When Combat Robot Wheels Need To Be Nice And Cheap (But Mostly Cheap)

July 10, 2022 by Donald Papp 11 Comments

It started with [CHORL] making a promise to himself regarding constructing a new combat robot: no spending of money on the new robot.

That rule was violated (but only a little) by making his robot’s wheels out of EVA kneeling pads. EVA (Ethylene-Vinyl Acetate) is a closed-cell foam that makes for durable yoga mats, kneeling pads, and products of a similar nature. [CHORL] found a way to turn them into light but serviceable wheels for his robot: the Susquehanna Boxcar.

Nested hole saws create concentric holes. Perfect for wheels.

Here’s how the wheels were made: [CHORL] began with two hole saws. Nesting a smaller hole saw into a larger one by putting both on the same arbor created a saw with two holes, both of which were centered with respect to one another. The only problem was that this hole saw was not actually deep enough to cut completely through the thick foam. Luckily, cutting roughly halfway through on one side, then flipping the sheet over and cutting through from the other side was a good workaround. That took care of turning the thick foam sheet into round wheels.

A 3D-printed part served as a wheel hub as well as gear for the drivetrain. We want to call attention to the clever method of reinforcing the connection between the parts. [CHORL] didn’t want to just glue the geared hub directly to the surface of the foam wheel, because he suspected it might separate under stress. To address this, he designed six slots into the hub, cut matching slots into the foam wheel, and inserted six spline-like reinforcements in the form of some ABS strips he had on hand. Gluing it all together with E-6000 and leaving it to cure overnight under a weight resulted in a geared wheel assembly that [CHORL] judged to be about as round and rigid as a wheel should be, so the robot had a solution for nice light wheels that were, above all, cheap!

Lots of robots need wheels, and unsurprisingly, DIY solutions are common projects. [CHORL]’s approach here looks pretty scalable, as long as one can cut some accurate holes.

Interested in knowing more about the robot these wheels are destined for? [CHORL]’s still working on the Susquehanna Boxcar, but it’s almost done, and you can read a bit more about it (and see a few more pictures) here.

Inputs Of Interest: The Infogrip BAT Chording Keyboard

August 18, 2020 by Kristina Panos 29 Comments

I guess it shouldn’t surprise me that by researching weird and interesting keyboards, I would uncover more weird and interesting keyboards. This is the BAT personal keyboard by Infogrip, and it’s something I came across while researching the DataHand keyboard and mentally filed away as something cool to look into.

When I came across a used BAT for a reasonable price, I snagged it, even though it didn’t come with any of the manuals or software, not even a cord. Like I said, reasonable price. I looked these keyboards up and found out that you can buy them new for a lot more than what I paid.

My gently used BAT in all its angular glory.

The lowercase letter chords use either the middle thumb key or no thumb key. Image via Infogrip

So what is this thing? It’s a chording keyboard that’s meant to be used a standard PC input device by anyone who either can’t use a regular keyboard or has a need for speed. Years of research went into the BAT’s chording scheme, which was developed in conjunction with NASA’s Stennis Space Center.

Instead of stretching your fingers all over a regular keyboard, poking keys one at a time to spell out words, you press combinations of keys simultaneously, like playing chords on a piano.

You’re meant to use your thumb for the red, grey, and blue keys, and lay the other four on the rest of the keys. All of the alphabet keys are chorded with or without the gray thumb key, and all the number, symbol, and modifier keys are accessed through the red and blue layers.

Why would you want one of these? Well, given enough time to learn the chords, you can do anything a standard 104+ keyboard can do with only seven keys. You would never need to look down, not even for those weird seldom-used keys, and the only finger that ever travels is your thumb. All of this reduced hand/finger/wrist travel is going to be easier on the body.

The BAT lets you CAD like a madlad. Via Bill Buxton

The BAT is also part programmable macro pad, and from what I can gather, the main selling point was that you could quickly input shortcuts in CAD programs and the like, because you could keep one hand on the mouse.

The BAT came in both left- and right-handed versions that can be used either alone or together. Imagine how fast you could type if you chorded everything and split the typing duties between both hands! The only trouble is learning all those different finger combinations, although they say it doesn’t take that long.

So why is it called the BAT? Legend has it that it’s because company started out in Baton Rouge, Louisiana, but also because a pair of BATs sitting next to each other resembles a bat (PDF).

Continue reading “Inputs Of Interest: The Infogrip BAT Chording Keyboard” →

Crafternoon: Forget Potatoes, We’re Making Stamps With Lasers

March 22, 2014 by Kristina Panos 18 Comments

No, that’s not Heisenberg without his hat. It’s [Jens], and he laser-cut a stamp of his face out of EVA foam. He made the laser cutter himself, which we covered a couple of months ago.

Let’s take a brief interlude to discuss your beautiful eyeballs. Keep them safe, okay? If you’re going to play with lasers, be smart and protect yourself according to the wattage and wavelength. Alright, back to business.

[Jens] started by making a stencil from a photo using this tutorial. He added a frame and supports around his face to keep everything where it should be. [Jens] then turned to Inkscape to generate the g-code using the laser plugin and then proceeded to cut his countenance into EVA foam.

After gluing the foam to a wood backing, he cut off the supports. Now it’s ready to stamp. You could use a brayer if you have one or maybe your wife’s rolling pin to apply whatever ink or paint you want to use. [Jens] loaded up his stamp with a sponge.