IR Sensor(If all else fails)




Archilochus

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Hi all,
I read in the newsgroup sci.electronics.design a while back that this schematic had some technical flaw.  I didn't see anything that looked wrong with it, but I'm no pro.  Maybe they fixed it.  I've been using low-power 'home-made' PIR's for my cams that are a combination of this circuit and a circuit taken from LSI Computer Systems web-site.  Check the data sheet for part# LS6501LP.  -  http://www.lsicsi.com
That part actually works well, but requires a 9 volt supply.

Archilochus
 

BamaNative

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Archilochus ,

Thanks for the link on that part.  I looked all over for a part like that and never found anything.  This should do the trick.  the circuit in the white paper look like it would work, although that means the timer control can still only take up to three minutes.  Is this a correct statement.  Are you adding a second stage to your delay timer.

Thanks again. Do you have any advice on the cheapest places to get these parts along with the PIR and fresnel lens.
 

Archilochus

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Hi BamaNative,
Are you referring to a time duration between taking pictures so that your film isn't used up quickly on one subject?  If so, on page 2 of the data sheets you'll find "Table 1" which shows the specs for the "Output Duration Timer as a Function of Timer Control Input Voltage".  It shows output durations selectable from about 30 seconds to 30 minutes.  Use "NPO", "COG", or at least "X7R" temperature rated capacitors for this and any other timing circuits, otherwise as ambient temps change your timing can shift dramatically!.

Use the RELAY output of the 6501 to negative-edge-trigger a non-retriggerable monostable (NOT the 555!!) such as a 4047B or 4538B.  Use a potentiometer to select a voltage at the "Timer Control Input".  The RELAY drive ouput going "LOW" triggers the 4047/4538 - which then turns your camera shutter relay "on" for a couple of seconds.  The 6501's RELAY drive output then stays low for the selected time period,  preventing the 4047/4538 from being triggered again (also preventing your camera from being triggered again).  The only way the 4047/4538 (and your camera) can be triggered again is when the 6501's RELAY drive output goes back "HI" and then falls "LOW" again when motion is once more detected.

It looks like this company has a newer version of this IC available - the 6511 - which can run off a 6 volt supply.  I never used this newer part, so don't know how well it works.  Looks like it has a more advanced "signal processor" to discriminate against false triggering.


I received the following list of distributors for LSI products:

Belco Electronics  Tel # 630-530-1105,  630-953-1115  194 Myrtle Ave, Elmhurst, IL

M-Tronics  Tel # 401-941-7400   1175 Post Rd.,  Warwick, RI

Pro-Formance Electronics  Tel# 1-800-776-0022   270 East Drive, Melburne, FL

Kadah Associates  Tel# 1-408-267-3711   1761 Meridian Ave,  San Jose, CA

US Digital Corp.  Tel# 1-360-696-2468    3800 N.E. 68th St, Suite A3, Vancouver, WA

Don't know who is cheapest as I just called LSI and asked for "engineering samples"

See the post "PIR Lenses" in this forum for PIR element and Fresnel lens suppliers.

Good Luck!,

Archilochus
 


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