Page-Turning Pedal Is Pretty Boss

October 16, 2020 by Kristina Panos 2 Comments

Buying things to make your life easier certainly has its therapeutic joys, but if you really wanna feel good, you gotta make the thing yourself whenever possible. [Bjørn Brandal] happened to have a two-switch BOSS pedal just lying around, so it made sense to turn it into a wireless page turner for reading sheet music.

As [Bjørn] says, the circuit is simple — just two 1/4″ TRS jacks and an ItsyBitsy nRF52840 Express. The jacks are used to connect to the pedal outputs to the ItsyBitsy, which sends keystrokes over BLE.

The cool thing about this pedal is that it can work with a bunch of programs, like forScore, Abelton Live, Garage Band, and more. The different modes are accessed by holding down both pedals, and there’s confirmation via blinking LED and buzzing buzzer.

Our favorite part has to be the DIY light guide [Bjørn] that bends the ItsyBitsy’s RGB LED 90° and points it out the front of the enclosure. Nicely done!

Don’t play anything but the computer keyboard? Put those feet to work with shortcuts behind giant arcade buttons.

Benchtop Injection Molding For The Home Gamer

October 16, 2020 by Lewin Day 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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Building An Internet Radio Is Quick And Easy With The ESP32

October 15, 2020 by Lewin Day 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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A Lawnmower That Looks Where You’re Going

October 15, 2020 by Matthew Carlson 21 Comments

As a kid, one of the stories my dad told me was about mowing a fairly large field of grass on the farm with a gas-powered push mower. One day, some sort of farm tool was left in the field and the old industrial mower shredded it, sending a large piece of sharp metal hurtling toward his leg. Luckily for my dad, the large plastic wheel managed to stop the piece of metal, destroying the wheel. My grandfather was frustrated that he needed to repair the lawnmower but was grateful that my dad still had both feet attached.

Of course, this story was used as a lesson for me not to gripe about having to mow the lawn when it was my turn, but there was also the lesson that lawnmowers can be dangerous. [DuctTape Mechanic] took it upon himself to see if he could prevent that sort of accident altogether and has created an automatic safety shutdown mechanism for his family lawnmower. (Video embedded below.)

This uses an inductive sensor that can detect metal before it gets sucked into the mower itself. The sensor trips a relay which forcibly shuts the mower down by grounding the ignition coil. While it doesn’t physically stop the blade like other safety mechanisms, it does prevent a situation from escalating by turning off power to the blade as soon as possible. Getting to the ignition coil wasn’t easy as it required getting deep into the engine itself, but now [DuctTape Mechanic] has a mower that could be expanded further with things such as with a capacitive sensor or more smarts to determine if it is detecting underground or above ground metal.

Someday we’ll have robotic mowers, but until then, we laud the efforts of hackers out there trying to make the world a little safer.

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Air Cannon Serves Up A Blast Of Ferrocerium Sparks

October 15, 2020 by Dan Maloney 25 Comments

OK, looks like we have a new way to entertain the kids and wreak havoc in the neighborhood, if this spark-shooting ferrocerium cannon is as easy to build as it looks.

This one comes to us by well-known purveyor of eyebrow-singing projects [NightHawkInLight], whose propane torch never seems to get a break. The idea here is a large scale version of an apparently popular trick where the “flints” from lighters, which are actually rods of ferrocerium, an aptly named alloy of iron and cerium, are heated to a nearly molten state and dropped onto a hard surface. The molten alloy thence explodes in a shower of sparks, to the mirth and merriment of those in attendance.

[NightHawkInLight]’s version of the trick scales everything up. Rather than lighter flints, he uses ferrocerium rods from firestarters of the type used for camping. The rod is stuffed into a barrel formed from steel brake line which is connected to the output of a PVC air chamber. His ominpresent propane torch is attached in such a way as the flame plays upon the loaded pyrophoric plug, heating it to a molten state before the air is released from the chamber. The massive display of sparks seen in the video below is pretty impressive, but we’re getting tired of gender reveal parties and forest fires. We just hope he had fire extinguishers on hand.

Seriously, be careful with stuff like this. [NightHawkInLight] has a lot of experience working with these kinds of projects, from his plasma-propelled soda bottles to making synthetic rubies with an arc welder. We’re sure he wouldn’t want to see anyone get hurt.

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Homebrew Pulsejet Uses Carbon Fiber To Great Effect

October 14, 2020 by Lewin Day 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 Lewin Day 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!