Sounds like I need to do some research into the relative particle=20
sizes.  The project is not an order yet.  They just want a ballpark=20
estimate on what it would take.
David...

On 18/04/2012 8:50 AM, Brendan Gillatt wrote:
> IIRC a smoke alarm I pulled apart (same principle but at an angle more
> like 45 deg) was constructed with a standard phototransistor and LED.
> The principle is sound but the issue is one of sensitivity. The
> reflectivity of smog particles is likely to be a lot lower than that
> of smoke from a nearby fire (lower concentration and probably lower
> particle size). Constructing the plastic holder could be done by
> folding sheet metal or rapid prototyping.
--=20
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David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
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--=20
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