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Bird House Geocache with a Twist Answered

Hello everyone! I am interested in creating a geocache for an upcoming event I will be attending. My thought is to have a birdhouse (fairly large) that will have walls that are on hinges that open when the person presses down on a plunger of a dynamite box (handmade of course). Crazy idea I know but I am basing it on the event. While I have limited electronic knowledge I am in dire need of help in trying how to make this work and have it be able to reset itself for the next person to find.I would greatly appreciate any help with how this would work, and would definitely give credit to anyone who helps in the cache listing. Thanks in advance.


Are you wanting this to be wireless? Where are you going to place this cache where people are not going to freak out because they see a dynamite plunger.

For a geocache i would suggest not making this electronic in any way. Otherwise you run into problems with the electronics failing do to exposure to the elements and having to maintain the cache more often to replace batteries.

I suggest you simplify this a bit. Only make one side of the bird house open. Use a kinematic system to release the catch on the door. One that is spring loaded so that the plunger brings itself back up and the catch re-engages after the door is opened. Then the cacher only has to close the single door when they are done.

If that sounds too complicated for you then any electronic means with your limited knowledge will be far more complicated. If you want it wireless you get kits what have a wireless key fob remote and a receiver. The receiver can be connected to a micro controller that will activate an electronic cylinder or servo to allow the doors to open. If you use a servo then you may need to have a reset button for the cacher to press once the door is shut so it will lock again.

Overall i see too many problems which will lead to cacher neglect and many headaches for you maintaining such a cache.

I appreciate the information you have given me. And as I am limited in my electronic knowledge, I still want to make an attempt to create something that hasn't been done before and something I can be proud of. I'm looking to impress the finders, and if they're like me they are tired of finding simple tupperware.
Lets assume I only have one side the bird house open, where can I learn about the kinematic system?

Also, I would be getting permission for the placement of this cache in an area that is known for one of a kind caches, so hopefully a TNT box wouldn't scare very many people. And, it doesn't need to be wireless I can just run a cable from the birdhouse to the plunger.

If you have done a similar project or know of any I would love it if you could point me in the right direction in getting this off the ground.


I envision the plunger like the plunger of a large plastic syringe. So that when it's pressed down it sends a volume of air through the tube to a small plunger which will lock and unlock the door. The plunger can be another smaller plastic syringe which can push the release of a small spring loaded latch. Thus unlocking the door allowing it to pop open. A spring loaded hing on the door will help to pop it open. Then the catcher can close the door and pull the syringe back out to lock it again.

Now the air temp can cause trouble with this type of system. If you super glue the hose to the syringes you can use a liquid that won't freeze to make things a bit more reliably. It's a concept you can play around with anyway. As you can see the parts to make this work won't cost much. So if it doesn't work out your not out a lot of money like you could be with an electronic system.