Ask Hackaday: Fixing Your Tractor Could Land You Behind Bars

May 12, 2015 by Will Sweatman 225 Comments

It’s 9AM on any given Sunday. You can be found in your usual spot – knee-deep in wires and circuit boards. The neighbor’s barking dog doesn’t grab your attention as you pry the cover off of a cell phone, but the rustling of leaves by the back door does. Seconds later, several heavily armed SWAT officers bust in and storm your garage. You don’t have time to think as they throw your down on the cold, hard concrete floor. You’re gripped by a sharp stinging pain as one of the officers puts his knee in the square of your back. Seconds later, you’re back on your feet being lead to the back of an awaiting police cruiser. You catch the gaze of one of your neighbors and wonder what they might be thinking as your inner voice squeaks: “What did I do wrong?”

The answer to this question would come soon enough. Your crime – hacking your dad’s tractor.

“That’s like saying locking up books will inspire kids to be innovative writers, because they won’t be tempted to copy passages from a Hemingway novel.”

-Kyle Wiens

John Deere is trying to convince the Copyright Office that farmers don’t really own the tractors they buy from them. They argue that the computer code that runs the systems is not for sale, and that purchasers of the hardware are simply receiving “an implied license for the life of the vehicle to operate the vehicle.”

In order to modify or “hack” any type of software, you have to copy it first. Companies don’t like the copying thing, so many put locks in place to prevent this. But because hackers are hackers, we can easily get past their childish attempts to keep code and information out of our hands. So now they want to make it illegal. John Deere is arguing that if it is legal for hackers to copy and modify their software, that it could lead to farmers listening to pirated music while plowing a corn field. No I am not making this up — dig into this 25-page facepalm-fest (PDF) written by John Deere and you’ll be just as outraged.

Trying to keep hackers out using the DMCA act is not new. Many companies argue that locking hackers out helps to spur innovation. When in fact the opposite is true. What about 3D printers, drones, VR headsets…all from us! The Copyright Office, after holding a hearing and reading comments, will make a decision in July on whether John Deere’s argument has any merit.

Let us know what you think about all this. Can hackers and the free market learn to live in harmony? We just want to fix our tractor!

Thanks to [Malachi] for the tip!

PicoRico Hacks String Encoder For Bike Suspension Telemetry

May 12, 2015 by Mike Szczys 26 Comments

It’s simple, it’s elegant, and it works really really well. The PicoRico team built a telemetry system for a downhill bike. Off the top of your head how would you do this? Well, telemetry is easy… just add an IMU board and you’re golden. They went beyond that and have plans to go much further. In fact, the IMU was an afterthought. The gem of this build is a sensor that may go by several names: string encoder, draw wire sensor, stringpot, etc. But two things are for sure, they planned well for their hackathon build and they executed on that plan. This landed them as first-runners-up for the top award at the 2015 Disrupt Hackathon in New York, and the winners of the top Hackaday award at the event.

[Chris], [Marek], and [Dorian] wanted to log all the telemetry data from [Chris’] downhill bike. One of the biggest challenges is to measure the force absorbed by the suspension on the front fork. The three had seen a few attempts at this before. Those used a retractable wire like what holds keys to a custodian’s belt, mated with a potentiometer to measure the change. This is where the term stringpot comes from. The problem is that your resolution and sensitivity aren’t very reliable with this setup.

That is a sensor problem, not a mechanical problem so they kept the retractable reel and replaced the pot with a much more reliable part. In its place an AMT203 absolute position sensor provides an epic level of sensing. According to the datasheet (PDF) this SPI device senses 12 bits of rotation data, can be zeroed over the SPI bus, and is accurate to 0.2 degrees. Unfortunately we didn’t get a good up-close shot of the installation but it is shown in the video. The encoder and retractor mount above the shocks, with the string stretching down to the skewer. When the shocks actuate, the string extends and retracts, turning the absolute encoder. Combine this with the IMU (and two other IMUs they plan to add) and you’ve got a mountain of data to plot and analyze. The videos after the break show a demo of the string encoder and an interview with the team.

They came to play

It’s worth noting that the PicoRico team were in this to win it. They packed heavy for the 20-hour hackathon. Here’s a picture of all the gear they brought along with them to the event… in addition to the bike itself.

We see a solder station, Dremel (with drill press), impact driver, tap and die set, extension cords, boxes full of electronics, and more. This type of planning breaks down barriers often faced at hardware hackathons. You can download a software library; you can’t download a tool or building material that nobody has with them. This is the same lesson we learned from [Kenji Larsen] who, as part of his mentoring at the event, brought a mobile fabrication facility in a roller bag.

If you start getting into hackathons, and we hope you will, keep this in mind. Brainstorm as much as you can leading up to the event, and bring your trusted gear along for the ride.

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Hackaday Prize Entry: Junkyard Fuel Cell

May 11, 2015 by Brian Benchoff 26 Comments

Modern hydrogen fuel cells are incredible pieces of engineering. While a simplistic diagram of a fuel cell is just a stream of hydrogen, an anode, cathode, and a bit of oxygen, this does’t convey the complexity of the most important part of the fuel cell – the proton exchange membrane.

The proton exchange membrane is the part of a fuel cell that takes in hydrogen, spits out electrons, and produces water. They can be made from platinum to expensive DuPont products, and if [Charlie]’s hypothesis is correct, stuff you can pull out of a junkyard.

The goal of [Charlie]’s Prize entry is to create a small, proof of concept fuel cell that’s safe, low cost, and very easy to build. Right now he’s focused on finding a cheap, readily available proton exchange membrane to make this build accessible to everyone.

A hydrogen fuel cell will of course have pressurized hydrogen in it, and [Charlie] is taking some steps to mitigate the risks of having his limbs blown off. His first real project update is about the safety considerations of working with hydrogen. He’ll be using a simple hydrogen gas sensor to measure for leaks and sound an alarm.

The 2015 Hackaday Prize is sponsored by:

Life Sized Lego Spaceship Parts

May 11, 2015 by Brian Benchoff 18 Comments

Ah, 1980s space Lego sets. You may think the pirate ship and castle sets are cooler, but you’re wrong, because spaceship. spaceship. spaceship.

These space Lego sets had some very interesting parts, with tiny two-by sloped pieces printed with Lego analogs of computers, monitors, phones, intercoms, speakers, control panels, and everything else that makes a voxellated spaceship fly to the moon. Now, these pieces are functional, and they’re nearly life-size.

[Love Hultén] took these fantastic parts, modeled them, and scaled them up to six times normal Lego dimensions. These blocks were then fitted with buttons, displays, the guts of an old telephone, and all the other accoutrements to make these bricks functional. Two computer blocks can be connected together, and it will play video games with a Lego-shaped controller. The intercom works, and the buttons on control panels can be used to turn on lights.

It should be noted the Lego family is more than just the small bricks that really hurt when you step on them. Duplo, the blocks made for children who would stuff Lego down their own throats, is twice the size of Lego. Quatro are blocks made for toddlers, and are twice the size of Duplo and four times the size of Lego. Since [Love] made blocks that are six times the size of normal Lego blocks, we’ll leave it up to the comments to determine what this class of blocks should be named.

Video below.

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Extracting Lightning Strikes From HD Video

May 11, 2015 by James Hobson 15 Comments

Lightning photography is a fine art. It requires a lot of patience, and until recently required some fancy gear. [Saulius Lukse] has always been fascinated by lightning storms. When he was a kid he used to shoot lightning with his dad’s old Zenit camera — It was rather challenging. Now he’s figured out a way to do it using a GoPro.

He films at 1080@60, which we admit, isn’t the greatest resolution, but we’re sure the next GoPro will be filming 4K60 next. This means you can just set up your GoPro outside during the storm, and let it do it what it does best — film video. Normally, you’d then have to edit the footage and extract each lightning frame. That could be a lot of work.

[Saulius] wrote a Python script using OpenCV instead. Basically, the OpenCV script spots the lightning and saves motion data to a CSV file by detecting fast changes in the image.

The result? All the lightning frames plucked out from the footage — and it only took an i7 processor about 8 minutes to analyze 15 minutes of HD footage. Not bad.

Now if you feel like this is still cheating, you could build a fancy automatic trigger for your DSLR instead…

Hacking Amazing Soldering Features Into The Already Great Weller WMRP

May 11, 2015 by Anool Mahidharia 35 Comments

Weller, the German soldering tools manufacturer, has a nice range of micro soldering irons (pencils) designated as the WMRP series. These are 12V, 40 W or 55W units with a 3 second heat up time, and allow quick tip exchange without needing any tools. [FlyGlas] built a neat soldering station / controller for the WMRP series based around an ATMega microcontroller running Arduino.

It’s packed with most of the features you see in a professional rig.

low offset op amp for soldering tip temperature measurement with type c thermocouple
cold junction compensation using the PTC (KTY82-210) included in the WMRP soldering pencil
input voltage measurement
soldering pencil current measurement
recognizing if the soldering pencil rests in the stand (–> standby)
3 buttons to save and recall temperature values
rotary encoder to set soldering temperature
illuminated 16×2 character LCD module
USB for debugging and firmware update
4mm safety socket for +12V power input and a protective earth socket for connection to ESD protection

A PWM signal from the microcontroller controls the load current using a MOSFET. Load current is measured using a Hall Effect-Based Linear Current Sensor – ACS712. The corresponding linear output voltage is buffered and slightly amplified using AD8552 zero drift, single supply, RRIO Dual Op Amp before being sent to the microcontroller ADC input. To ensure ADC measurements are accurate and stable, a low noise precision voltage reference – ADR392 is used. Another precision resistive voltage divider allows input voltage measurement. The supply input has over-current and reverse voltage protection. A set of buttons and a rotary encoder are connected to the microcontroller to allow settings and adjustments. An analog section measures the thermocouple voltage from the soldering pencil as well as the stand-by switch status. The handle has an embedded reed switch that is activated by a magnet in the support stand which puts it into stand-by mode. Another analog section performs cold junction compensation using the PTC sensor within the soldering pencil.

The Git repo contains the initial Arduino code which is still a work in progress. While the hardware source files are not available, the repo does have the pdf’s, gerbers and BOM list, if you want to take a shot at building it. Check a demo video after the break. Thanks [Martin] for sending in the tip.

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Makey Makey Made Smaller

May 11, 2015 by Brian Benchoff 17 Comments

When it launched in 2012, the Makey Makey was the golden child of the maker movement. It was a simple, easy to use board with holes for alligator clips and a USB socket that would present capacitive touch pads as a USB HID device. Thus, the banana piano was born.

The Makey Makey is a device specifically designed to introduce kids to electronics in a way the Arduino can’t match; even with an Arduino, most of the work is with code. If you’re introducing electronics to a class of 10-year-olds, that might be a bit too much.

Now there’s a new Makey Makey on the block. It’s the Makey Makey Go, and it’s the same user experience as the Makey Makey classic made cheaper and much more rugged.

The Makey Makey Go features a single touch pad to clamp an alligator clip to. That’s enough to send any keypress or a mouse click over USB, where a wide variety of apps and games can make this tiny thumb drive-sized board useful. Banana pianos are out, and plant harps and Jello Flappy Bird are in.

There aren’t many details about the internals of the Makey Makey Go, but [Jay] from Makey Makey says the prototypes are based on the ATMega32u4, while the production units will use cheaper chips. Video below.

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