Tiny Palm-Sized Crossbow Build Is Cute And Dangerous

November 17, 2022 by 17 Comments

Crossbows were a major development in the history of weaponry. They enabled lesser-skilled soldiers to shoot arrows at great speed in a compact form-factor. You can now build your own tiny version, thanks to this creation from [Maciej Nowak].

The main body of the crossbow was cut from a piece of aluminium bar stock, being shaped with an angle grinder. A slot was then machined to mount the crossbar and pulleys. A round piece of aluminium tube serves as a spring holder, and the spring is tensioned via pulling back a length of sailing rope to rest on a latch. The latch is released by a small trigger, just like on a full-size crossbow.

The arrows (or bolts, more typically) were made by machining skewers and giving them hard metal tips cut from nails. This enables them to penetrate apples, and presumably other fruits. They fly straight enough to reliably hit a target from a meter or two away.

We’ve seen other crossbow builds before, like this one that fires cannonballs! Just be careful where you aim, and don’t get yourself or anyone else hurt.

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Number Stations Gone Wild

November 17, 2022 by 18 Comments

[Ringway Manchester] has an interest in numbers stations. These mysterious stations send presumably coded numbers or other coded information. However, it is rare that anyone claims credit for these stations. Normally they operate with military-like precision, adhering to strict operating schedules and sending out their messages error-free. [Ringway] looks at five times when things didn’t go as planned for these spy stations.

Perhaps it isn’t surprising, however, as machines have likely replaced human operators. That makes them prone to errors when the computers go awry. Many of the errors are ones of frequency, where two number stations wind up transmitting at once. We suppose spies all use the same few frequencies. Some, however, also had computers go haywire and start going through the alphabet which, of course, could have been part of some secret message protocol, but appeared more likely to be a simple mistake.

We were amused, though, to hear the story of a Czech spy station that not only had a licensed call sign but would send QSL cards to people who reported reception. Perhaps they didn’t get the memo about secrecy!

We’ve listened to a few number stations in our time. If you don’t have a suitable antenna, you can always try hunting them online. But don’t expect to catch them making any mistakes.

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A 12" LCD screen sits between speakers (on lower half of bezel) and joycon controllers are attached on the upper half of the bezel.

Portable Monitor Extension For Nintendo Switch

November 16, 2022 by 7 Comments

Handheld consoles are always a tradeoff between portability and screen real estate. [Pavlo Khmel] felt that the Nintendo Switch erred too much on the side of portability, and built an extension to embiggen his Switch. (YouTube)

[Khmel] repurposed a Dell XPS 12 LCD panel for the heart of this hack and attached it to an LCD controller board to serve as an external monitor for the Switch. A 3D printed enclosure envelops the screen and also contains a battery, speakers, and a dock for the console. Along the top edges, metal rails let you slide in the official Joy-Cons or any number of third party controllers, even those that require a power connection from the Switch.

Since the Switch sees this as being docked, it allows the console to run faster and at higher resolution than if it were in handheld mode. The extension lasts about 5 hours on battery power, and the Switch inside will still be fully charged if you don’t mind being constrained to its small screen while you charge it’s bigger-screened exoskeleton.

Need more portable goodness? Be sure to check out our other handheld and Nintendo Switch hacks.

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Better Sheet Metal Parts With Chemistry

November 16, 2022 by 7 Comments

[Applied Science] wanted to make some metal parts with a lot of holes. A service provider charged high tooling costs, so he decided to create his own parts using photochemical machining. The process is a lot like creating PC boards, but, of course, there are some differences. You can see the video of the results, below.

Some of the parts could be made in different ways like water jet cutting or even stamping. However, some things — like custom screens — are only really feasible to do with a chemical process like this.

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Crazy Bike Frame Made Out Of 147 Nuts

November 16, 2022 by 39 Comments

Bike frames are most commonly made out of steel. If you’ve got money for something nicer though, you might go with something in aluminium or carbon fiber. [The Q] went completely off-the-wall with this build, though, constructing a bicycle frame out of 147 nuts. 

Those forks don’t inspire confidence.

Yes, a variety of nuts in various sizes were laid out and welded together to make the frame. The overall layout is a conventional diamond frame, albeit constructed out of many nuts stuck together rather than with tubes. Notably though, several important areas aren’t made in this way. The front and rear dropouts are made of sheet steel, and the bottom bracket, seat post mount, and headstem are all made of steel tube. After welding, the bike was given an attractive coat of grey paint. It was then laced up with the usual running gear and given a set of chunky mountain bike tires.

We wouldn’t want to push this frame too hard over bumps and jumps. The video only shows the nuts being joined with tack welds, and the front forks look particularly fragile. One suspects a decent shock loading could snap parts of the frame apart. Overall, though, it’s an eye-catching bike that has plenty of easy places to attach a lock. For an ultra-fashionable city-bound cruiser, it would be hard to beat.

We’ve featured some weird and wonderful bikes over the years, including this tasteful plywood design. Video after the break.

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PCB Hotplate Has Integrated Heating Element Traces

November 16, 2022 by 13 Comments

Normally when we talk about PCBs and hotplates, we’re talking about reflowing solder. In this build from [Arnov Sharma], though, the PCB itself is the hotplate!

The idea was to create a compact hotplate for easily reflowing small PCBs. To achieve that, [Arnov] designed a board with a thick coil trace that acts as a heating element. The full coil trace has a resistance of 1.9 ohms, and passing electricity through it generates plenty of heat. Running off a 12 volt supply, the mini hotplate is capable of reaching a maximum temperature of 214°C. Higher voltages can push that figure higher.

The board is intended to self-regulate, with an ATtiny13 onboard and a thermistor to measure temperature. However, in the initial design, this feature didn’t quite work properly. Version 2 is intended to include a better temperature sensor and a OLED screen for displaying the current temperature to the user.

We’ve seen other tiny hotplate builds before, too. They’re great for smaller projects and for hacking on the go! Video after the break.

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Is This The Smallest CP/M Machine Ever?

November 16, 2022 by 22 Comments

If you had an office word processor in the late 1970s, the chances are it ran Digital Research’s CP/M operating system. IBM went for Microsoft in the 1980s and the once-dominant player fell on hard times, but it survives today as a popular choice on retrocomputer platforms. Even the more compact Z80 systems are a little large for 2022, so when [Kian Ryan] needed the ultimate in CP/M portability it fell on a more modern piece of silicon. Hence he’s put it on a tiny RP2040-based board from Pimoroni alongside an Adafruit micro SD card breakout.

The tiny hardware is neat of course, but the real star of the show is the software. Non-CP/M aficionados will be interested to learn about RunCPM, and for this project, RunCPM 2040. This provides an emulated environment on a host microcontroller to run CP/M, allowing the operating system to be hosted on easier hardware than some of the original machines.

All this makes for a tiny development machine, but perhaps of more interest would be a machine that’s all-in-one with a display and perhaps a keyboard. The RP2040 is interesting in this case because of those programmable state machines. Could it be made to run a video display alongside RunCPM? We hope someone has a go at writing it.