Insulated Whole House Fan

created by petewill , updated by hek

Overview

Not sure how much interest there will be in this project but I thought I'd post it in case there are any other people out there that want to make a whole house fan. This projects is for an insulated (R30), automated (using MySensors of course) whole house fan. The purpose of the fan is to vent the hot air in your house out of the attic while drawing cooler air from outside into the house. I live in a climate with hot days and cool nights so this works great for me. The problem is most attic fans that aren't $1,000+ don't have any insulation so during the hot days they allow your house to heat up much faster than it should. So, I decided to see if I could build one, and automate it of course. :)

Here is a short video going over the functionality:

Wiring diagram

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I ended up not having enough space in the code for the SD card but this is how to wire it up if you did want to use it. You can also just leave it wired like this even if you don't use the SD card. Alternately you can use the yellow pins on the other side with the same connections and resistors (except for the SD wiring). enter image description here

Code Notes

The code is available from the "Source Code" tab above. It is still currently for MySensors 1.5. I will update it to 2.0 soon.

  • Most things that may need to be customized (motor stall values, close timing etc.) are at the top
  • The LCD uses the Adafruit_GFX & Adafruit_ST7735 libraries. You will need to download these and add them to your libraries folder (or use the Library Manager).
  • The code is too large to have debugging enabled and the LCD. Comment out debugging after you are finished testing.

Parts List

Click on the BOM tab at the top Note: Some of these things are probably only sold in the USA but hopefully it will give you something to base it on if you're in another country

Building

Here are some pictures from the build. I have also created the box as a 3D rendering in SketchUp (.skp) so you can get the dimensions of the box or if you want to make any customizations. The file is available on the "Design Files" tab.

It's important to get the box and drawer slides as square and level as possible so the cover operates as smooth as possible (then you don't need a big motor).

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I cut 1/2" strips of wood at 45 degree angles that will be used to help seal the slide. Install these perfectly level otherwise the cover won't close properly. enter image description here

Making the slide cover: Glue the foam board for the cover enter image description here

The wood on the sides will be used to attach the drawer slides enter image description here

Make sure everything is square and level enter image description here

Glue and clamp enter image description here

Attach V-Seal weather stripping enter image description here

Install drawer slides. These need to be installed as level as possible. enter image description here

The cover installed. Notice the space between the top of the wood. This is for the starting collar. enter image description here

The cover should fit tight and square in the back of the box. enter image description here

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Install the starting collar for the duct work. enter image description here

Hollow out a slot in the foam so a piece of wood can be inserted. This will be used to attach the wood used for the threaded rod. enter image description here

Make sure to use glue enter image description here

Screw in a piece of wood that will be used for the threaded rod. enter image description here

Screw in threaded insert enter image description here

The threaded rod was slightly smaller than the bearing hole so I used a plastic wall anchor as a shim. enter image description here

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Install cover and limit switches enter image description here

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Here is what the motor, Arduino, etc looks like enter image description here

I shimmed the motor and board so if they heat up there won't be a fire :) enter image description here

The relay and current sensor in the fan electrical box enter image description here

A blurry picture of the final install enter image description here

The LCD enter image description here

Images

Design Files

NameSize# Downloads
Whole House Fan Model.skp407.39 kB204

Source Code

NameSize# Downloads
WholeHouseFan.ino26.71 kB493

Bill of Material

QtyDescriptionLink
13013 CFM Quiet Cool Fanhttp://www.homedepot.com/p/QuietCool-Professional-3013-CFM-P...
116 in. x 12 ft. Insulated Flexible Ducthttp://www.homedepot.com/p/Speedi-Products-16-in-x-12-ft-Ins...
116 in. Starting Collarhttp://www.homedepot.com/p/Master-Flow-16-in-Starting-Collar...
1Strap for fan mountinghttp://www.harborfreight.com/400-lb-capacity-1-in-x-15-ft-ra...
115/32 OSB - 8' x 4' sheet (for fan box)http://www.homedepot.com/p/7-16-in-x-48-in-x-8ft-Oriented-St...
1Insulation (I used a 4' x 8' sheet)http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x...
116" Air Intake Grill (needs to be cut)http://www.homedepot.com/p/Lithonia-Lighting-White-Eggcrate-...
1V-Seal Weather Striphttp://www.homedepot.com/p/Frost-King-E-O-7-8-in-x-17-ft-Sel...
116 in. Full Extension Ball Bearing Side Mount Drawer Slidehttp://www.homedepot.com/p/Liberty-16-in-Full-Extension-Ball...
11/4" Pillow Block Ball BearingEbay: New Zinc Alloy Diameter 8mm Bore Ball Bearing Pillow B...
11/4" Threaded Rodhttp://www.homedepot.com/p/Everbilt-1-4-in-x-24-in-Zinc-Thre...
1Construction adhesive for insulationhttp://www.homedepot.com/p/Loctite-PL-Premium-10-fl-oz-Polyu...
11/4 in. Threaded Inserthttp://www.rockler.com/threaded-brass-inserts-select-size
1Arduino Pro Minihttps://www.mysensors.org/store#arduinos
1NRF24L01+https://www.mysensors.org/store#radios
1ACS712 - 30 Amp (for Fan)https://www.mysensors.org/store#power
1ACS712 - 5 Amp (for cover motor)https://www.mysensors.org/store#power
11 Channel 5V Relayhttps://www.mysensors.org/store#relays
1DHT22https://www.mysensors.org/store#temperature
1L298N Dual H Bridge Stepper Motor Drive Controller BoardEbay: Dual H Bridge Stepper Motor Drive Controller Board Mod...
11.8" TFT LCD DisplayEbay: 1.8inch Serial SPI TFT LCD Module Display + PCB Adapte...
51K Resistorshttps://www.mysensors.org/store#components
14.7k Resistorhttps://www.mysensors.org/store#components
1Microwave Radar Sensor 4-8M 180°Ebay: Microwave Radar Sensor 4-8M 180°LED Lamp Smart Switch ...
1Momentary push button switchhttp://www.ebay.com/itm/100Pcs-6x6mmx9-5mm-PCB-Momentary-Tac...
2Limit switchesEbay: 10pcs New KW12-3 Mini Switch Micro Roller Lever Arm No...
24.7uF Capacitorshttps://www.mysensors.org/store#components
2.1uF Capacitorshttps://www.mysensors.org/store#components
1Small wire for attaching duct to fan
1600RPM DC Motor
11/4" fuel line (for coupling to threaded rod)

Gateways

Sensors & Actuators

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