DIY Mouse

December 13, 2005 12:57 PM

DIY Mouse. I want to make a mouse, where should I start? How does one go about getting custom plastics molded? Should I use CAD?

This will be for ergonomic reasons as well as wanting to undertake a usefull DIY project. I have some good ideas (to me) and would like to fabricate some for myself, but also for freinds and relatives who are gamers/avid computer users.

posted by parallax7d to computers & internet (18 comments total)

Why make it out of plastic?

Go to your local computer store and get the cheapest optical mouse you can find. Take it apart, saving the cord, the electronics, the optical sensor, and the button switches.

Now get a block of pine or balsa and carve it down to the shape you want. Implant the electronics and buttons into the wood mouse body. Paint it with acrylic paint if you want it to have a plastic feel.
posted by b1tr0t at 1:06 PM on December 13, 2005

Watching industrial design majors when I was in college, I would say your early steps is to shape some models of the mouse in clay and/or wood -- fine tuning the shape and all that. Basswood is a good wood to carve for this purpose.

On preview, if you are going to make a final mouse of wood, you will want to make it with something like pear wood -- balsa and pine will not work for a final copy.
posted by Dick Paris at 1:09 PM on December 13, 2005

As above, but substitute the wood for a huge mass of play-doh. Ergonomic!
posted by fire&wings at 1:09 PM on December 13, 2005

what a cool idea. it sounds like you are going with a one-off design, so my recommendations would be to

custom form a top by casting your hand in the exact grip you want the right shape then do a vacuum form of that grip. Vacuum forming plastics is easy and cheap, and you can do it with a variety of thicknesses and types of plastics (my experience is mostly with 1/16 and 1/8" PET). It's easy and cheap, so you should also be able to cut buttons out of it by making several molds that can be sliced for making the different parts.

limit CAD use: it is an awesome tool, but maybe more for mass-manufacture work. What I see it being useful for here is if you were to custom-mold a top part (the part you grip) but then needed to cut (laser-cut, probably) a bottom to match it. Then you may have to worry about CorelDraw (which "prints" to laser cutters), G-code (speaks to CNC machines, but I think those will be less relavent to what you're looking to do), or water-jet cutters (awesome, but overkill)

I don't know anything about the electronics, but like the above idea of cutting them from an existing mouse. If you have any more questions about the plastic forming, let me know. I also might be able to help get the actual forms or cutting done ifyou choose that route.
posted by whatzit at 1:12 PM on December 13, 2005

mm. clay to plaster to vacuum form would also be good. undried clay by itself would just smoosh, and the shape would forever be lost. oven-baked clay like sculpey may be appropriate for vacuum-forming, but i haven't tried it.
posted by whatzit at 1:18 PM on December 13, 2005

I've used plain plastercine stuck onto a mouse that was too small. Shaped to fit my hand. After a few days the plastercine hardens up. The only real problem I experienced was the plastercine required careful cleaning instead of just wiping with a cloth.
posted by Mitheral at 1:42 PM on December 13, 2005

"Thermoplastics can all be shaped and formed by immersing in hot water (160°-180° ) until soft and pliable, then applying to a mold or form. Dry heat (usually in the form of a heatgun or hair dryer) can also be used for the initial forming or later to build up areas or to reshape. The material can also be sculpted freehand without a mold."
posted by Laen at 1:44 PM on December 13, 2005

Consider an even simpler way of forming plastic than vacuum-forming. Once you make your mold (positive shape form out of hardened clay, wood, urethane foam...) heat some sheet plastic up with a heat gun (carefully) and use some thick, heat resistant gloves to push the soft sheet over the form until it cools. It may take a few heat/molding cycles to get it right. Then trim off the extra plastic and you're done. Certainly not as good as vacuum forming but it works ok. This is the way some prosthetists mold plastic for the cavity of a prosthetic arm. It allows more control over how the plastic drapes over the mold - more importantly to hobbyists, it doesn't require a vacuum or hardly any other equipment. Of course, check out makezine .com for other tips for makers.
posted by spirograph at 1:53 PM on December 13, 2005

Don't just canabalize the circuit, cut away and reuse the entire bottom surface of a factory mouse.
posted by Chuckles at 2:28 PM on December 13, 2005

There are a lot of places that will custom-mold plastic for you, but it's expensive. I wonder if emachineshop.com would do something like this...
posted by jewzilla at 4:50 PM on December 13, 2005

You should also look into liquid resin casting, a method for cheaply "mass producing" plastic components in small quantities.
posted by ZenMasterThis at 7:33 PM on December 13, 2005

(small quantities = less than 500 pcs)
posted by ZenMasterThis at 7:34 PM on December 13, 2005

If you have access to a 3d modelling program, there are outfits who will "print" your model directly from the electronic file. Google for "rapid prototyping", "3d printing", "stereolithography", "fused deposition, "selective laser sintering", or even "cnc milling" + your town.

The piece will be made of metal, plastic, plaster or wax depending on the process. Price can be an issue though - usually more than $5 / cubic inch.
posted by Popular Ethics at 7:58 PM on December 13, 2005

My question about the stereolithography approach is strength. What structural properties are possible...

Also, how are cubic inches measured in this context, if it is displaced volume it isn't too bad, but if it is the product of the three largest dimensions then you are talking a lot of bucks.

Err.. The question of how to measure volume may not be clear yet...

1. The volume of a 1" diameter hemisphere is pi/12 cubic inches.
2. The volume of a 1" diameter hemispherical shell is approximately pi*thickness/2 square inches.
3. The product of the three largest dimensions is 0.5 square inches.

posted by Chuckles at 8:16 PM on December 13, 2005

err, replace those two last "squre inches" with "cubic inches"... DOH!
posted by Chuckles at 8:17 PM on December 13, 2005

Here's a comparison of material properties for various 3D printing processes.

• Z-Corp machines use plaster, which is brittle unless it's but through a binding process with epoxy.
• Fused deposition uses ABS, which your current mouse is probably made from.
• CNC machining can use any material really.

Here's a quick Google result for 3d printing cost. The price / volume of 3d printing usually refers to the finished part, since unused material (photoset plastic for stereolithography, ABS beads for fused deposition, starch powder for z-corp machines) can be recovered.
posted by Popular Ethics at 9:23 PM on December 13, 2005

That's awesome Popular Ethics! Thanks!

I was beginning to think my question about how volume is measured was kind of dumb, but I see that the U of A people charge a pretty steep penalty for height. Yes, it makes perfect sense that it should be charged that way when you think about it... Overall, extraordinarily inexpensive, at least for mouse sized parts or smaller.
posted by Chuckles at 12:29 AM on December 14, 2005

Wow, thanks for the awesome responses folks, I wish I could mark you all "best answer". Well I suppose I could, but I don't feel like clicking that much with my non-custom mouse. Maybe once I make the new one I will come back and do it.
posted by parallax7d at 5:13 PM on December 14, 2005