Perplexing Problem Part II

Eagle Eye

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Tinhorn, Brian I tried your suggestion and got it to work, kinda. Triggering was very unreliable. The X10 sensor really needs Hamiltoes comparator to be effective. The diagram below shows how I got it wired.
Hooked up as shown it will sit idle until motion is first sensed and will take the picture, but as soon as it times out it will retrigger itself. I have  tried disconnecting the sensor input but it will continue to cycle until I disconnect the battery.
I think the battery voltage on the trigger is the culprit, is there anyway around this?
 

Tinhorn

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Eagle Eye,

I'm going to make a "guess" on what's happening:

The guess is, that when JoeD's timer times out, the sudden voltage change as it resets is sending a PULSE into the power supply and this PULSE is causing the Comparator (or PIR) to trigger again, in a vicious cycle.  

JoeD's Timer draws so little a current I'm surprised this'd be a problem but sounds like it is.

Whats needed is power supply filtering to dampen out the pulse....

some things to try:

1.
remove the wire from JoeD's Timer, pin 1 to Batt (+) and then connect a diode's banded end to JoeD's Timer, pin 1 and the other end to battery (+)

This may "Block" the pulse from backing up into the power supply, but it will reduce the Batt Volts to JoeD's Timer by about a half volt, which may cause an under voltage problem

2.
add a 100uf cap to JoeD's Timer Pin 1 and the cap's (-) goes to batt (-)....install the cap as close as possible to JoeD's Timer pin1....

Add a 2nd cap whos value is .1 in parallel to the 100uf cap above (there won't be a +/- terminal on this cap) also installing this cap as close as possible to JoeD's Timer

3.
Don't connect the relay's coil directly to pin 5 but have pin 5's output run thru a diode into the relay coil (banded end connects to relay coil)  This will (mite) block any spike from backing up into JoeD's Timer, possibley causing a problem....

*******************************************

I also don't see a "protection" diode across the 5v reed relay coil in your drawing!  if it's not there, better install one, it's really needed, JoeD's Timer could be destroyed without it.....

Let us know what you find out

Tinhorn
 

Brian

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Eagle Eye,

Timer could be damaged or like Tinhorn says you could be getting a backfeed voltage from the switching of the relay.

You should find that the 2n3904 will work as well once you isolate the false triggering problem.

Brian
 

Eagle Eye

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 You guys are the best. Adding the diode between the 5 pin on JoeD's timer and relay did the trick. I've got it set up on my workbench in the basement and with the lights off its triggering out to about 30 ft. at 68 degrees.
 This should work well with the flash range of the Owl PF. Still got to build the housing but hope to be field testing soon.
 Also added the protection diode to the relay, its a wonder I didnt fry the chip as much tinkering as I have done on this.
 Couple more questions, can I use the super bright LED's with the 1k resistors, and where can I buy small waterproof  N/O pushbutton switches?
            THANKS......

 For anyone interested in the X10 sensor heres a couple of links to some interesting projects....
http://www.hometoys.com/tips.htm
http://www3.edgenet.net/lingling/xindex.html

(Edited by Eagle Eye at 9:28 pm on Dec. 3, 2001)
 

Tinhorn

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Eagle Eye

I don't know what voltage those LED's and 1K resistors require but I imagine they'll work.  If you can't find any weather proof Momentary Swithches, you can use a normal toggle switch with those rubber covers that RS sells, the switches don't have to be Momentary, you can just Toggle a regular lever switch if need be.  Also, some Lever switches are momentary too, they have a spring to return the lever, don't know if RS carries any of them or not tho......

BTW, what's those numbers on the Comparator you used, the pix is a little too hard to read.  Like Brian said, I'm sure the transistor setup would still work if it's any easier to solder on your board.

See Ya!

Tinhorn
 

Eagle Eye

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 Tinhorn, The number for the comparator is LT1017. This is the one Hamiltoe used. I had to order it from Radio Shack since they didnt stock it.
 Heres a picture of the finished board minus the chips and sensor input. Pretty simple if I can do it.
 

Tinhorn

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Wow, pretty simple is right, can't get much simpler than that

Tinhorn
 

Brian

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Eagle Eye,

Nice layout skills.  Most people do not take the time to tidey up a project like you have.  I bet your shop is probably neat too.

I am not sure what Micro JoeD used but all the ones I have been using will sink about 25ma max per I/O pin and that is pretty close to the draw of an LED.  If you are not sure what the turn on  voltage and current of the LED is then start the resistance high and work your way down until it turns on.  I would guess that 1k would be more than adequate.

Brian
 

hamiltoe

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Eagle Eye,
I'm glad you finally got it to work OK.  After having my X10 setup in the woods, I think the voltage adjustment on the camparator should be increased to maybe 0.7 Volts instead of 0.4 Volts.  I've been getting too many false triggering, mostly on sunny windy days.  I think that at 0.4 volts, it is too sensitive on these types of days.  I haven't made the changes yet, but plan to soon.  

Also, make sure to mask sensor's outside lens some.  I noticed that small critters walking almost under the unit are tripping it.  I can tell b/c I have my timers are set for 30 seconds and almost all of the empty photos are followed up by a second photo 1 minute later with a rabbit/raccoon/armadillo along the bottom of the photo.
 

Eagle Eye

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 Thanks for your help on this hamiltoe. I'll make the adjustment on the camparator and see what it does.
 I finished the cam today except for one switch. I decided to use one of the small mom-off-momentary switches , since I can get the rubber covers for these, to operate the timer/counter. Nobody in town had one so I had to order, be a few days before I can get it in the woods.
 

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