishaps up there.
klricks wrote: The Duostat could be replaced with a solid state relay under control of the RPi with appropriate sensors.
I think I saw some reference to an SSR and DHT sensors which seemed what was being used for temperature and humidity.
klricks wrote: The RPi and a power source would likely need to be located in or near the attic.
I added an outlet in the attic last year to plug a floor fan in to dry out the deckboards as that was how bad the moisture was up there. I daisy-chained into that for the attic fan power so I would have access to a power source for the Rpi.

I think now I just need to figure out what type of coding is required for this and what's the better language to use.

Thanks for the reply klricks

OmnIoT
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Re: powered attic fan humidistat/thermostat control

Mon Oct 21, 2019 9:11 am

Check out this video. It's a similar situation to what you describe. It's trivial to threshold on temperature vs light (as in the example). And as illustrated you'd be able to remotely monitor the temperature and control the fan manually if desired by using any of the many free cloud based MQTT dashboards. Unfortunately we were literally just in discussions with the SensorPush people last week to support their sensors, but they said to check back in a few months when they'll be further along on their next version. So, you'd need to get a sensor we already support (though we're in the process of adding support from 3-4 additional temp sensors in the next few weeks). Anyway, if you're interested follow up here and I'll be happy to help you along.

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Bogartz
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Re: powered attic fan humidistat/thermostat control

Sun Oct 27, 2019 3:33 pm

Thanks OmnIoT, this is good stuff and would be very helpful with my project. I'll have to keep my eyes open for how things progress with sensors, I went with SensorPush since it had everything I needed to monitor my attic situation without having to actually go up in the attic. As mentioned, I thought this would be a good project to play around with and maybe expand on my programming capabilities :D Any info you might have I'm all ears.

OmnIoT
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Re: powered attic fan humidistat/thermostat control

Tue Oct 29, 2019 12:54 am

Hi Bogartz, If you can give me an idea of what your ideal scenario is I'd be happy to put together a quick config file for one of the supported sensors that you could then have a look at in the config utility (part of the install package you can download on the www.omniot.com website). While it obviously won't work without the different sensor, it would at least give you an idea of how the SoftHub works and some of it's capabilities. As I mentioned, we're going to be adding several new sensors soon and one in particular is very similar to the SensorPush and quite inexpensive. I can't really publish the names of the sensors as we usually give the sensor company a chance to look over the integration before releasing it, but if you send me a PM I can fill you in if you're interested... Anyway, anything I can answer, let me know. Thx...

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Bogartz
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Re: powered attic fan humidistat/thermostat control

Sun Nov 10, 2019 1:25 am

The ideal scenario is simple, I think lol. It really boils down to just a simple fun project that would give me some Rpi exposure and potentially some coding. I do a lot of software testing at work and look at a lot of code, but don't really get to write code so I thought this would be a fun and simple project with no real dependencies or requirements to have it completed in a specific timeline. Long term maybe a mobile app or a web app just because and maybe for logging temp/humidity data. I didn't want to run wiring to the living space for an on/off switch and access to the attic is a little painful because I can't install a pull down ladder without some major renovation, so I have to drag a step ladder up stairs. So with all of that info that's why I had this idea :D

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