Checking out a cam today takes 1 pic when pir is triped, then after a couple pics I have to switch to LED test then back to camera,then it will take pics again (1 at a time) then have to switch to test again. Only thing I can figure it is the read relay sticking. Need to check it with a tester seems like I seen posts on this problem before. Is there anything better than the relay to use to trip the camera.
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ArkansasElkHunter
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An optocoupler is a solid state device. it uses less current and won't stick.
about $0.40 each. ****** has some but he may only sell them with the low power mod kit for the ms20. otherwise check mouser or digikey. Radioshack may carry one I'm just not sure
about $0.40 each. ****** has some but he may only sell them with the low power mod kit for the ms20. otherwise check mouser or digikey. Radioshack may carry one I'm just not sure
u turned em
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AEH.....I've been wanting to ask this question. Can you tell us (those of us that are not electronically educated) what an optocoupler is, what it looks like, what it does, how it works, and how it replaces a relay. I understand the relays....just a "electro-magnetic switch". Just want to further my electronics learning. Thanks.
Archilochus
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That's a big ol' question ;-)
(VERY) Basically.... it's an LED and a light sensitive transistor (switch) in a convenient 4 pin package. When the LED is turned ON (make sure to use a current limiting resistor), the light from it then causes the light-sensitive transistor (switch) to start conducting (just like the relay closing creates a conductive path). The LED and transistor are completely isolated from each other electrically, so you can use the opto to safely switch a second, different circuit (the cameras shutter).
So you can think of them as optical - instead of electro-magnetic - switches.
The advantages are lower power, smaller size, lower cost, and no reverse voltage inductive spikes (ignore that last bit
NOTE: Don't use the parts available from Radio Shack stock. They probably won't work in many situations.
Also - you can get multiple optos in a single, larger package.
Try searching this forum about optos, opto-couplers, opto-isolators - for part #'s and how to use them.
For more detailed info, try a search at http://www.google.com with the search terms opto-coupler OR optocoupler OR opto-isolator OR optoisolator - should get TONS of hits.
(VERY) Basically.... it's an LED and a light sensitive transistor (switch) in a convenient 4 pin package. When the LED is turned ON (make sure to use a current limiting resistor), the light from it then causes the light-sensitive transistor (switch) to start conducting (just like the relay closing creates a conductive path). The LED and transistor are completely isolated from each other electrically, so you can use the opto to safely switch a second, different circuit (the cameras shutter).
So you can think of them as optical - instead of electro-magnetic - switches.
The advantages are lower power, smaller size, lower cost, and no reverse voltage inductive spikes (ignore that last bit
NOTE: Don't use the parts available from Radio Shack stock. They probably won't work in many situations.
Also - you can get multiple optos in a single, larger package.
Try searching this forum about optos, opto-couplers, opto-isolators - for part #'s and how to use them.
For more detailed info, try a search at http://www.google.com with the search terms opto-coupler OR optocoupler OR opto-isolator OR optoisolator - should get TONS of hits.
u turned em
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Thanks Arch.! Now I have furthured my electronics education some!:idea-blue: Are opto's. being used to replace the relays ON the MS20 boards, or are they part of some of the more advanced add-on boards such as Brian's boards which in turn replace the "gutted" portion of the MS20 boards? I'm getting a feel for this and can certainly see the advantage of using an opto., as well as considering adding my first delay/timer board. I'm just a little timid/intimidated by the electronics and mods. that need to be done.
I concur with the advice on the optocoupler... there's a lot to be said for having no moving parts.
One note regarding your original question about the relay sticking... a number of times during my years of playing with electronics, I've had relays start sticking. Most of the time it was because the core of the relay's electromagnet (or the reed "guts") became permanently magnetized making them inclined to stick. This can happen because you apply too much current (too much voltage) and the magnetic field becomes great enough to permanently alter the core and leave it magnetized; indeed, most of the times I've seen it happen were due to abuse (like running 15 volts on a 9 volt relay) but a few times it was in relays that were not abused. In these cases I assume it was either a design problem or a materials problem with the core material.
I've had good success at reversing this behavior by just swapping around the coil wires on the relay. Then I try to figure out why it got magnetized in the first place
One note regarding your original question about the relay sticking... a number of times during my years of playing with electronics, I've had relays start sticking. Most of the time it was because the core of the relay's electromagnet (or the reed "guts") became permanently magnetized making them inclined to stick. This can happen because you apply too much current (too much voltage) and the magnetic field becomes great enough to permanently alter the core and leave it magnetized; indeed, most of the times I've seen it happen were due to abuse (like running 15 volts on a 9 volt relay) but a few times it was in relays that were not abused. In these cases I assume it was either a design problem or a materials problem with the core material.
I've had good success at reversing this behavior by just swapping around the coil wires on the relay. Then I try to figure out why it got magnetized in the first place
u turned em,
You can buy them through mouser #551-PS2501-1. they replace the reed relay onthe MS20. only difference is you have to observe polarity when hooking up camera, which isn't hard, pos - pos and neg-common.
They are pretty cheap .42 cents but you kinda need to order $25 of stuff or they charge you a fee.
You can buy them through mouser #551-PS2501-1. they replace the reed relay onthe MS20. only difference is you have to observe polarity when hooking up camera, which isn't hard, pos - pos and neg-common.
They are pretty cheap .42 cents but you kinda need to order $25 of stuff or they charge you a fee.
ArkansasElkHunter
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Yea, what he said. I knew there was a led in there somewhere. Good explanation Arch.
About the Stinking, I mean sticking relay,
Magnets are created when things get all lined up inside the iron core and, like Jon said, an over-voltage on the coil can leave a residual magnetism that is strong enough to cause the relay to stick (when the voltage is removed from the coil)
Believe ir or not, Dropping or striking a permanent magnet can weaken the magnetism because things get jumbled inside the iron core instead of all being lined up, the more you strike it, the weaker it gets.
So......
Striking the sticking relay numerous times with a 2 pound hammer will definitly cause it not to stick anymore! ! ! ! ! !
Tinhorn
Magnets are created when things get all lined up inside the iron core and, like Jon said, an over-voltage on the coil can leave a residual magnetism that is strong enough to cause the relay to stick (when the voltage is removed from the coil)
Believe ir or not, Dropping or striking a permanent magnet can weaken the magnetism because things get jumbled inside the iron core instead of all being lined up, the more you strike it, the weaker it gets.
So......
Striking the sticking relay numerous times with a 2 pound hammer will definitly cause it not to stick anymore! ! ! ! ! !
Tinhorn
u turned em
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Arch....isn't it good to have good guys like AEH backing you up? AEH's reply gave me a good laugh! Both of you have been a big help to a lot of us novices and I sure admire AEH's methods of mounting his PIR and delay boards.
Arch., AEH, Davred1, Jon., and Tinhorn.......thanks so very much for the input. I swore I was not going to build another one due the the lay-off situation, but maybe I'll just tinker around with a new MS20 board ...uh....confession?.....uh....addiction?......uh...I just got back from WalMart with another one?.....uh....yes I did......uh....GUILTY! (but hey, I only paid $4.84 for it....they made a price mistake at checkout and gave me $3.00 back when I brought it to their attention.....their policy!).
Looks like I'm gonna give up RS relays and join the modern age of opto's. Can I get the optos. AND all the low power mod. parts from Mouser? Might as well go the whole distance on the mods.
Hmmm......wonder if I could wire an opto. to my 11 year old to get him jump started in the morning?..... i.e., I turn the lights on and he immediately gets ready for school....??
Arch., AEH, Davred1, Jon., and Tinhorn.......thanks so very much for the input. I swore I was not going to build another one due the the lay-off situation, but maybe I'll just tinker around with a new MS20 board ...uh....confession?.....uh....addiction?......uh...I just got back from WalMart with another one?.....uh....yes I did......uh....GUILTY! (but hey, I only paid $4.84 for it....they made a price mistake at checkout and gave me $3.00 back when I brought it to their attention.....their policy!).
Looks like I'm gonna give up RS relays and join the modern age of opto's. Can I get the optos. AND all the low power mod. parts from Mouser? Might as well go the whole distance on the mods.
Hmmm......wonder if I could wire an opto. to my 11 year old to get him jump started in the morning?..... i.e., I turn the lights on and he immediately gets ready for school....??
Take a Y shaped small limb from a Chinaberry Tree. Cut two strips of rubber from an old inner tube, tie strips of rubber to the stick. Tie on a pad made from an old leather shoe tongue. Place Relay in pad, pull back on pad while holding Y stick in other hand, turn loose of pad. This will Correct a defective Relay, especially if you shoot it off a steep mountain or over a big pond. hehe
Now put another Relay in it lol. bat
BTW, HEY Tinhorn haven't seen you lately!
Now put another Relay in it lol. bat
BTW, HEY Tinhorn haven't seen you lately!
