I am wanting to electronically detect if a pest trap has been triggered. It does'tn have to be detected in real time, it can be done periodically. ( ie, check once every x hours ).. I'm wondering what kind of sensor system might be useful for this.
Its got to be low powered as well.. ( needs to run off batterys.. ). I'll have a low power microprocessor and radio to process the message..
Anyone got some great ideas.
That thing is going to make a seriously loud noise when it trips, so how about a microphone?
Dedicated "mute" ICs used to be available which were used in radios, so if you can get one which just presents a logic level change at its output, you are halfway there.
If you have to fart around setting levels & stuff with a PIC or whatever, it is a bit more messy, but still do-able.
Those are usually fixed in a box/tunnel - why not just use a waterproof microswitch or a car interior light door switch (with rubber boot), mounted on the side of the box & held operated by the hammer when set, as the sensor?
Is the trap for kangaroos ? Never seen it before.
Seems a micro switch would work.
simple pulse light sensor working on reflection from the part when it off. of course this parts shouldn't be there when armed.
Option 2, a hair like coil wire torn when it moving.
Radio? VHF/UHF/WIFI?
Lots of information out there for go/no-go signalling with the ESP8266 (WIFI)..they're pretty cool!
Just got a pile of RCWL0516 sensors in..
THEY are some nifty & cheap units!!! Use a logic level latch for trigger indication, as the reset is just a few seconds.
Might want to check the RF/Ham radio forum/section (or ARRL handbook ) for more VHF/UHF signalling questions?
..perhaps "strike anywhere" matches attached to the trip/bail....when you see smoke in the woods!!!.. (joking!)
Edit: More interesting stuff here;
http://andicelabs.com/2013/07/the-tale-of-a-rat-zapper-part-2/
As EZ said, use a simple micro switch. When the trap is set, the switch interrupts the power to the micro, then when the trap is triggered the power comes on and your software controls the time on and off as you wish to broadcast. Use the frame to mount the switch.
Huge trap!
What are you catching? Possums or stoats?
Place a microphone to catch the cries of the animal when it has the paw broken by the trap ...
It's cruelty to animals ... Permitted in Australia?
Huge trap!
What are you catching? Possums or stoats?
Stoats, Rats.. mostly.. Yes, these are normally set up in a 'tunnel' so that non target species ( domestic cats mostly ) or birdlife ( which is why we are trapping ) can't get in.
For possums we use somethign similar in operation, called a tims trap. Quite a bit bigger set up though.
Place a microphone to catch the cries of the animal when it has the paw broken by the trap ...
It's cruelty to animals ... Permitted in Australia?
Pretty sure the OP is Kiwi.
Similar flags but different tastes in livestock to us Aussies.
The traps have been tested and approved to be humane. A stoat is dead before it knows what has happend. Its instant.
It's sort of too bad the trap is all metal, if you got the right mix of materials used in the base and support structure, you could just wire a sense line on the trigger and the arm and when the sense line goes open, your trap is sprung.
That thing is going to make a seriously loud noise when it trips, so how about a microphone?
Dedicated "mute" ICs used to be available which were used in radios, so if you can get one which just presents a logic level change at its output, you are halfway there.
If you have to fart around setting levels & stuff with a PIC or whatever, it is a bit more messy, but still do-able.
This is very true. And this gives me an idea. When they go off, they really do go off. Its a very strong spring and it really accelerates very fast. When it hits the base, it really hits. At least for the said 'victim' the end is quick.
A peizeo electric transducer would certainly pick up the hit.
The problem i have with microswitches ( which would be the easiest way by a long time ) is that these traps are in ugly places, with mud, and rain. A peizo could be sealed up and attached to the side of the box.
The traps have been tested and approved to be humane. A stoat is dead before it knows what has happend. Its instant.
Sounds like stoat is something you order when you go to a bar, "hey bartender, give me a tall cold stoat".
https://en.wikipedia.org/wiki/Stoat
"What is the difference between a Stoat & a Weasel?"
"A Weasel is weasely distinguished, as a Stoat is stoatally different!"
Place a microphone to catch the cries of the animal when it has the paw broken by the trap ...
It's cruelty to animals ... Permitted in Australia?
When set up properly, in the box with baffles & all, they're (a) pretty impervious to larger animals sticking a random paw in & getting it smooshed, and (b) fairly humane in that they're designed to kill animals of the target size instantly.
Here's a NZ DoC brochure showing the usual setup. (pdf)
The problem i have with microswitches ( which would be the easiest way by a long time ) is that these traps are in ugly places, with mud, and rain. A peizo could be sealed up and attached to the side of the box.
FWIW I've seen car interior light switches used on live cage traps to trigger a transmitter in cases where you don't want the animal to be trapped & vulnerable for too long (e.g. where there lots of predators, like dingoes, that can trash a small trap). They're pretty well sealed to start with, and a bit of silicone sealant or 'blackshit' (self amalgamating tape) works well enough on the terminals / connectors / entry holes. No problems in coastal Australian bush/forests/swamps, though admittedly it's probably drier than most NZ bushland.
firstly thought about a button used on the 3D printer... or IR detector to detect the trap location(trapped or not):
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FWIW I've seen car interior light switches used on live cage traps to trigger a transmitter in cases where you don't want the animal to be trapped & vulnerable for too lon
The animal is well dead almost instantly. the reason for the notification is so you can go and reset the trap, to catch the next one.
Place a microphone to catch the cries of the animal when it has the paw broken by the trap ...
... Permitted in Australia?
And that right there is an example of why we shoulda changed the flag....
That thing is going to make a seriously loud noise when it trips, so how about a microphone?
Dedicated "mute" ICs used to be available which were used in radios, so if you can get one which just presents a logic level change at its output, you are halfway there.
If you have to fart around setting levels & stuff with a PIC or whatever, it is a bit more messy, but still do-able.
This is very true. And this gives me an idea. When they go off, they really do go off. Its a very strong spring and it really accelerates very fast. When it hits the base, it really hits. At least for the said 'victim' the end is quick.
A peizeo electric transducer would certainly pick up the hit.
The problem i have with microswitches ( which would be the easiest way by a long time ) is that these traps are in ugly places, with mud, and rain. A peizo could be sealed up and attached to the side of the box.
Why not stick with the agricultural mindset and have a small transmitter that is enabled when its switched on, the trick being that switch is one that is turned on by pulling a pin (pin flag switch style) out of it with a string attached to the closing jaw. There are ways to get enough travel/leverage on the trap its self and make a solution which doesnt require any constraints on the placement within a box/tree trunk/etc. Or if you're concerned about the weatherproofness of typical limit switches there are Automotive switches for checking if doors/bonnets/hatches are open that are available and some of those might fit the required shape already, held open by the jaw until it closes then enabling the transmitter.
Probably the simplest and most robust solution is a vibration sensor switch like this:
https://www.adafruit.com/product/2384There are a few variations on this; a spring around a rod, a ball or rod rolling amongst multiple contacts. Set up a pin change interrupt to wake up a sleeping microcontroller or trigger a comparator, super low standby current. Plenty of examples once you get the right search phrase.
They are very cheap on ebay and you can encapsulate them as needed for conditions. If you epoxied one to the base of that trap it would trigger for sure, it would not need to go on the killer arm.
I use one with a Moteino to protect a wildlife camera. Works great.
After reading the docs on the trap, my guess is a sound solution is best. I think you could come up with a small box that could be placed near the trap therefore no work would have to be done on the trap.
Probably the simplest and most robust solution is a vibration sensor switch like this:
https://www.adafruit.com/product/2384
There are a few variations on this; a spring around a rod, a ball or rod rolling amongst multiple contacts. Set up a pin change interrupt to wake up a sleeping microcontroller or trigger a comparator, super low standby current. Plenty of examples once you get the right search phrase.
They are very cheap on ebay and you can encapsulate them as needed for conditions. If you epoxied one to the base of that trap it would trigger for sure, it would not need to go on the killer arm.
I use one with a Moteino to protect a wildlife camera. Works great.
Thats a great idea. I'm goign to give this one a try. thats really simple. and i suspect it will work nicely.