catching Earl

How to catch a monster


Sometimes monsters are so shy/wild that you cannot pet them.

And also, Bodil doesn´t like them running around free, in our garage....
Especially not "Earl".


So we had to make a monster-trap in order to fix that problem,
But our first stone-age trap was not a success


Then, our next "tube trap" was awesome!

This the complete trap, under construction in the lab.
On top you can see the 5V power supply.
The idea is, that Earl will walk into the tube to check if there is any cheese. When coming close to the end of the tube, his weight will trigger a mechanism that releases the door. The door falls down before he can run back.

This is the mechanism that activates the trap; the spring is cut down, so a weight of 100 grams in the end of the tube will trigger the switch. The switch starts a motor that releases the falling door.
Why 100 grams? Well, we weighted Ikaros, and he was 47 grams. Then we multiplied by 2.12, which is our estimated multiplying factor for the size of Earl.

The motor that releases the door, is in fact a CD drive. When powered, it will pull to the left side. There the carriage stops when it activates the end-switch. (a relay does the job)

Did we catch Earl?

day1: Not yet. He has found the tracks to the tube, but didn´t dare to enter it yet.

day2: The trap is released!!!
But when looking in, it looks like nobody is there.....

Cheese and sunflower-seeds are gone; only a pile of shit..

That means, Earl could lift a door that weights 180 grams!
Man, he is not far from world dominion!

New invention to keep the door locked when released and down: spring-clamps.

This is how it looks when the door is locked; even 1000 grams brute force cannot open it.


Let´s see if he dares to enter the tube of doom again....

.....after one week
Earl still avoids the trap....

We dismantle it.


So we have to build another sort of trap, that Earl cannot figure out;

The "psychic bridge of doom" emanated from that:
Here the thing is installed in the garage:

On the inside is the bridge, where you can place some cheese and sunflower seed.

This bridge is designed with a mechanism that can break it

Breaking mechanism

The bridge is released by a CD drive, that pulls the steel wire.
The circuit that controls the motor, is triggered by a switch.
A spring and adjustment screw is used to control the triggering weight of the monster.

The trigger switch is on the outside, actuated by two pins protruding through the wall. The bridge is laying on those pins, on the inside.

So what will happen when Earl enters the trap to check for cheese?.
Here a demo with the car "Earl-buster".

First thing, when the weigth of the monster triggers the switch, is that the door closes.
This is done by another (vertical) CD drive.

Earl realizes that something is wrong, and wants to jump before the bridge falls.
But there two evil green cat-eyes are switched on.

All this psychic confusion is delaying Earl´s brain for 42 milliseconds.
So he will be caught, because the other CD drive has released the breaking bridge...

The psychic stuff is needed because the "breaking mechanism" of the bridge needs a lot of pulling force from the poor CD drive motor when a 100grams monster like Earl is situated exactly at the breakpoint of the bridge. That is solved by having him moving around, while the "hold-on relay" keeps the trap triggered.
Here the schematics.


.................


Few weeks later..... Earl is sometimes in the garage, sometimes in the woodpile, sometimes under the stairs.
He even made an emergency-exit in the woodpile, so he could flee from the neighbours cat.

But the trap?.. He only goes so far on the bridge that he can eat half of the bait and doesnt trigger the doom...


When we changed the breaking point of the bridge, he even figured that out...


> At this point, Bodil notified the authorities about Earl, and they set up some destructive traps and told us to block the door and window.

With Earl in the garage with no food but the traps, he would either be caught, or attack the first person opening the door...



But of course this was no problem for this endangered species.
He triggered the destructive trap without getting caught, ate the nutella in that trap, triggered the bridge-trap without being caught,
and finally moved a stone and escaped.



But he didn´t get the hint and kept coming back.
Even engineered a new motorway..


And that was not clever....
Poor Earl..

....tears.............