Summer Slowdown

gtk

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Has anyone besides me, noticed a decrease in the number of pics taken ?  I was changing a 24 roll expsosure every 10 days.  Now, I've gotten only 14 pics in over 2 weeks.

I think a lot of it has something to do with the heat, deer and critters must not be moving as much.  Maybe the sensor cant detect motion as well in 90+ weather.

One of my cams has started shooting off whole rolls of film in 2 days.  It's got to be the shadows/heat.  Funny thing is, it's been in the same place for 3 months now, and working fine...   But i remember, the earth changes it's rotation throughout the year....

Later...

Greg
 



Richard Webb

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gtk - Those PIR Sensors have me scratching my head.  My second roll was taken when the temperature up at our local reservoir was 101 -104 degrees, and I got 24 plank pictures during the first day out.  Today the boy and I purposely left the top window glass off for ventilation (the one that shows the picture count & flash mode), and it started raining as soon as we returned home.  We can't win.
 

Richard Webb

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gtk - This is a little circuit that I'm playing around with that I hope will turn off the the Cam during day light hours from dawn to dusk.  If I ever get it solved we wont have to worry about heat waves again. It uses Radio Shack Photocells (276-1657)

 

NC Bowhunter

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That sounds like a good plan, Richard.  You could even try to build one with a temp sensor that would turn the camera off at a specific temperature.  It would probably be too complicated, but it might be worth a shot.

I'm glad I don't have to worry about temps in the 100s where I put my camera.  Good luck with the circuit.
 

Archilochus

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Hi Richard,
Nice looking drawing - what are you using to draw your circuits?
>>>>>>
It looks like the circuit will work, but seems like it would use a fair amount of current when enabled as it will have to energize the relay coil continuously when dark.  The current through the 4k7 resistor and LDR when illuminated (disabled) will also present a fair drain on the batts.  I had an idea that I think will work for daytime disabling the RS 49-425, but I've lent out this camera so I can't experiment on it at the moment.  My idea is similar to yours, but uses the "Q1" already on the RS 49-425s PC board and pulls its base low when illuminated.  If interested check out
http://geocities.com/archilochus57  Look at the section with the Day/Night Sensor.  I've added a bit explaining this idea along with a schematic pic.  Let me know if you have any luck with this idea, as I'd like to add this feature to my cam (when I get it back!)

NC Bow....This same idea could possibly be used for temperature disabling too - just replace the LDR with a thermistor (temp sensitive resistor).

Archilochus
 

Richard Webb

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Sorry about the typo on the resistor.  "4K7" should be "4.7K", because it's near the OV of the transistor.  I'll start over:



The idea is that light causes low resistance in the Radio Shack Photocells (276-1657), therefore the junction of the photo resistor and the 4.7K resistor is near OV. The node only needs to be below the turn on point of the transistor. It will take a little experimentation to find the resistance that shuts on & off at dusk & dawn. I could be wasting power all day long, but not if I use the 9 v from the speaker to power the circuit.  That brings us back to the singing relay problem, but I will try a half wave rectifier with our 1N4001 that we use across the relay.  I couldn't find a mini 100uF 16 volt electrolytic capacitor at Radio Shack, and the large ones wont fit in Jon's mini cam.  Below is the singing relay rectifier circuit:

 

gtk

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Question:  If I am using the MS20 sensor, couldn't I just put in in "auto" mode.  I think it has a daylight sensor, and doesn't auto-mode make it work only in nightime ?

Thanks...
 

Richard Webb

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gtk - Good question. It that's all it takes for night only operation, I have 4 ea of those 6 volt lantern batteries left over from my Y2K Preparedness, and could use them to power a MS-20.  
 

Archilochus

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Hi Richard,
I seeee! (slap ofthe forhead)  - I misunderstood your diagram - I was thinking that you were going to have a second relay that broke the connection between your first relay and the cameras shutter wires.
The 4.7k resistor and the illuminated photoresistor will still present a fair current drain.  If I remember, the RS photoresistors have a resistance of ~ 4k when fully illuminated.  So 4.7 + 4 =8.7k    5V / 8.7k = 574uA  The 49-425 consumes only ~125uA in "chime mode", so that would be a large increase in power consumption.  The current from B to E of the transistor will also be a drain on the batts.
Maybe if a MOSFET was used instead of an NPN bipolar transistor, this idea could be accomplished with much less power consumed.  Now I see how this idea could also be used with the one transistor timer for long period picture delays.
I wonder if it would work to use two or three transistors in series - sort of like a TTL 'AND' gate - and have different inputs that can disable triggering - say a daytime disable, a temperature disable, and a picture interval timer disable?
If you insert a ~ 5k trimmer - one trimmer pin to the 4k7 resistor, one pin to the photoresistor, and the wiper to the base of the transistor - this would allow you to adjust the light level at which the circuit disables.
>>>
By the way - it's fairly common in schematics to use the multiplier in place of a decimal point - so 4.7k is commonly replaced with 4k7  This prevents misreading of schematic part values as the decimal points sometimes disappear when a schematic is printed.

Archilochus
 

Richard Webb

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Hi Arch - You were right the first time, and I plan to use two relays. When I had the walk light hooked up together with he shutter I noticed that there is a time lapse between the time that the walk light comes on and the the time that the camera clicks. I plan to use that time frame to activate another relay turning off something. So, the only time that the Day/Night circuit will draw current will be when the speaker IC is high. However, everything is on hold until I check out the temperature sensors at Fry's, because it's temperature that I'm after not day/night.  I'll post my drawing symbols & method on another thread.
 

Tinhorn

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I experiemented with the MS20's internal Dark Detector but it didn't work very well, it was still pretty light out and would still trigger.

Here is a method for nite-time/day-time only pix's if using a timer with a TLC555

I built this a year or so ago, used a switch to select which mode to use but I can't find the Schematic.   It was based on these circuits tho (from RS's Mimms Book)

I had to "Fiddle" with the Variable Resistor values I remember, but it worked pretty good.  Making Pin 4 "Low" will shut-off the IC so it don't trigger....

 

Archilochus

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I clipped some links and information about higher temperature PIR use.
From the web-site of  NAiS < http://www.nais-e.com/ > These are PDF download links:
http://ctlgserv.mew.co.jp/acg/tech/bltn_eng/e_pdf/p55.pdf
This site has other PIR sensor info too - check their index at:
http://ctlgserv.mew.co.jp/acg/tech/bltn_eng/
From the web-site of a research grade trail-cam company called Crow Systems
< http://crowsystems.hypermart.net/cameras.htm >

-----clipped text follows---------
.
An object that is nearly equal in temperature to its surroundings will probably not be detected - no matter how it moves through the detection area. A very small object will be difficult to detect - regardless of its body temperature - unless it is very close to the sensor.
Therefore: An objects surface temperature, size, speed of movement, distance from sensor, and difference in temperature from its background all play a part in determining a PIR sensors detection range. .
NOTE: A large object - such as a person, bear, deer, etc, - will often trigger a PIR sensor even when the ambient temperature is
almost equal to the objects average body temperature.  Why? - Because a large object is almost never uniform in temperature across its entire surface. Therefore it acts as its own background and often supplies enough temperature difference to trigger the sensor.  .
Disadvantages: Susceptible to false triggering due to improper set-up, loss of sensitivity when subject and ambient temperature are close, can not detect very slow-moving, small, or cold-bodied objects, not very accurate - subject could be offset to one side of picture.



(Edited by Archilochus at 1:28 pm on July 27, 2002)
 

Archilochus

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Hi Richard,
Guess I got really confused!
So - just to get it straight - pin#2 from the big IC going high when motion is detected will operate the first relay (call it the camera relay)   Pin #2 will also drive the base of the transistor through the 4.7k resistor and also supply a positive voltage to the second relay coil (call it the disable relay).   If the photoresistor is dark, the transistor base will be driven above the switching voltage and will start conducting.  Current will flow through the 'disable' relay coil, closing the circuit and allowing the 'camera' relay to close the shutter contacts.  If the photoresistor is illuminated, the base of the transistor will remain below the switching point, and the 'disable' relay will not be energized and no picture will be taken.
Did I get it right this time?
Sounds like a good idea.  I like the fact that it uses no power when idle.  The only remaining issue is if the IC can handle the current.  But you mentioned using the rectifed speaker output to drive the relays, so maybe that's not a problem.
Did you ever have any luck with Tinhorns' idea to use the Pin #2 output to drive the "Q1" that is already on the board?

Archilochus

PS.... Some of that last post got cut off for some reason..Here's the rest:
http://www.trailmaster.com/
A Passive infrared monitor by its nature cannot tell the difference between an elephant, a rabbit, and a blowing bush that has been warmed by the sun. (Although it is commonly said that a passive infrared monitor works on BODY HEAT and MOTION, it really works on TEMPERATURE DIFFERENTIALS and MOTION. If foliage has been warmed by the sun and is moving in the breeze in front of a passive infrared monitor, it can register like a moving warm-blooded animal.)
 

Richard Webb

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Hi Arch - You have it right this time, but I chickened-out when I thought about putting that much load (574uA) on Pin #2 of the large IC. (thanks for warning me) What I'm planning now is to put everything on the speaker wires. That way, if I fry the small IC I still have a PIR.  Tinhorn's idea worked okay, but I still would be fooling around with pin #2 of the large IC. It remains to be seen whither or not #2 will stand up to the Reed Relay. The little Rectifier Circuit takes the buzz out out of the relay, and the large Radio Shack Photo Resistor in the metal case works perfectly with the 4.7K Resistor. I was walking around the house with a 9 v battery, and it seems to like outdoors light better than my desk lamp. Maybe tomorrow I will have time?  Today I stopped at the local electronics store, and they had one of your 4538B Timers. So now I will have something to play with after I get the light sensor working.  
 


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