My Camera Design and Some Security Ideas

Jaggermax

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Well guys, my design for my new cam is finally coming along.  I decided to use an ATMEL AVR microcontroller so I could have a lot more control over the operation of my cam.  I had to many things I wanted my cam to do and it forced me to use a microcontroller.  After many sleepless nights of head scratching, burning up boards, and trying to find electronic components, I am finally getting somewhere.  I built my first board and am writing software for it now.  Hopefully, I will be able to post some pics in a few weeks to let you all see the innards of it.  

I have been reading a lot of your posts about the security of the cameras and I am implementing an idea on mine which may solve some of these problems.  

First, I am using a 14 guage NEMA electrical enclosure with a key lock on the front (I work for an ATM manufacturer and I am using some high security ATM locks).  

Second, I am going to weld on some I bolts to each side where a chain will be run to attach it to the tree.  

Third, I have a tilt switch installed on the microcontroller board inside the enclosure.  If someone tries to pry the door open or cuts the chain off, the tilt switch will throw when the unit tilts more than 20 degrees which will actuate a 105db SonAlert piezo siren.  I powered this siren up yesterday and almost crapped in my pants!!  It is some kind of loud and only pulls 20ma of power off of a small 12 volt battery.  I also have a keypad on the side of the box so that you must enter a password to turn off the alarm before you open it. Even without a microcontroller based camera, the tilt sensor should work well with some of your designs.  

Anyway, a few other features I am incorperating are:  

* 500 event time/date log in memory
* daytime, night time, or both operation
* Programmable PIR distance detection (10,30,50, or 70 feet).  ( This is accomplished by controlling the sensitivity on the PIR op amp circuit) I am also adding a function where the you can set the nightime trigger distance so that deer walking past the flash distance will not trigger the camera, but during the day, it will automatically set the PIR to a further distance.  
* Programmable delay setting between pictures of 1,3,5,10 and 30 minutes.
* And finally a battery low indicator.  

I want to thank yall all for the good tips and pointers.  This site has been a real help.  
 



Welby

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Hmmmm....one word comes immediately to mind:

WOWWWWW!!!!!

Hope the wind doesn't get your camera tree to sway too much!!

Sounds like a combination of a lot of great ideas.
 

Jaggermax

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At first I was worried about the wind blowing the box around, but I think I have a fix for it.  Instead of a 10 degree tilt sensor, I will just go with a 30 degree sensor.  If the wind manages to blow a tree 30 degrees from vertical, then I figure I have lost the unit anyway because it most likely being sucked up by a tornado.  


The funny thing is that at first, I was simply going to design a basic trail moniter that recorded the time and date of the trigger.  It was not even going to have a camera attached.  However, the engineers I work with got wind of what I was doing and they then became involved.  It has really started to mushroom to more than what I originally intended. But it is still fun as hell to work on it.  


I am going to post the schematic of the circuit and 3D model of the entire assembly this week for those of you that wish to see it.  I just have to figure out how to post a TIF file.  
 

Archilochus

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Hi Jaggermax,
Sounds like a great system!
It's much like the trail-cams I'd LIKE to build, but I have no experience with micro-controllers.

I took the lazy mans approach to data logging.... Just popped in a HOBO data logger.

Archilochus
 

Archilochus

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Hi Jaggermax,
Sounds like a great system!
It's much like the trail-cams I'd LIKE to build, but I have no experience with micro-controllers.

I took the lazy mans approach to data logging.... Just popped in a HOBO data logger.

Trevor..... Great minds discuss.....Trail Cams!!

Archilochus
 

Archilochus

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Hi Jaggermax,
Sounds like a great system!
It's much like the trail-cams I'd LIKE to build, but I have no experience with micro-controllers.

I took the lazy mans approach to data logging.... Just popped in a HOBO data logger.

Trevor..... Great minds discuss.....Trail Cams!!

Archilochus
 

Archilochus

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Hi Jaggermax,
Excuse that triple post... Slip o' the mouse.

I thought of another feature you might add to your circuit.  This is one I tried figuring out for my cams, but the math gave me a headache.

Since you'll have selectable sensitivity specified in feet of maximum detection distance (rather than just "hi" or "low" ), you might need to add some temperature compensation in your gain controller.  Otherwise, say you select the setting on your sensor to have a detection distance of 25 feet (assuming you calibrate your circuit at +75 F), but then the ambient temperature rises to +90 F, your actual sensitivity will decrease.  On the other side, if the temp drops your sensitivity will increase.

I gave up on this problem.  If you come up with any relatively simple solutions, I'd love to see the schematics.

By the way... Do you have spec sheets for those sensors you purchased from China??

Archilochus
 

Jaggermax

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Great Idea Arc!!  It never occured to me.  What I can do is simply connect a digital temperature IC chip like those made by Dallas Semi and constantly monitor the temp.  As the temperature starts to go up (or down), I can automatically increase or decrease the sensitivity of the PIR op amp circuit  in proportion to the temperature.  I am using a digital potentiometer to control the PIR op amp sensitivity so it can all be automatic. Do any of you know where I can find a temperature VS sensitivity chart for the RE200B?  

Also, I sent a $300 wire payment to Waitrony for the sensors and lenses, and guess what, they never sent them.  Guess they are still pissed about our spy plane.  Not a whole hell of a lot I can do about it though.  I also ordered some samples from Nicera, and they have not arrived yet either after three months.  Guess I will have to stick to the good ole RE200B.  By the way, Marlin P Jones and Associates have the RE200B for $3.25 each for those of you wanting to make your own circuit.  Part number 7250-MI at http://www.mpja.com.  

(Edited by Jaggermax at 7:54 pm on May 15, 2001)
 

ToddP

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Re the alarm feature.

It might be possible to do the same thing with one of those "personal alarms" that they sell at RS and  a mercury switch, depending on how small the make them.   I spent a summer during college working for a treatment plant.  We would use mercury buoys in a tank to trigger a pump.  When the fluid level reached a height that tilted the mercury swithched buoy, hanging by a cord, sideways... the pump would be turned on reducing the fluid level.

I might have to check on this.

Todd
 

Archilochus

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Hi Jaggermax,
I never thought of using a digital potentiometer!  I just have an audio pot to control sensitivity (set from Max to Min.....Damn the temp compensation!).  But now that I'm thinking about temp compensation again, I feel that migraine coming back.

The specs for temperature VS sensitivity are tough to find.  I received some samples of the Heimann (now Perkin-Elmer) part # LHI 968 that came all the way from their lab in Germany.  Each of the 5 samples had 4 pages of test results given for it.  There was not a single mention of temperature VS sensitivity.  They did note that their test rig used a temp compensation circuit, but gave no specifics.

You might try posting this question in a relevant newsgroup.

Too bad about the parts from China.... They sounded perfect.

Archilochus
 

Welby

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Archilochus?  Jaggermax?  You boys ARE still building cameras, right?  This is beginning to sound like a NASA forum.

Man, here I am just proud to be getting pictures and you guys are worrying about monitoring the temperature.

I can't wait to see what your cameras look like.
 

Archilochus

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Cameras??  I thought this was the NOAA discussion forum!  ;)
>>>>>
While the rest of us can conveniently ignore temperature compensation, Jaggermax needs to account for it because he wants to set his PIR sensitivity adjustment by specifying how many feet the sensors range will be.
Not only does he need to account for any temperature-related changes in the electronic devices used in his circuit, but he'll also need to have the circuit automatically adjust for varying temperature differentials between ambient and subject temperatures.

To add to the difficulty....If the target area the sensor is aimed at is warmed by the sun - but the sensor itself is in a cool, shaded spot - the temp compensation circuit will think it is cooler out than the actual ambient temp of the target area.  So just when the sensor needs to be BOOSTING sensitivity to account for reduced subject/ambient temp differential, it will actually be REDUCING sensitivity.

Then......when you figure resistors, capacitors, IC's, PIR elements, Etc., all have different temp coefficients (some negative, others positive) - and then you throw in that a mammals surface temp will vary with ambient temperature change, toss in to the equation any temp-related changes that might occur in the transmissive qualities of the optics used......

The calculations boggle the mind.

Now I gotta go get some aspirin.

Archilochus
 

Jaggermax

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"Boy O Boy" Arc, you just had to add a few more gear grinding calculations to the problem did'nt you.  Aspirin ain't going to cut it with me, I need some Rolaids!  Therefore I have decided to take this approach.  

You are absolutely correct about all of the tolerance and temperature stackups so I have decided to do somthing very obvious.  Instead of trying to lower the sensitivity range of the PIR for night time shots, I have decided to add an additional flash strobe external to the enclosure!  That way I can get extra flash range on my night shots.  I bought a strobe flash kit and played around with it last night.  It actually added about 20 additional feet to the flash distance of my Fuji Discovery 90!  
 

NC Bowhunter

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Now you guys just need to find a digital camera that can be modified for this project.  Then you can figure out to make it dial up to the internet and  automatically upload each picture right after it takes it.  It sounded like you were running out of things to add to this one, so I thought I would give you a new idea.  Now that would be a cool camera!  
 

Richard Webb

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A Portable Slow Scan Television will do the job.  Kenwood has a nice little image scan converter, CCD Camera, and LCD Monitor for $584.00 (HRO has it discounted down to $399.95)  You'll need a ham radio ticket to operate it, and Jesse can help you get started.  (I've had my ticket so long that I forgot the questions on the test)  Here is the URL:

http://www.kenwood.net/products/index.cfm?...ateur&ID=51  
 

Archilochus

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ARRRRrrGggGGHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!

>>>>>>>

I have actually read about a system like this in some USFWS report. VERY expensive!  I think maybe made by Sandpiper Technologies??

Archilochus
 

Richard Webb

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Arch,

Yes. the government always pays too much.  The Portable SSTV I mentioned has the PG-4 mobile connection cable option for $49.00  From there you can pick up an old crystal VHF Ham Radio at a swap meet for less than $100, and start collection junk radios until you have a repeater up on a mountain top broadcasting your game pics all over creation.  With a few of these SSTV positioned you would know exactly where that big buck is bedded down for the day.  P.S.  I'm still working on my first Owl PF.
 

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