Hackaday Prize Entry: Measuring 3D Magnetic Fields

Sometimes you have to start out with big goals. Ninth-graders [Finja Schneider] and [Myrijam Stoetzer] are aiming to make a magnetic field scanner that would be helpful in finding large underground metallic objects, like unexploded WWII bombs that pose a real threat whenever a new parking garage is excavated in Germany. But even big goals have to start out somewhere, so they’re gaining experience with the sensors and the math necessary to recreate 3D magnetic flux vector fields on household objects like sawblades and magnetized screwdrivers.

Magnetized screwdriver in the "valley"
Magnetized screwdriver in the “valley”

For their science-fair project, [Finja] and [Myrijam] took a mid-80s fischertechnik “toy” 2D scanner kit, mounted a 3D magnetic sensor to it, and wrote some firmware to scan around and pass the data back to a computer where they reconstructed the field lines and made some nice visualizations. Along the way, they tried a number of designs, from a DIY chassis on carbon-fiber rails to sensors with ferrofluid. They document their successes and failures equally nicely in their lab report (PDF, German). You can get a lot of the gist, however, from [Myrijam]’s blog and their Hackaday.io entry.

You might also recognize [Myrijam] from her work with [Paul Foltin] on their eye-controlled wheelchair interface. These are some really cool projects! We’re excited to see how they develop, and are stoked that the future of hacking is in such capable hands.

Pokédex Case Keeps Your Phone Powered Up So You Can Catch ‘Em All

The launch of Pokemon Go has unleashed the franchise upon the world once again but this time it’s encouraging users to get active and socialize in the great outdoors. To show off their dedication to the cause, [Npoole] 3D printed a Pokédex external battery and case to combat the game’s already legendary drain on their Galaxy S4’s resources.

Pokedex Open BackMimicking the first-generation Kanto design, [Npoole] 3D printed it in red ABS and added a small circuit with a red, yellow and green LED to complete the effect. Inside, a 18650 lithium cell provides the much-needed backup power via a micro B plug and is boosted to 5V with a LiPo charger/booster board. Despite a switch on the circuit, the battery slowly drains so that’s something to be corrected in a future version.

As you can see, there is still some room left over in the external bat–I mean–Pokédex, and [Npoole]  intends to add another battery and a cooling fan to further improve the design. The result is a little bulky, but for new and diehard fans alike, a working Pokédex definitely worth it.

While that’s printing, if you’re looking to hack your way to the perfect Poké-ball throw, try out this lo-tech addition to your Pokémon trainer kit.

[via Sparkfun]

Mechanized One-Man Sawmill

The title of ‘maker’ is conventionally applied to the young-adult age group. In the case of 84 year-old Ralph Affleck, a lifelong sawmiller, ‘maker’ perhaps undersells the accomplishment of building a fully functioning sawmill that can be operated by a single individual.

Starting in the trade at the age of 16 under his father’s tutelage, fifty years of working in sawmills saw him still loving what he did as retirement loomed. So, with pen, paper, and a simple school ruler he designed the entire shop from scratch. Decades of expertise working with wood allowed him to design the machines to account for warping and abnormalities in the timber resulting in incredibly accurate cuts.

With no other examples to guide his design — aside from perhaps old style steam-powered sawmills, and newer portable ones that he feels are inadequate for the job — much of the shop is built from scratch with scavenged parts. And, that list is impressive: four hydraulic cylinders from a Canberra bomber, levers from an old locomotive, differentials and gearboxes from a MAC and 1912 Republic trucks, a Leyland engine that operated for 13 years without the need for maintenance, and an assortment of old military and air force vehicle parts. This is complimented by his log skidder — also custom — that would look at home in a post-apocalyptic wasteland. Built from two tractors, it combines three gearboxes for 12 forward and 8 reverse gears(what!?), and can hit 42mph in reverse!

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Tearing Apart The Nintendo PlayStation

The mid 90s were a weird time for video game hardware. There were devices that could play videos from compact disks. Those never caught on. Virtual reality was the next big thing. That never caught on. The Sony PlayStation was originally an add-on for the Super Nintendo. That never caught on, but a few prototype units were produced. One of these prototype ‘Nintendo Playstations’ was shipped to a company that went into bankruptcy. Eventually, the assets of this company were put up for auction, and this unbelievably rare game console was bought by [Terry Diebold] for $75.

[Terry] allowed [Ben Heck] tear into this piece of videogame history, and he has the video proof that this was a collaboration between Sony and Nintendo.

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Hacklet 116 – Audio Projects

If the first circuit a hacker builds is an LED blinker, the second one has to be a noisemaker of some sort. From simple buzzers to the fabled Atari punk console, and guitar effects to digitizing circuits, hackers, makers and engineers have been building incredible audio projects for decades. This week the Hacklet covers some of the best audio projects on Hackaday.io!

vumeterWe start with [K.C. Lee] and Automatic audio source switching. Two audio sources, one amplifier and speaker system; this is the problem [K.C. Lee] is facing. He listens to audio from his computer and TV, but doesn’t need to have both connected at the same time. Currently he’s using a DPDT switch to change inputs. Rather than manually flip the switch, [K.C. Lee] created this project to automatically swap sources for him. He’s using an STM32F030F4 ARM processor as the brains of the operation. The ADCs on the microcontroller monitor both sources and pick the currently active one. With all that processing power, and a Nokia LCD as an output, it would be a crime to not add some cool features. The source switcher also displays a spectrum analyzer, a VU meter, date, and time. It even will attenuate loud sources like webpages that start blasting audio.


muzzNext up is [Adam Vadala-Roth] with Audio Blox: Experiments in Analog Audio Design. [Adam] has 32 projects and counting up on Hackaday.io. His interests cover everything from LEDs to 3D printing to solar to hydroponics. Audio Blox is a project he uses as his engineer’s notebook for analog audio projects. It is a great way to view a hacker figuring out what works and what doesn’t. His current project is a 4 board modular version of the Big Muff Pi guitar pedal. He’s broken this classic guitar effect down to an input board, a clipping board, a tone control, and an output stage. His PCB layouts, schematics, and explanations are always a treat to view and read!

pauldioNext we have [Paul Stoffregen] with Teensy Audio Library. For those not in the know, [Paul] is the creator of the Teensy family of boards, which started as an Arduino on steroids, and has morphed into something even more powerful. This project documents the audio library [Paul] created for the Freescale/NXP ARM processor which powers the Teensy 3.1. Multiple audio files playing at once, delays, and effects, are just a few things this library can do. If you’re new to the audio library, definitely check out [Paul’s] companion project
Microcontroller Audio Workshop & HaD Supercon 2015. This project is an online version of the workshop [Paul] ran at the 2015 Hackaday Supercon in San Francisco.

drdacFinally we have [drewrisinger] with DrDAC USB Audio DAC. DrDac is a high quality DAC board which provides a USB powered audio output for any PC. Computers these days are built down to a price. This means that lower quality audio components are often used. Couple this with the fact that computers are an electrically noisy place, and you get less than stellar audio. Good enough for the masses, but not quite up to par if you want to listen to studio quality audio. DrDAC houses a PCM2706 audio DAC and quality support components in a 3D printed case. DrDAC was inspired by [cobaltmute’s] pupDAC.

If you want to see more audio projects and hacks, check out our new audio projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Isolated Voltage Measurements Through Frequency

This one’s not a flashy hack, it’s a great piece of work and a good trick to have up your sleeve. Sometimes you’ve got a voltage difference that you’d like to measure, but either the ground potential is at a different level, or the voltages are too high for your lowly microcontroller.

There are tons of tricks with resistive voltage dividers that you can play. But if you want serious electrical isolation from the target, there’s only one way to go — an optocoupler. But optocouplers only really transmit digital signals, and [Giovanni Carrera] needed to measure an analog voltage.


Enter the voltage-to-frequency IC that does just what it says: produces a square wave with a frequency that’s proportional to the voltage applied. Pass this square wave through an optocoupler, and you can hit one side with voltages approaching lightning strikes without damaging the microcontroller on the other side. And you’re still able to measure the voltage accurately by measuring the frequency on the digital I/O pins of the microcontroller.

[Giovanni] built up and documented a nice circuit. He even tested it for linearity. If you’re ever in the position of needing to measure a voltage in a non-traditional way, you’ll thank him later.

Your ESP8266 Needs More Memory

We just got through reviewing MicroPython on the ESP8266, and one of the main takehomes is that our ESP modules need more flash memory. You may be in the same boat — the earliest (and cheapest) modules on the market only had 512 kB of flash. For over-the-air programming, or to give you some more space for fancier programs, you’re going to want 1 MB or even 4 MB.

The solution? Just buy a new flash chip and solder it on. This is especially easy if you’ve got an ESP-01, ESP-03, or ESP-11 modules where the flash chip is exposed. Desolder, resolder, done. It can be a little trickier for those modules with a tin can around chips, but that’s nothing that a little hot air can’t fix. See the video embedded below for a good walk-through.

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