So expanding on my knowledge in PIC programming and some excellent components that are reasonably priced and considered excellent alternatives to industrial.. on mostly somewhat out dated and very expensive equipment.

Here I have a prototype of a Particle Sensor that is sensitive to 0.1mg per cubic metre (mg/m3) and a Dallas OneWire temperature sensor.




Using this prototype I can add more features with temperature sensors as far away as 50metres using Dallas onewire technology up to 10-20 sensors. The only limit it space on the LCD. All data can be related via a serial output or averaged out.. etc. Chemical sensors can be added such as ozone, diesel, co2 and some others. Units can even be stand alone running on WIFI or LAN with built in webserver.

The cost of expanding this prototype is only limited by how much you want to spend.

Here is a quick demonstration of the prototype. It updates every 800ms because the temperature sensor need 800ms to send/receive data. The actual particle sensor can update as fast as 10ms. So can the temperature but an external onewire ic is required to drive the onewire network. It is all a matter of needs and cost again.

Private youtube link not available for public search.


http://www.youtube.com/watch?v=DGLmh4Sa5Oc


I suspect that this version demonstrated in the video, in its alpha stage; built onto a PCB with connectors and a nice housing could be sold for about £80 ~ £120.

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nice idea but its all ready been invented and the cost for some of these go for less then $150

Yes but satisfaction in this case is PRICELESS. Nice job, ppumkin !

BTW the sensor you used is basend on simple Tyndall or more like other smoke detectors ?

@craig - Yea there are some out there. This prototype however can be expanded to do various things. for eg - control your climate via iPhone - while you are 100kms away.. and so on. and the price wont really shoot up too much. PS; The actual parts for this are pretty cheap 'except particle counter' from my best friend in China Just the time and development that costs.

@BlackST - Satisfaction is priceless

Its not based on Tyndall effect sensors found in common smoke detectors; but.... I am sure they could also be of use. This is a infraRed based device
" infrared emitting diode and a phototransistor are diagonally arranged ... to allow it to detect the reflected light of dust in air"
Its sensitivity is 0.1mg/m3 and is commonly used in air purifier systems.
I just used the smoke of a candle to demonstrate that it actually counts particles (1ms modulation) ;

It counts an average of 200mg/m3 in my study. So hopefully some of my friends can get some nice low readings in their custom boxes

The only drawback is . It cant tell me the size of particles.

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Was just reading on how to calculate the mg/m3 and came across a health regulatory manuscript and found this.

"In office buildings, the average particulate concentration found in a non-smoking environment is 10 μg/m3. In smoking areas, it can range from 30 to 100 μg/m3."

My reading are 200mg/3 ;; or my code is naft somewhere or im about to die ...

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Here is a device by PolyEnvi:
http://digitalcommons.calpoly.edu/cgi/v ... ntext=eesp

"Our project consisted of designing and developing an inexpensive air quality sensor
for residential use. It measures dust, smoke, and ozone in the ambient air surrounding a
sensor enclosure; in addition, it measures levels of humidity and temperature."

The device has Ethernet and Wifi support, plus an LCD display. It also uses a PIC microcontroller. Production cost is claimed to be $150.

There is a circuit diagram in Appendix C.

According to the Sharp datasheet, the sensor's output voltage is a maximum at about 0.8 mg/m3, and the sensitivity is about 1.2V per 0.1 mg/m3.

Dust Sensor Module:
http://www.gr8tech-hk.com/pdf/DSM501A.pdf

Sharp dust sensor, GP2Y1001AU:
http://img.chipfind.ru/pdf/sharp/gp2y1001au.pdf

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@ppumkin,
then the problem is simply the method / sensor (had this feeling...). I made something different with some more complication that seem have reading comparable to commercial meters, but the cost is lower.

@fzakbar

Thanks. So that means that my reading is actually average 2.0mg/m3
Hmm.. ?
Need to check my code again somewhere too much multiplication.

And i cant seem to load that link from digital commons; will search it later. just saying its broken.



@BlackST ; does yours use a laser sensor or some sort?

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you have pm. One of the sensors is made in Italy !

Thanks BlackST. Will have to get some more stuff and try version 2

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