Category: MakerBlock

All things MakerBlock: RepRap, MakerBot, Cupcake CNC, open source, and plastic building toys!

RepRap interim challenge obstacles

The RepRap challenge has a number of obstacles for the interim award.  There are two in particular that seem insurmountable.

  1. Maintain a total materials and parts cost under $200 and that 90% of the volume of the printer parts be printed.
  2. The ability to print autonomously without a PC attached.

I have to imagine something large enough to accomplish all of the other goals would cost well over $200.00.  If an entire Darwin or Mendel were trasmorgrified King Midas1 style into pure plastic, I would think the plastic alone would eat up 90% of the budget.  Even the best deals around the internet for RepRap parts just the electronics are roughly $215.

I say it seems insurmountable – but if someone had told me two years ago I could one day buy a full kit for building a robot that would make me any plastic thing I could imagine for $1,000.00  I would have laughed at them.

  1. or Calvin and Hobbes [↩]

Wait a second… that’s not a trap at all!

I just realized that the second variation of my funnel/one-way-door mousetrap doesn’t really trap mice at all!

Since it is specifically designed to provide an avenue of escape to the mouse, there’s no trapping being done, and I may have just miserably failed the design challenge.  The challenge specifically states that the winning design is the one that first catches his mouse.

Plus, this particular design would require you to drill a 4cm hole and 4x 3mm holes in a door.  I’m guessing this is one of those “cure is worse than the disease” solutions.

How to test a ridiculous idea

Cathal Garvey posted his recommendations as to how those without mice can test their designs.  He suggests:

*Think* like the mouse, *be* the mouse!
Alternatively, leave one outside in the country or garden, and await your furry, diseased reward!

But how do you test a one way door/mouse funnel mousetrap if you don’t want to invite mice into your house?  I suppose a box with two such funnels installed with a bit of peanut butter inside.  If you wake up and find no mice or peanut butter – it either worked perfectly1 or it failed miserably2 !  If the mouse is stuck inside…  well I guess it kinda succeeded.

  1. as in the mouse left via the second one-way-exit [↩]
  2. as in the mouse left the wrong way out the first one-way-exit, just to be a rodent jerk [↩]

Must… stop… brain…

I can’t help it.  Another idea using the last mouse funnel occurred to me.

What if you had a long tube with a series of bristles all pointing in the same direction just like the mouse funnel?  Put some peanut butter on the outside, install in a door, and walk away happy and content that you’re saving mouse lives.

Once the mouse started down that tube it wouldn’t be able to turn around or back up easily.  Given the option of unlimited freedom outdoors and chewing its way back through pokey bits, I can’t imagine it would choose plastic splinters.

Self-emptying mouse funnel mousetrap

I’ve spent WAAAAY too much time thinking about this problem.  Here’s my new idea:

The hope is that a mouse inside your house will walk out the hole in the door to get to the peanut butter on the other side of the funnel.  Once inside the box with all of the peanut butter consumed the mouse can either (a) try to struggle past the pointy bits back into the house or (b) slip outside through the second funnel.

Mouse funnel mousetrap

Peanut Butter Jar Mousetrap v2.0
Mouse funnel mousetrap

After thinking a bit more about my design for a Peanut Butter Jar Mousetrap, I decided it could be even more minimal/adaptable.

This new mouse funnel mousetrap design requires four bolts, four nuts, and some kind of container with a 4cm hole in it.

Peanut butter is still a really good idea.

Peanut Butter Mousetrap design notes

I treat this blog as part of my lab notebook on printing and designs to help keep me organized.  Having it automatically add tags, adding a time stamp, organizing everything in chronological order, and then making it available for others to learn and comment back are all just a huge bonuses.

Anyhow, here are some of my design notes for this Peanut Butter Mousetrap Insert:

  1. I was going for a minimal design – minimal plastic, printing, and machine time.
  2. I wanted something that would be “ABS warp” resistant.  Even if you end up with a warped flat surface, clamping the insert between the lid and the jar should even it out.
  3. I wanted a resilient design.  Even if the insert is badly warped after clamping down, a flat surface is not critical to its function and it should still work.
  4. I wanted something that could be adapted easily.  I don’t know how to use OpenSCAD, so a parametric design is kinda out the window.  Even so you could print this object at full size and then cut it down to what you need.  1
  1. For the record, I did download OpenSCAD before designing this.  I just wanted to get it out there. [↩]
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