Home ventilation: remote control and automation. Part 2

So I've got fresh air in my cabinet. Everything works fine.

But what about bedroom? It's one third of our life time we're sleeping and it must be comfortable!

The challenge here is I need doors and windows CLOSED (first floor in Russia is awful really). And ventilation must not generate noise by itself.

First attempt

I had an opportunity to modify window leaf and did so. Plan was: remove outer and inner glass, change them to thicker but shorter pieces and made a corridor for air between, and insert paper air filter in the middle. But sadly paper air filter is not a noise isolator at all. So closed window sounded just like opened window, and it was very noisy.

Other part of ventilation system was modifying door. I made rectangular hole in it and installed some low-noise ventilators in one of standard louver cases. Also added some automation: PWM and temperature monitoring.

Anyway, it wasn't working as expected.

Then I removed old window and installed noise-proof one. Now I really won't open this window (it's QUIET at least) so I needed fresh air from somewhere else...

not very accurate but works :)

But now we have half of a problem solved! Air out channel set and works good. And what about air in? Well, I've got a whole room of fresh air behind inner wall. Let’s DRILL!

How to drill clean

Simple. We will need: cheapest plastic bucket, lots of masking tape, big knife and hoover. Make a big hole in bucket's bottom (do not remove all the bottom – we need some margins for dust stopping). Make a small hole on bucket's side and insert hoover's pipe. Use masking tape to bind it all together and to wall. Insert drill into hole, turn on hover and drill.

So, we have vent-channel 100 mm wide. For bedroom ventilation I decided to use S&P Silent 100 fan. It has low noise characteristic – 30 dB and high working static pressure – about 50 Pa.

For automation and remote control – "Mini-Monster" is my favorite :). With it can turn ventilation on and off just lying on my bed and also can change fan speed. Changing speed is really useful cause, as I figured out after some days of use, in small room 30 dB is a little too much (some interesting things about noise see below)

"Mini-Monster" has two 16-bit PWM channels. Trouble is, with them we can control only DC up to 24 V. And what we need is to control AC 220V. Solution is simple. For dimming DC we need a power key, and for dimming AC there is a simple schema with four elements in it. 

For all this stuff designed and 3d-printed a case (beta now). Fan can be connected with original power cord to control block, and block itself can be disassembled at any time if necessary.

So, I've got what I needed – now bedroom ventilation is present and works perfectly. It's really good to feel light breeze when falling asleep. This ventilation system can maintain 650 ppm CO2 at full speed. It feels comfortable. Also I'm using silent mode, it's about a half of rotation speed and maintains 700 ppm CO2 for one adult. System can be controlled from smartphone, I just made shortcuts. Planning to automate system by CO2 level and add sleep trigger (to turn full speed automatically when catch off). It all can be done with "Mini-Monster"

About fan noise, installing and speed

As I mentioned, 30 dB for a small and silent room is really too much. There are two types of noise – air noise and motor vibration. I think second type can be dealt with by installing fan with some vibro-damping material. I used silicone sealant for this, but it looks like it's not elastic enough. So when I'm tired of all noises I just use low fan's speed and enjoy silence :)