A man with dark skin in a red shirt and khaki shorts sits in a chair. His left leg has a prosthetic below the knee. The upper half of the prosthethic is an off white plastic socket with flecks of different off white plastic throughout hinting at the recycled nature of the plastic. The lower half is a metal tube attached to an artificial foot in black sandals.

Precious Plastic Prosthetics

February 20, 2023 by Navarre Bartz 8 Comments

Plastic waste is a major problem, but what if you could turn the world’s trash into treasure? [Yayasan Kaki Kita Sukasada (YKKS)] in Indonesia is doing this by using recycled plastic to make prosthetic legs.

Polypropylene source material is shredded and formed into a sheet which is molded into the required shape for the socket. A layer of cloth and foam is used to cushion the interface between the patient and the socket itself. Using waste plastic to make parts for the prosthetics lowers the price for patients as well as helps to keep this material out of the landfill.

What makes this project really exciting is that [YKKS] employs disabled people who develop the prosthetics and also trains patients on how to maintain and repair their prosthetics with easily sourced tools and materials. With some medical device companies abandoning their devices, this is certainly a welcome difference.

We’ve previously covered the Precious Plastic machines used to make the plastic sheets and the organization’s developments at small scale injection molding.

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An Open Source Detector For Identifying Plastics

December 13, 2021 by Tom Nardi 18 Comments

One of the challenges involved in recycling plastic is determining the specific type of plastic a given item is actually made of. To keep up with demand, large scale recycling centers rely on various automated systems to separate different types of plastic from a stream of incoming material. But in less technologically advanced parts of the world, workers can find themselves having to manually identify plastic objects; a time consuming and error-prone process.

To try and improve on the situation, [Jerry de Vos], [Armin Straller], and [Jure Vidmar] have been working on a handheld open hardware device that they refer to simply enough as the Plastic Scanner. The hope is that their pocket-sized unit could be used in the field to positively identify various types of plastic by measuring its reflectivity to infrared light. The device promises to be very easy to operate, as users simply need to bring the device close to a piece of plastic, push the button, and wait for the information to pop up on the OLED display.

Or at least, that’s the idea. While the team eventually hopes to release a kit to build your own handheld Plastic Scanner, it seems that the hardware isn’t quite ready for production. The most recent work appears to have been put in, not unexpectedly, the development board that lets the team refine their process. The development unit combines an array of IR LEDs with wavelengths ranging from 850 to 1650 nanometers, a InGaAs photodiode connected to an ADS1256 24-bit analog-to-digital converter (ADC), and an Arduino Uno. In comparison, the final hardware uses a Raspberry Pi Zero and a smaller “breakout board” that contains the sensor and IR LEDs.

Browsing through the software repository for the project, we can see the device uses Python, TensorFlow Lite, and a database of IR reflectivity values for known plastics to try and determine the closest match. Obviously the accuracy of such a system is going to be highly dependent on the quantity of known-good data, but at least for now, it appears the user is responsible for building up their own collection or IR values.

As interesting as this project is, we’re a bit skeptical about its purely optical approach to identifying plastics. Automated recycling centers do use infrared spectroscopy, but it’s only one tool of many that are employed. Without additional data points, such as the density or electrostatic properties of the plastic being tested, it seems like the Plastic Scanner would have a fairly high margin of error. Just taking into account the wide array of textures and colors the user is likely to encounter while using the device will be a considerable challenge.

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These Plastic Pavers Are Earth Savers

February 7, 2021 by Kristina Panos 102 Comments

Plastic waste is everywhere you look, and there’s seemingly no end in sight for both the demand and production of plastic goods. So isn’t it time to try putting all that waste from the plastic industry to good use? [Nzambi Matee], a materials engineer in Kenya, thinks so. She was tired of seeing plastic littering the streets of Nairobi, and saw an opportunity to solve two problems at once — cleaning up the streets and paving them with plastic.

Three years ago, [Nzambi] quit her job as an oil industry data analyst and used all her savings to pursue a solution for the pesky plastic problem. She built a lab in her mother’s backyard and begin experimenting with plastics and sand, melding them together to make blocks.

After about a year of trial and error, she had discovered which plastics worked and which didn’t. Then she developed machinery to churn out the sand-plastic paste and stamp it into sturdy paving bricks. Her company Gjenge Makers gets most of their plastic free from factories that would otherwise have to pay to dispose of it. The bricks are strong, lightweight, and nearly indestructible compared to concrete pavers. In the video after the break, there’s a shot of [Nzambi] spiking one on the ground to demonstrate its toughness.

Now, her company produces about 1,500 of these pavers each day. [Nzambi] and her team are planning to start making building blocks as well. With a melting point somewhere above 350° C, the material seems pretty well-suited for that purpose.

Want to do more than just recycle your plastic, but don’t know how? You could start by turning plastic bottles into rope, and then use the rope to make things like brooms and brushes.

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School Project Turns Plastic Waste Into Bricks

October 31, 2020 by Lewin Day 66 Comments

Many plastics are, in theory at least, highly recyclable. Unfortunately, in reality, most plastic ends up as waste instead, harming the environment and providing no ongoing value to society. Wanting to investigate possible ways to repurpose this material, [Rehaan33] built a rig to create bricks out of waste plastic for a school project.

The aim of the project is to take waste plastic, in this case high-impact polystyrene, and reform it into a brick that could be used as a low-cost building material. The material is shredded, before being packed into a steel mould and heated to 270 degrees in an oven. As polystyrene is a thermoplastic, it can readily be heated in this way for reforming without harming the material’s properties. Once heated, the mould is placed into the press rig, which uses parts of an old drill press to force down a steel plate, helping shape the final form of the brick.

While you’re unlikely to see old soda bottles used to build a skyscraper in New York any time soon, such techniques could be a good way to help eliminate plastic waste in impoverished areas and stem the flow of plastic into the world’s oceans. The project served as a useful learning experience, allowing [Rehaan33] to pick up skills in metalworking, machine design, and working with thermoplastics. Recycling plastics is a key area of interest for many, particularly in the 3D printing space, with many exploring ways to reuse thermoplastics in more efficient ways. If you’ve got your own project turning waste plastics into useful material, be sure to let us know!

Print Your Own Filament

June 2, 2018 by Al Williams 25 Comments

Ask anyone with a 3D printer what they make the most. They’ll probably say “trash.” There are extra pieces, stuff that oozes out of the extruder, support material, parts that didn’t stick to the bed, or just parts that needed a little tweaking to get right. No matter what you do, you are going to wind up with a lot of scraps. It would be great if you could recycle all this, and [3D Printing Nerd] looks at the FelFil Evo Filament extruder that promises it can do just that. You can see the video below.

As you’d expect, the device is a motorized auger that extrudes filament through a hot end not dissimilar to your printer’s hot end. You have to run a bag of special material through it first to clean out the plastic path. After that, you can create filament from standard pellets or pieces of old plastic.

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Recycling And Casting Styrofoam With Solvents

May 1, 2018 by Lewin Day 30 Comments

Styrofoam is an ever-present waste material in modern society, being used to package everything from food to futons. It’s also not the easiest thing to deal with as a waste stream, either. With this in mind, [killbox] decided to have a go at recycling some styrofoam and putting it to better use.

The process starts by combining the EPS styrofoam with a solvent called D-limonene. This was specifically chosen due to its low toxicity and ease of use. The solvent liquifies the solid foam and the air bubbles are then allowed to make their way out of the solution. If it’s desired to create a coloured end product, it’s noted that this can be achieved by using other plastic items to provide colour at this stage, such as a red Solo cup.

It’s a slow process thanks to the choice of solvent, but it makes the process much more palatable to carry out in the average home lab setup. It’s possible to then perform casting operations or further work with the recovered material, which could have some interesting applications. It’s not the first plastics recycling project we’ve seen, either – check out this full setup.

[Thanks to Adric for the tip!]

Omaha Mini Maker Faire: Recycle All The Things

September 21, 2015 by Kristina Panos 13 Comments

A young maker named [Allie] drew a lot of attention at the 2nd annual Omaha Mini Maker Faire. Her booth was full of the various creations she has designed and built herself throughout the course of her short life. The biggest draw was her green design dollhouse, which focuses on environmentally friendly living. With the exception of the LEDs lighting the interior, some tape, and the requisite bit of hot glue, the entire structure and its contents were made from recycled materials.

The cardboard structure features a kitchen, living room, bedroom, bathroom, and attic. Every piece of furniture and all the decorations are made from salvaged materials and packaging. One side of the roof holds a Snap Circuits board with a solar panel that powers some blue LEDs on the bedroom wall. [Allie] poured water down the other side of the roof to demonstrate the rain water collection system. The house’s rain barrel was made from a grated parmesan cheese container, which is perfectly designed for the airline tubing running into it from the recycled plastic guttering.

One of [Allie]’s other projects is a disagreeable owl fashioned from cardboard and a salvaged canister. Hidden away beneath the owl’s platform lies a simple gear system attached to a key on the front. Turning the key causes the owl’s head to swivel back and forth. We tried to make it spin all the way around, but the full range of motion is about 270 degrees. She also brought Mountain Dew, a hummingbird model made from a spark plug and other metal bits and bobs, including a pair of soda can wings.

In addition to her crafty skills, [Allie] is one well-spoken tween. She was more than happy to discuss her creations in detail to anyone who would listen, which included at least two local journalists and this impressed reporter. We learned through a bit of light research that a robot [Allie] built a few years ago inspired a British toy company to produce a new doll, the Robot Girl Lottie. She’s an inspiration to makers of all ages.