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.

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.

VFC+calibration

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.

Continue reading “Your ESP8266 Needs More Memory”

Obsolescence As A Service

Yet another Internet of Things service has left its customers in the lurch. IoT devices (mostly lightbulbs) made sold by Greenwave Systems stopped talking to the outside world on July 1. More specifically, the server to which they all connected (ahem, “the cloud”) has been turned off, which rules out using the bulbs with Internet-based services like IFTTT, which was a major selling point of the Things in the first place.

[Edit: We were contacted by Greenwave, and they pointed out that they merely sold the IoT devices in question. They are made by TCP, which is also responsible for cancelling the service. And TCP has a history of doing this sort of thing before.]

It’s not the first time we’ve seen IoT companies renege on their promises to provide service, and it’s surely not going to be the last. We’re preaching to the choir here, but when even Google is willing to take the PR hit to effectively brick your devices, the only protection that you’ve got against obsolescence is an open protocol.

At least the users of Greenwave’s TCP’s devices will continue to be able to control them from within the home. That, plus some clever hacking, will make them workable into the future. But it’s not like the convenience that was sold with the devices.

Boo to shady IoT companies! But thanks to [Adrian] for the tip.

45-Year Old Nixie Calculator Turned UDP Server

In this beautiful and well-documented reverse engineering feat of strength, [Eric Cohen] reverse-engineered a 1971 Singer calculator to gain control of the fabulous Nixie tubes inside. Where a lesser hacker would have simply pulled the tubes out and put them in a more modern housing, [Eric] kept it all intact.

Not even content to gut the box and toss some modern brains inside, he snooped out the calculator’s internal wiring, interfaced a Raspberry Pi to it, and overrode the calculator’s (860 Hz) bus system. With the Pi on the inside, controlling the Nixie tubes, he did what any of us would do: set up a UDP server and write an Android app for his phone to push ASCII data over to the former calculator. When it’s not running in its default clock mode, naturally.

nixie-internals

All of this is extraordinarily well documented both on his website, in a slide presentation (PDF), and in video (embedded below). Our hats are tipped to the amazing attention to detail and fantastic documentation.

Now where is that Singer EC1117 calculator from 1971 that we’ve been saving for just such an occasion?

Continue reading “45-Year Old Nixie Calculator Turned UDP Server”

Two Great Radios Taste Great Together

[Johan Kanflo] sent us his latest recipe: a blend of one part RFM69 sub-gigahertz radio transceiver with one part ESP8266 module. The resulting dish looks absolutely delicious!

We’re all charmed with the ease of use that the ESP8266 brings to the table — plug it in and you’re talking to your existing WiFi network — but we hate the power consumption for battery-powered applications. WiFi is a power hog. And although ISM-band radio modules make point-to-point communications cheap and power-saving, getting them to talk with your computer takes an adapter.

So [Johan] combined the two radios and made a sweet ISM-radio-to-WiFi bridge. His demo application takes whatever data is sent over the ISM band and pushes it to an MQTT broker on his WiFi network. Hardware and firmware are up on GitHub.

We’ve been wanting a device like this for our home network for a while now. Kudos, [Johan] for making it so easy!

Government Drones To Toss M&Ms To Prarie Dogs

We hear a lot about drone surveillance, drone package delivery, drone this, and drone that. Honestly, though, the best use of drones has been taking cool aerial videos and posting them online. Until now.

The US Fish and Wildlife Service plans to cover acres upon acres of prairie-dog habitat with vaccine-laced, peanut-butter coated M&Ms. The snacks also include a dye that will show up in the whiskers of prairie dogs that take the bait, allowing scientists to assess the efficacy of the program. And this is all in the name of saving endangered black-footed ferrets which share burrows with the prairie dogs. It seems they were getting the plague from the prairie dogs.

The quads are outfitted with a “glorified gumball machine” that spreads the vaccine tidbits around. Why a quad? They can cover more space with less disruption to the animals’ habitat. That’s a great application in our book.

But if you think this is a case of the USF&WS showing outrageous innovation, consider the way rabies was all but eliminated in Europe: throwing hundreds of thousands of vaccine-doped chicken heads out of helicopters across France, Switzerland, and Germany. You couldn’t make this up.

(Via [Popular Science], where the title is even more clickbaity than ours. Get it? “Clickbait”?)

Headline image: US Fish and Wildlife Service Mountain-Prairie