Bicycle Inner Tube Becomes Rugged Pencil Case

November 12, 2022 by Lewin Day 23 Comments

If you’re a cyclist that lives in an area with poorly-maintained infrastructure, you’ll likely have plenty of punctured inner tubes begging for reuse. Consider crafting them into a rugged, hard-wearing pencil case with this design from [Yorkshire Lass].

[Yorkshire Lass] does a great job of not only explaining the basic design of the pencil case, but also the unique techniques required to work with inner tubes in this manner. For best results, the tube must first be straightened by stretching it for some time along a flat board. Strips of the rubber must then be cut to suit, and then assembled into the pattern to make the pencil case. Sewing up the case also requires some special techniques outside those used in regular sewing. That’s largely down to the fact that rubber can’t be pinned in place without leaving a permanent hole in the material. Thankfully, the write-up explains all the traps for those new to sewing inner tubes, which we’d have to suspect is most of us.

Assembled properly, you’ll end up with a pencil case made of far tougher material than most. Plus, it makes a great fashion accessory to flaunt to other bicycle or recycling evangelists at your school, college, or workplace. Even better, there’s scope to run a group craft session with your local bike group given everyone surely has a few dud mountain bike tubes laying around.

We’ve seen some other neat hacks intended to store pens and pencils around the workshop. Meanwhile, if you’ve got your own great reuse ideas for old bicycle inner tubes, do drop us a line!

3D Printer Repurposed For Light-Duty Lab Automation Tasks

November 11, 2022 by Dan Maloney 3 Comments

Laboratory automation equipment is expensive stuff, to such a degree that small labs are often priced out of the market. That’s a shame, because there are a lot of tedious manual tasks that even modest labs would benefit from automating. Oh well — that’s what grad students are for.

But it actually isn’t that hard to bring a little automation to the lab, if you follow the lead of [Marco], [Chinna], and [Vittorio] and turn a 3D printer into a simple lab robot. That’s what HistoEnder is — a bog-standard Creality Ender 3 with a couple of special modifications that turn it into a tool for automating histology slide preparation. Histology is the study of the anatomy of tissues and uses various fixing and staining techniques to make microscopic features visible. In practice, this means moving baskets of glass slides back and forth between jars of different solutions, a job that’s perfect for a simple Cartesian gantry lab robot with a small work envelope and light loads.

None of the printer modifications are permanent; the 3D printed accessories — a hook for the slide basket and a carrier for standard histology staining jars — can quickly come off the printer to return it to its regular duty. All it takes to run HistoEnder is a bit of custom G-code and some careful alignment of the jar carrier on the print bed. We suppose the bed heater could even be used to warm up the fixing and staining solutions. There’s a brief video of HistoEnder in action embedded in the tweet below.

This isn’t the first time this team has repurposed technology for the lab — remember the fitness band that was turned into an optical densitometer?

Continue reading “3D Printer Repurposed For Light-Duty Lab Automation Tasks” →

Chevron Desk Takes Advantage Of Plywood For Patterning

November 8, 2022 by Lewin Day 23 Comments

Buying a desk is all well and good, but [WoodCraftly] found that the options they found online were too pricey for what was being offered. Buying the table frame from scratch was much cheaper, and just required crafting a top to match. That provided the opportunity to create this beautiful herringbone-finish desk created with some simple woodworking techniques.

Plenty of clamps were needed for the glue-up.

The build starts with a motorized corner desk frame that can be bought from amazon for just $550. To create the chevron-finish top, [WoodCraftly] grabbed some plywood sheets, and cut them into a series of 1-inch strips. These were then flipped 90-degrees onto their side, and glued together to create a panel that showed off the individual layers of the plywood. This panel was then cut into 3-inch wide strips at a 45-degree angle, and these strips were then placed back to back and once again glued up to create the attractive herringbone design.

From there, it was a simple matter of gluing up panels into the L-shape required for the desk, adding mounting holes, and rounding off the corners for a nice finish. The desk was also given a thick coat of epoxy on the bottom which soaked into the wood and helped give the desk some strength, and a top coat that was sanded back to a natural-look finish.

Overall, the final desk is just the product of some smart cutting and gluing steps combined to create a fun pattern in the end. It’s always fun to build your own furniture because you can express your own style in your creations. Video after the break.

Continue reading “Chevron Desk Takes Advantage Of Plywood For Patterning” →

Overengineered Fume Extractor, Version 2

November 7, 2022 by Al Williams 12 Comments

We all know the temptation of adding one more feature to your latest project. [Arnov Sharma] didn’t resist the urge. Building on his 3D-printed fume extractor, he developed a new version made of PCB material.

The device has a 18650 battery and corrects several flaws in the original design we covered earlier. In particular, the new version uses a quiet fan and consumes less power. There is also a 3D-printed filter housing that uses cotton as a filter media. Continue reading “Overengineered Fume Extractor, Version 2” →

An RP2040 Powered Pick And Place

November 7, 2022 by Matthew Carlson 15 Comments

Pick and place machines are a wonder to behold, as they delicately and accurately place part after part. Unfortunately, they have to have a similarly wondrous price tag. Luckily, they aren’t too difficult to make yourself as they share many properties of a 3D printer with some extra constraints. [Stargirl Flowers] released Starfish, an open-source pick-and-place control board based around an RP2040 to help people make their own.

She purchased a LumenPnP, and the itch to tinker became too much to ignore. The STM32 on the stock controller also happened to get fried, leaving an obvious opening to create a custom board. [Stargirl] chose Trinamic TMC2209 motor controllers to drive the three stepper motors. The power circuit is impressively overbuilt with a 3A fuse, a TVS diode for shunting voltage spikes, a P-channel MOSFET for reverse polarity protection, a low-pass filter for AC ripple, and a large 100μF capacitor.

The RP2040 is a good choice since it’s easy to get and has plenty of digital I/O. USB connects the board to the outside work and includes ESD TVS diodes to protect the board when connecting and disconnecting the USB port. Motors for vacuums are controlled by a 74HC2G34 buffer that drives enable lines to two MOSFETs. Solenoids are similar but with a high current peak and a much smaller current to keep them open. The DRV120 fits the bill as it is a single-channel relay with current regulation. I2C vacuum sensors are the same ones on the Lumen motherboard; they just required an I2C multiplexer.

It’s an extremely well-documented project explaining why each part was chosen and why. If you want to create an RP2040 project that needs to last, we consider this a guiding star. It’s all up on GitHub for you to take a look at.

This isn’t the first time we’ve seen RP2040 as part of a motor controller, and we suspect we’ll see more.

"The Great Resistor" color code illumination project

The Great Resistor Embiggens The Smallest Value

November 5, 2022 by Dave Walker 29 Comments

With surface-mount components quickly becoming the norm, even for homebrew hardware, the resistor color-code can sometimes feel a bit old-hat. However, anybody who has ever tried to identify a random through-hole resistor from a pile of assorted values will know that it’s still a handy skill to have up your sleeve. With this in mind, [j] decided to super-size the color-code with “The Great Resistor”.

Resistor color code from Wikipedia with white background — How the resistor color-code bands work

At the heart of the project is an Arduino Nano clone and a potential divider that measures the resistance of the test resistor against a known fixed value. Using the 16-bit ADC, the range of measurable values is theoretically 0 Ω to 15 MΩ, but there are some remaining issues with electrical noise that currently limit the practical range to between 100 Ω and 2 MΩ.

[j] is measuring the supply voltage to help counteract the noise, but intends to move to an oversampling/averaging method to improve the results in the next iteration.

The measured value is shown on the OLED display at the front, and in resistor color-code on an enormous symbolic resistor lit by WS2812 RGB LEDs behind.

Inside view of the great resistor showing WS2812 LEDs and baffle plates — Inside The Great Resistor, the LEDs and baffle plates make the magic work

Precision aside, the project looks very impressive and we like the way the giant resistor has been constructed. It would look great at a science show or a demonstration. We’re sure that the noise issues can be ironed out, and we’d encourage any readers with experience in this area to offer [j] some tips in the comments below. There’s a video after the break of The Great Resistor being put through its paces!

If you want to know more about the history of the resistor color code bands, then we have you covered. Alternatively, how about reading the color code directly with computer vision?

Continue reading “The Great Resistor Embiggens The Smallest Value” →

3D Printed Newtonian Telescope Has Stunning Looks, Hadley Breaks The Bank

November 4, 2022 by Ryan Flowers 49 Comments

Have you ever considered building your own telescope? Such a project can be daunting, especially if you grind your own mirrors. But with a 3D printer, hardware store bits and bobs, and some inexpensive pre-made mirrors, you too can be the proud owner of your very own own Hadley — a 114/900mm Newtonian Telescope that can cost less than $150 USD to build! Check out the video below the break to get a good scope on the project.

Astrophotography is possible with the Hadley

The creator’s stated goal is to “make an attractive alternative to the shoddy, hard to use “hobby-killer” scopes in the $100-200 range“, and we have to say that it appears to have met its goal admirably. The optics — the most complex part of any build — can be easily purchased online, and the rest of the parts are available at your local hardware store.

While the original build was provided in Imperial measures, a metric version is now available. Various contributors have created a rich ecosystem of accessories and alternative versions of various parts, all in the interest of making the telescope more useful. Things like tripod mounts, phone mounts (for use with your favorite star chart app) and more are only a click away. The only real question to answer is “What color filament will I use?”

Of course, sometimes light waves can get a bit long in the tooth, and for those cases you’ll want a radio telescope, which can also be DIY’d thanks to the availability of satellite dishes and SDR dongles!

Continue reading “3D Printed Newtonian Telescope Has Stunning Looks, Hadley Breaks The Bank” →