Benchtop Injection Molding For The Home Gamer

October 16, 2020 by Zoe Skyforest 8 Comments

When we think injection molding, the first thing that comes to mind is highly automated production lines pumping out thousands of parts an hour. However, the very same techniques are able to be scaled down to a level accessible by the DIYer, as [The CrafsMan] demonstrates.

Using a compact, hand-actuated injection moulder, [The Crafsman] demonstrates the basic techniques behind small-scale injection molding. The PIM-Shooter Model 150A in question is designed to work with low melting point plastics like polypropylene and low density polyethylene, and can use aluminium molds which are much cheaper to make than the typical steel molds used in industry.

However, the real game changer is when [The Crafsman] busts out his silicone mold making techniques, and applies them to injection molding. By making molds out of silicone, they can be created far more cheaply and easily without the requirement of heavy CNC machinery to produce the required geometry. With the right attention to detail, it’s possible to get good results without having to invest in a custom aluminium mold at all.

Injection molding is a process that can achieve things 3D printing and other techniques simply can’t; it can even be used to produce viable lenses. Video after the break.

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Clear PS2 Is The Crystal Edition We Deserved

October 15, 2020 by Zoe Skyforest 13 Comments

Every so often, console manufacturers release a crystal edition of their hardware that never really lives up to the hype. The manufacturing realities of producing optically clear plastic mean the expense is rarely justified, even for a special edition. Instead, we get hazy, smoky translucent cases that are comparatively underwhelming. Here to rectify that, [BitHead1000] delivers on a properly transparent PlayStation2.

While the title calls it a Glass PS2, the cutting tools used and the labels on the material make it pretty clear (pun intended) that this build uses acrylic. Regardless, it’s an attractive material all on its own, and much more suited for such a build. To get the best possible visual effect, the internal shielding is removed and tossed in the bin, with plastic standoffs used to hold things in place instead. The case is then assembled around the components, giving an unparalleled view of the hardware inside.

It’s undeniably cool to watch the optical drive doing its thing inside the case when it’s switched on, and a few internal LEDs only add to the spectacle. We’ve seen [BitHead1000] pull off other casemodding feats, too, such as the fire breathing N64. Video after the break.

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Building An Internet Radio Is Quick And Easy With The ESP32

October 15, 2020 by Zoe Skyforest 20 Comments

Terrestrial radio is all well and good, but it limits you to listening to local stations. [Nick Koumaris] lives in a small town in Southern Greece, and his favorite stations sadly don’t transmit in his area. Thus, an internet radio was the natural solution.

[David Watts] did a similar build, throwing the hardware inside a stunning Roberts RM20 radio from the 1970s.

While a Raspberry Pi is a common way to go in these situations, an ESP32 has enough grunt to do the job without the long boot times that come with running a full Linux distribution. Combined with a VS1503 MP3 decoder board and a PAM8403 amplifier, it’s more than capable of tuning in streams online. [Nick] went with a retro-look interface on an LCD, using a Nextion part for its onboard controller and in-built GUI tools. Taking inspiration from the project, [David Watts] executed a similar build, but instead used an Arduino Nano to interface the controls on a vintage Roberts RM20 radio instead.

While we’ve all got smartphones we can use to listen to content online, it can be nice to use a device that allows us to put on some music without constant notifications and chimes every time an email comes in or a government scandal erupts in a nearby country. When building your own radio, you can tailor the interface to suit your tastes – like this build that lets users scan the globe for a station to listen to. Video after the break.

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Homebrew Pulsejet Uses Carbon Fiber To Great Effect

October 14, 2020 by Zoe Skyforest 21 Comments

Jet engines are undeniably awesome, but their inherent complexity prevents many from experimenting with the technology at home. Perhaps the most accessible design is the pulsejet; in valveless form, it can be built relatively easily without needing a lot of precision spinning parts. [Integza] decided to try building his own, facing many hurdles along the way. (Video, embedded below.)

Despite eschewing turbines and compressors, and consisting of just an intake, exhaust and a combustion chamber, the pulsejet still presents many challenges to the home gamer. Primary concerns are sustaining combustion without the jet flaming out, and building the jet out of suitable materials that won’t simply melt into a gooey puddle on the floor.

[Integza]’s design process began with many 3D-printed attempts. While the geometry was on point, none of these designs could run for more than a few seconds without melting and falling apart. Determined to avoid the typical welded-steel approach, [Integza] instead resolved to go left-of-field with carbon fibre mat combined with high-temperature sealant. With the help of a 3D-printed mold, he was able to produce a working engine that could stand up to the high temperatures and produce that glorious pulsejet sound.

It’s come a long way from [Integza]’s earlier experiments, and we look forward to seeing where it goes next – whether that be on a plane or perhaps even a go-kart. Video after the break.

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Making A Servo Tester Just A Bit Better

October 13, 2020 by Zoe Skyforest 9 Comments

Servo testers are useful devices to have on hand, allowing one to quickly check a given part for proper operation. However, cheaper models can be quite limited, and may not output signals suitable for testing the full range of servos out there. [Buttim] had a few testers laying around, and wanted to see if they could be modified to do more.

Initial experiments with the cheapest model on hand came to naught, revealing nothing but a small IC with its markings scrubbed off. However, going a few more dollars upmarket, [buttim] found a servo tester packing a Nuvoton N75E003. An unfamiliar name to the hobbyist, Nuvoton microcontrollers are often found in mass-production designs due to their low cost.

The N75E003 is a 8051-based device, and [buttim] was able to source a programmer and tutorial resources on how to work with the chip. Armed with the right hardware and knowledge, the servo tester was first programmed with a basic blink sketch. With everything confirmed to be working as expected, [buttim] set about programming a custom firmware for the servo tester that would output a broader range of PWM signals to suit their needs.

It’s a great example of the learning possibilities available by simply cracking open the case of commodity hardware and diving in. Of course, if you need something even more capable, you can always build your own from scratch!

Robot Gets Around On All Fours, Thanks To Many, Many Servos

October 13, 2020 by Zoe Skyforest 2 Comments

As far as robots are concerned, wheels and tracks are great ways to get around when you’ve got serious work to do. However, if you want to build something that feels more animal than machine, building a walking ‘bot is the way to go. [Technovation] delivers a great example in the form of this quadruped design.

It’s a build executed in the modern style, taking full advantage of contemporary design tools and processes. The entire robot is built around twelve servo motors that provide rotation and translation to the robot’s joints. After importing the servo models into Fusion 360, [Technovation] set about building the rest of the body around them. An Arduino Uno runs the show, which addresses the many servos thanks to a Sensor Shield that has a multitude of useful outputs.

[Technovation] put a specific focus on durability and robustness during the design phase. The platform is intended as a test bed for various walking styles and gaits, and thus any hardware failures would be an unnecessary distraction from the project’s goals. The chassis is a great platform to learn on, and we expect to see further developments in future.

The eerily lifelike robots from Boston Dynamics may have set a high bar, but DIYers are still out there having a crack at building capable walking robots. Video after the break.

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Running Way More LED Strips On A Raspberry Pi With DMA

October 12, 2020 by Zoe Skyforest 18 Comments

The Raspberry Pi is a powerful computer in a compact form factor, making it highly useful for all manner of projects. However, it lacks some of the IO capabilities you might find on a common microcontroller. This is most apparent when it comes to running addressable LED strings. Normally, this is done using the Pi’s PWM or audio output, and is limited to just a couple of short strings. However, [Jeremy P Bentham] has found a way to leverage the Pi’s hardware to overcome these limitations.

The trick is using the Raspberry Pi’s little-documented Secondary Memory Interface. The SMI hardware allows the Pi to shift out data to 8 or 16 I/O pins in parallel using direct memory access (DMA), with fast and accurate timing. This makes it perfect for generating signals such as those used by WS2812B LEDs, also known as NeoPixels.

With [Jeremy]’s code and the right supporting hardware, it’s possible to run up to 16 LED strips of arbitrary length from the Raspberry Pi. [Jeremy] does a great job outlining how it all works, covering everything from the data format used by WS2812B LEDs to the way cache needs to be handled to avoid garbled data. The hack works on all Pis, from the humble Pi Zero to the powerful Pi 4. Thanks to using DMA, the technique doesn’t overload the CPU, so performance should be good across the board.

Of course, there are other ways to drive a ton of LEDs; we’ve seen 20,000 running on an ESP32, for example.

[Thanks to Petiepooo for the tip!]