Mechanical challenge - falling gate with lock

Hi all

I have earlier tried this forum with success on serious off-topic challenges. I want to try again… :slight_smile:

I am trying to build a remote-controlled trap for smaller animals. The law says that traps should be looked after every 12 hours. In case the trap is not looked after, it should automatically open.

I want a mechanism for a prototype based on standard available components to be able to open the gate. Image of the trap is attached.

Normally when the gate falls down, there is a lock that falls into place, this lock should be replaced with another mechanism that can keep that animal from pushing the gate up again.

I have a few working prototypes, but none of my ideas has been stable and able to handle snow, leaves and nature in general. :wall:

All ideas, experience welcome!!!

EDIT: If anyone has links to relevant forums, I would love to hear from you!

String on a spool should be able to cope with the existing door and lock mechanism?

What if the top hinge of the door were held in place with an electromagnet or other servo actuated clasp. Then when the 12 hrs expires you simply let the door fall down. The main risk would be if the animal is under the door and doesn’t figure out how to escape. But, if you’ve opened the door then I’d say you did your part. The nice part about using an electromagnet solution is that if the battery dies then the door would automatically open also.

@ njbuch - In your prototypes is it the mechanics that cases problems with snow or the electronics?

I am not sure how to realize this, as the string needs to be “freewheeling” when gate falls, but able to pull up the gate when openening. I need a kind of two-state-engine for this…?

I am not sure I understand you right, but I have had the gate hanging from a permanent electromagnet, which was nice. And then when the trap triggered, the magnet release the gate. That part was fine.

But the challenge is opening the gate, when is in the low position…

The snow is a primary concern for the mechanics, proper casings should be possible for the rest.

@ njbuch - I will talk to a friend of my who made a number of this type of caves when he studied and did research in the Amazone of Brazil… I get back to you if he has some ideas

Awesome! Thanks a lot!

I mean to use an electromagnet for the HINGE not the triggering mechanism. Like this. So, when the hinge is released the entire door will then lay flat at the bottom of the cage.

Ahh, I understand. A kind of emergency “the gate will fall off if you dont look after it”. Interesting idea. The most optimal solution is to make the trap ready for next catch…

I thought the optimal solution was that you would actually check the trap every 12 hours :wink: There probably wouldn’t be any bait left at that point anyway. As far as reloading, I don’t have any good ideas short of complicated gearing solutions that would be subject to failure due to leaves, sticks, etc. I’ll keep thinking… One thing that does come to mind is an automatic mouse trap that I own. It doesn’t automatically release but it does automatically reset after a mouse is caught. Its a different problem when you’re talking about larger animals, though.

How about using a simple sand capsule glass that can tilt when the trap in on and start pouring the sand the other way until the other side is full which would be heavy enough to open the gate and tilt the capsule again and resets… to get 12 hours you would calculate how much sand you would allow to flow from one direction to the other per minute…
Think of the pyramids and secrete doors.

You still have to figure out how and where to place it :slight_smile:
No electronics pure mechanical timer :whistle:

Hope this helps.

Small or big, same mechanics might apply. Do you have the trap? picture?

Creative idea! Not sure it ends up cheaper, or easier. Will think about it!

This is the closest thing I could find. I bought mine about 10 years ago. So, they may not make them anymore. I haven’t used it in a while but I believe mine winds up instead of requiring batteries. It may not scale well for larger, heavier animals.