Wednesday, May 28, 2014

DIY CNC plasma cutter (in progress)

This is my DIY CNC plasma cutter. It is 100% built from recycled parts. The total cost to build (with the exception of the plasma torch, is < $200. It is very much a work in progress. I am working to reduce backlash, and improve precision. I have only just recently attached the plasma torch, and just need to wire up a controller for turning the torch on/off. I am planning to use a waterless grill for V1. I am also looking at upgrading the linear rail system to one based on openrail, for more accuracy.

Friday, May 23, 2014

The closest thing to a real lightsaber

This incredible project fulfills a childhood dream... I always wanted a real lightsaber. I have made several in the past, but those didn't cut through thick steel like the Jedi's do. I decided it was high time, I remedied this problem. I found a bunch of scrap parts, and turned the hilt on a lathe. I then bought a CNC torch head for a plasma cutter, and modified it to fit inside of my hilt. Watch it cut through steel like... well, a lightsaber.

Thursday, April 10, 2014

The perfect coffee maker

TL;DR: This thing makes amazing bitter-less coffee, cost only $150, and was built in one weekday evening.

This contraption is known as an Oji slow drip cold brew coffee system.
You fill the top with ice, and a bit of water.
You fill the center with coarsely ground coffee, and a glass filter disk.

You set it so the top container drips 1 drop of water per second, and the second container so that it drips 1 drop of water per two seconds.
This allows a pool of water to form in the middle beaker, maximizing extraction surface area.

Because you use ice instead of hot water, far less tannins and oils are extracted from the coffee. It also takes 10 times as long to extract the caffeine and coffee flavors out of the ground coffee beans; this is why the brewing process takes roughly 8 hours.

There are lids/filters on each beaker to prevent dust/hidden nasties from contaminating the brew during the 8 hours it takes to brew the coffee.

8 hours may seem like a long time, but if you start it before going to bed, its ready when your ready to drink coffee. Another cool aspect of cold brew is that it doesn't go stale (unless you heat it, at which point it will go stale if you don't drink it).

Because the coffee doesn't go stale you can supposedly age it and develop the flavors even further.

About the build: These setups normally cost at least $500 for a 12 cup system. I pulled this off for $150. I purchased the replacement parts from Yama (the beakers are uniquely suited for the task of brewing up to 12 cups of coffee). I purchased the glass filter (just wash, never needs to be replaced). I already had the carafe. Not pictured are the stopcocks for the top and middle beakers which are just glass valves for precisely adjusting the flow. I bought them on ebay for $20 each. I am still waiting for them to arrive so I rigged some vinyl tape stopcocks for the first brew.

I drew the design in cad, laser cut templates, and cut it out on a scroll saw. I sanded, primed, stained, lacquered, oiled, glued, and mounted in a few hours last night. 

Success metric:
  It needs to be as practical as a normal coffee maker in terms of cleaning, ease of use
  It needs to produce a noticeably better coffee than a coffee press.

The coffee is amazing. I am not a coffee snob. The purpose of building this was for the fun of building it. I expected to not be able to notice any difference in taste compared to other coffee makers being a non-coffee aficionado... I was super wrong. There is almost no bitterness. It is pleasant to drink black (I am a creamer guy). Everyone who has tasted it agrees unanimously it exceeds expectations in terms of taste (my wife was pretty skeptical about this project).





Tuesday, April 1, 2014

Exoskeleton for the girl with a broken ankle

My sister broke her ankle rock climbing. The crutches were annoying her and I thought I could come up with an engineering solution to the problem.




The straps are laser cut acrylic. I thermoformed them to the shape of her leg. On the inside of the straps is non-slip foam padding, and on the outside is industrial strength velcro.

The hinges have bearings in them. The general idea is you slip your leg in, wrap velcro around the straps, and your ankle hovers a few inches above the ground. A shoe riser goes on the other foot, and you walk with a cane.

The device worked as intended, but proved to be cumbersome to wear for long periods of time. It is also still easier to get around on crutches. The upside is, it did allow her to walk for short periods of time without crutches. This was version Mk I. We did three iterations before moving on to other projects

Thursday, March 27, 2014

Highly detailed wood inlays

 I had an unscripted maker day recently. The day consisted of making various random things. These are some of the wood inlays we created on my laser cutter. They turned out pretty awesome! We also did a bunch of welding, wood working, etc. But I wanted to show off some of the cool laser cut projects.



Saturday, November 16, 2013

Exploring EMG controlled prosthetics limbs

I apologize for the lack of information in advance. This is actually an old project, which I am posting at a later date.

Tim Courrejou, and I got together with the goal of exploring the new at the time EMG arduino shield for measuring electrical activity in nerves. I spent about a week printing out the inMoov roboting arm on my 3d printer, and we spent a weekend playing with the EMG shield to see how feasible it would be to control a prosthetic arm using the shield. We modified the arm so the servos were on the outside, to allow room for a wrist inside of the robotic arm.

We were surprised with the level of accuracy of the EMG shield. We were able to isolate individual finger movements, tell the degree to which the finger was retracted, and tell whether the finger was holding in a close position, or relaxed.

We were able to graph the output from the shield. We determined that we would need a lot of the shields to power all 5 fingers, and your arm would be covered in sensors. In the end it wasn't practical to use off the shelf equipment to power the prosthetic arms, however one could be made with enough effort, and a much smaller foot print would be achievable.

Wednesday, September 11, 2013

Open gantry update

We have been working for some time to get approval from Google to release the files for the completed open gantry. It looks like that should be done soon, and that we will be able to release open gantry to the world. Here are some updated photos. The CNC is completely operational and cutting wood and cardboard. This is out 1:4 scale model. The total cost of this version came in at roughly $350. We have done the research and it looks like the full scale 9ft X 5ft version will cost $450 excluding the cost of router bits. The next steps for us is to organize the source files, create a bill of materials, write detailed assembly instructions, and get the word out.

We would love to work with some Alpha testers. We will provide detailed instructions and guidance for cutting and assembling the CNC. Anything and everything we can do to help we will. If you want a large CNC for ~$350-450 this is a great option.