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  • Author Author: phoenixcomm
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Smarthab: Remote Sensing and Control .iii  Sensors

phoenixcomm

Lets say that my home has 2 bedrooms, 2.5 bathrooms, laundry, kitchen, Office, and a workroom(I like to tinker). So we are going to need six room controllers. So we will need several sensors in each of the rooms which in turn feed in the corresponding room controller. For starters, we will need to measure the temperature and humidity.  This can be handled by a DHT22 this is a serial device which simplifies integration.image

We need a way to talk to the user so we need some sort of display, and a few buttons to boot. each 'thermostat' talks to the room or area controller. So we need some sort of communications between the two devices, and the 'thermostat' needs a little smarts, why don't we use some sort of Arduino. For Prototyping I will use a Mega R3 but down the road I will most likely do my own small factor copper board. But on second thought I could use a TI MSP430 with K350QVG-S1 Kentec QVGA Display BoosterPack that has a 320 x 240 pixel display which is a touch screen as well.image

Also in each room there are fire/smoke detectors, which also connect to the room controller. In case of fire, the room controller shuts off the vents to/from the room, as not to feed the fire with fresh air, or to blow smoke through out the habitat.imageimage

Last but not least is the question of how much air is getting past lost to inefficiency of the filters? Answer: Two Mass-Flow Sensor just like your car but a bit smaller one before the filter and the other after it. This will give you the flow drop caused by a dirty filter(s).

Just a quick note you could also include a Honeywell Air Quality Sensor HPMA1150SO there kind of cool and they only cost about 40 bucks, they are a serial device so they are no brainer to install or code. If you are going to install this you also might install a Radon Gas detector a well. Even though these devices are not room related but more whole hab sensors I decided to include them here as well.

 

 

 

REVISIONS:

DateNote
7-3-19 Rewrote the last paragraph dealing with the mass-flow sensors.
7-4-19Added paragraph dealing with air quality sensor.
  • in reply to wonko_the_sane

    Yes, I was going with a differential pressure sensor across the filters. The sensors are monitored and logged every hour or so. After the fan gets up to speed and the plenum is pressurized. Since this is a smart house, some rooms or sections of the hab are turned off or on by remote plenum dampers/vents.

  • Unless I've misunderstood your arrangement, I think you want a differential pressure sensor across your filters. The pressure drop will increase over time with accumulation of dust, which results in either  your fans working harder to push the same amount of air or pushing less air for the same work.

    Having flow meters both sides of the filter shouldn't show any difference when compared due to conservation of mass. Except if you're recording flowrate over time, in which case 1 meter on one side or the other should be sufficient to show a decrease in flowrate due to dust buildup.

  • Those components should give you good environmental assessment and control.

     

    DAB