A Different Kind of Plastic Shredder for 3D Filament Making

Haven’t you heard? You can make your own 3D filament nowadays from plastic granules (10X cheaper than filament), or even by recycling old plastic! Except if you’re recycling plastic you will have to shred it first…

[David Watkins] came up with a different way of shredding plastic. Typically we’ve seen shrunken versions of giant metal shredders used to dice up plastic into granules that can be melted down and then extruded back into filament. These work with a series of sharp toothed gears that kind of look like a stack of circular saw blades put together inside of a housing.

But that can be rather pricey. [David’s] method is super cheap, and you can do it at home with minimal tools, and maybe $10 or less worth of parts?

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Astoundingly Great $60 3D Printer called Chimera Bests Your Printer

When most people think of 3D printing, they think of Fused Deposition Modelling (FDM) printers. These work by heating a material, squirting it out a nozzle that moves around, and letting it cool. By moving the nozzle around in the right patterns while extruding material out the end, you get a part. You’ve probably seen one of the many, many, many FDM printers out there.

Stereolithography printing (SLA) is a different technique which uses UV light to harden a liquid resin. The Chimera printer uses this technique, and aims to do it on the cheap by using recycled parts.

First up is the UV light source. DLP projectors kick out a good amount of UV, and accept standard video inputs. The Mitsubishi XD221u can be had for about $50 off eBay. Some modifications are needed to get the focus distance set correctly, but with that complete the X and Y axes are taken care of.

For the Z axis, the build platform needs to move. This was accomplished with a stepper motor salvaged from a disk drive. An Arduino drives the motor to ensure it moves at the right rate.

Creation Workshop was chosen as the software to control the Chimera. It generates the images for the projector, and controls the Z axis. The SLA process allows for high definition printing, and the results are rather impressive for such a cheap device. This is something we were just talking about yesterday; how to lower the cost of 3D printers. Obviously this is cheating a bit because it’s banking on the availability of cheap used parts. But look at it this way: it’s based on older technology produced at scale which should help a lot with the cost of sourcing this stuff new. What do you think?

Youthful Destruction at Maker Faire

 

Who didn’t get in trouble for taking things apart as a kid? The TakeItApart booth at the 2014 Maker Faire was among my favorite. It let anyone (especially the kids) grab a piece of electronics headed for recycling and crack it open just to see what is inside. The good news being that you didn’t need to be able to put it back together again since it’s just going to be ground up for its constituent materials anyway.

There’s something cathartic about watching a 7-year-old stabbing at a Walkman radio with a slotted screwdriver (those plastic cases are more robust than you might think). I asked if anyone had managed to slice open their hand back-to-the-future style in the process and thankfully the answer was no. But there was at least one instance of “free daycare” where the parents wandered off — there are plenty of distractions at MF — much to the chagrin of their progeny.

Seeing this made me think of this recent interview with [Bunnie Huang] in which he mentions taking chips out of their sockets on an Apple II when he was a kid. He would pull them and replace them backwards to see what effect it would have. Ha! If you have a similar childhood experience to share we’d love to hear about it in the comments. If you just want to see the guts of a bunch of stuff head of to TakeItApart.

Kindle weather and recycling display

kindle-weather-and-recycling-display

We’ve seen a fair number of hacks like this one that reuse a Kindle basically just for its ePaper display. [HaHaBird] has this device hanging on his refrigerator to display the weather and remind him about recycling day. It kind of make us wonder why we’re not seeing cheap ePaper modules on the hobby market?

The concept isn’t new, but [HaHaBird] does move it along just a little bit. He started by following the guide which [Matt] wrote after pulling off the original Kindle weather display hack. It uses a separate computer running a script that polls the Internet for weather data and generates a vector graphic like the one seen above. The Kindle then loads the image once every five minutes thanks to a cron job on the rooted device. But why stop there? [HaHaBird] tweaked the script to include a reminder about his municipality’s irregular recycling schedule.

Don’t overlook the quality of the hardware side of this hack. With its prominent place in the kitchen he wanted a nicely finished look. This was achieved by building a frame out of cherry and routing passages on the back to make room for the extension cable (so it could hang in landscape orientation) and a toggle to hold the Kindle firmly in place. Additional information on the build is available here.

Science fair project sorts recyclables

This crew of high schoolers built a sorting robot for the Smart Young Mindz challenge. We got pretty excited when hearing that it sorts plastic by its recycling code, but unfortunately this isn’t quite what it’s made out to be. The device uses an RFID code on each product to figure out where it goes. Their thinking is that at some point every product sold will have an embedded tag in it. For now this will not revolutionize the recycling industry, but the build is still impressive. We’re sure they learned a ton from all of the mechanical engineering that went into the project.

You can see the three laundry baskets that serve as the sorting bins. The white box above the bin on the right is the hopper in which a plastic container is placed. The box can then revolve around a central axis to position itself over the correct basket. The floor of the box is then retracted, dropping the refuse in the bin. Check out the video after the break for the satisfying cry of the servo motors at work.

We like seeing recycling robots, but so far most of what we’ve seen are aluminum can crushers.

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Tutorial series shows you everything you need to salvage transformers from microwaves

Transformers certainly have a tendency to increase the cost of any project, especially if you need a large transformer to get the job done. Microwave ovens are great sources of free transformers, though they are not always in the shape required for your next build.

[Matt] put together three great tutorial videos covering the basics of salvaging Microwave Oven Transformers (MOTs), that anyone new to the process should watch before giving it a go. The first video covers MOT removal and disassembly, which is a time consuming yet easy process providing you follow [Matt’s] pointers.

The second video delves into transformer theory, and discusses how to achieve optimal performance when rebuilding an MOT or hand wrapping coils to fit your project specs. The third video in the series follows [Matt] as he rebuilds one of the salvaged transformers, documenting his pitfalls and successes along the way.

If you haven’t given much thought to salvaging MOTs, we definitely recommend taking a bit of time to watch the video series in full – it’s definitely worth it.

You can see the first video in the series after the jump – the rest can be found via the YouTube link above.

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A.R.T. sorts your recyclables for you

[Yuhin Wu] wrote in to let us know about the Automated Recycling Sorter that was built with a group of classmates at the University of Toronto. They entered it the school’s student design contest and we’re happy to report that it took first place.

The angled sled has been designed to separate glass, plastic, and metal containers. The first sorting happens at the intake area. A set of moment arms are used to weed out the glass bottles. Since there are several of them in a row, a larger and heavier plastic container will not be falsely sorted and the same goes for smaller glass bottles.

With the glass out of the mix the team goes on to separate metal and plastic. An Arduino was used for this purpose. It senses an electrical disturbance caused by a metal can passing through the chute and actuates a trap door to sort it. Plastic has no effect on this sensor and slides past the trap to its own sorting bin.

Don’t miss both demo videos which we’ve included after the break.

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