Would you use your tech prowess to cheat at the Pinewood Derby? When your kid brings home that minimalist kit and expects you to help engineer a car that can beat all the others in the gravity-powered race, the temptation is there. But luckily, there are some events that don’t include the kiddies and the need for parents to assume the proper moral posture. When the whole point of the Pinewood Derby is to cheat, then you pull out all the stops, and you might try building an electrodynamic suspension hoverboard car.
Fortunately for [ch00ftech], the team-building Derby sponsored by his employer is a little looser with the rules than the usual event. Loose enough perhaps to try a magnetically levitating car. The aluminum track provided a perfect surface to leverage Lenz’s Law. [ch00ftech] tried different arrangements of coils and drivers in an attempt to at least reduce the friction between car and track, if not outright levitate it. Sadly, time ran out and physics had others ideas, so [ch00ftech], intent on cheating by any means, tried spoofing the track timing system with a ridiculous front bumper of IR LEDs. But even that didn’t work in the end, and poor [ch00f]’s car wound up in sixth place.
So what could [ch00ftech] had done better? Was he on the right course with levitation? Or was spoofing the sensors likely to have worked with better optics? Or should he have resorted to jet propulsion or a propeller drive? How would you cheat at the Pinewood Derby?
Fail of the Week is a Hackaday column which celebrates failure as a learning tool. Help keep the fun rolling by writing about your own failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.
This Raspberry Pi 2 with computer vision and two solenoid “fingers” was getting absurdly high scores on a mobile game as of late 2015, but only recently has [Kristian] finished fleshing the project out with detailed documentation.
Developed for a course in image analysis and computer vision, this project wasn’t really about cheating at a mobile game. It wasn’t even about a robotic interface to a smartphone screen; it was a platform for developing and demonstrating the image analysis theory he was learning, and the computer vision portion is no hack job. OpenCV was used as a foundation for accessing the camera, but none of the built-in filters are used. All of the image analysis is implemented from scratch.
The game is a simple. Humans and zombies move downward in two columns. Zombies (green) should get a screen tap but not humans. The Raspberry Pi camera takes pictures of the smartphone’s screen, to which a HSV filter is applied to filter out everything except green objects (zombies). That alone would be enough to get you some basic results, but not nearly good enough to be truly reliable and repeatable. Therefore, after picking out the green objects comes a whole chain of additional filtering. The details of that are covered on [Kristian]’s blog post, but the final report for the project (PDF) is where the real detail is.
If you’re interested mainly in seeing a machine pound out flawless victories, the video below shows everything running smoothly. The pounding sounds make it seem like the screen is taking a lot of abuse, but [Kristian] mentions that’s actually noise from the solenoids and not a product of them battling the touchscreen. This setup can be easily adapted to test out apps on different models of phones — something that has historically cost quite a bit of dough.
If you’re interested in the nitty-gritty details of the reasons and methods used for the computer vision portions, be sure to go through [Kristian]’s github repository where everything about the project lives (including the aforementioned final report.)
Continue reading “Abusing a Cellphone Screen with Solenoids Posts High Score”
Pokemon Go has done a great service to the world health. Or would’ve done, if we wouldn’t hack it all the time. The game suggests, you breed Pokemon eggs by walking them around, but [DannyMcMurray] has a better idea: Strapping your smartphone to the propeller of a fan and taking them for spin that way.
Continue reading “Pokemon Go Egg Incubator Takes Your Eggs For A Spin”
Blood doping is so last decade! The modern cyclist has a motor and power supply hidden inside the bike’s frame.
We were first tipped off to the subject in this article in the New York Times. A Belgian cyclocross rider, Femke Van den Driessche, was caught with a motor hidden in her bike.
While we don’t condone sports cheating, we think that hiding a motor inside a standard bike is pretty cool. But it’s even more fun to think of how to catch the cheats. The Italian and French press have fixated on the idea of using thermal cameras to detect the heat. (Skip to 7:50 in the franceTVsport clip.) We suspect it’s because their reporters recently bought Flir cameras and are trying to justify the expense.
The UCI, cycling’s regulatory body, doesn’t like thermal. They instead use magnetic pulses and listen for the characteristic ringing of a motor coil inside the frame. Other possibilities include X-ray and ultrasonic testing. What do you think? How would you detect a motor inside a bike frame or gearset?
[Ben Krasnow’s] latest project will be good for anyone who wants a complicated way to cheat on a test. He’s managed to squeeze a tiny FM radio receiver into a ballpoint pen. He also built his own bone conduction microphone to make covert listening possible. The FM radio receiver is nothing too special. It’s just an off the shelf receiver that is small enough to fit into a fatter pen. The real trick is to figure out a way to listen to the radio in a way that others won’t notice. That’s where the bone conduction microphone comes in.
A normal speaker will vibrate, changing the air pressure around us. When those changes reach our ear drums, we hear sound. A bone conduction mic takes another approach. This type of microphone must be pressed up against a bone in your skull, in this case the teeth. The speaker then vibrates against the jaw and radiates up to the cochlea in the ear. The result is a speaker that is extremely quiet unless it is pressed against your face.
Building the bone conduction mic was pretty simple. [Ben] started with a typical disk-shaped piezoelectric transducer. These devices expand and contract when an alternating current is passed through them at a high enough voltage. He cut the disk into a rectangular shape so that it would fit inside of the clicker on the ballpoint pen. He then encased it in a cylinder of epoxy.
The transducer requires a much higher voltage audio signal than the litter radio normally puts out. To remedy this problem, [Ben] wired up a small impedance matching transformer to increase the voltage. With everything in place, all [Ben] has to do to listen to the radio is chew on the end of his pen. While this technology might help a cheater pass an exam, [Ben] also notes that a less nefarious use of this technology might be to place the speaker inside of the mouthpiece of a CamelBak. This would allow a hiker to listen to music without blocking out the surrounding noise. Continue reading “Turning an Ordinary Pen into a Covert Radio Receiver”
Don’t mind me, I’m just listening to some tunes during our poker game. Well, that and getting some electronic coaching about poker odds. This board lets you wiggle your toes to input the upcards, and those in your hand. After each entry the gadget will tell you your odds of winning the hand. Take it easy with this kind of stuff, if Rounders was at all realistic, getting caught cheating is a painful mistake.
The thing we find interesting about the system is that it doesn’t use a stored odds database. Instead, the Propeller chip runs a simulation of 1000 hands of poker based on the cards you have entered and uses the results to calculate the odds. [Nick] says that this runs quickly because he’s using multiple cores for the calculations, and it cuts down on the data that the device needs to have on board. Right now the feedback uses a text-to-speech generated voice, but you can customize the audio clips if you’d like. Check out a demo of the device in the clip after the break.
Not looking to get the beat down for cheating? Here’s a poker tournament timer that we assure you is on the up-and-up. Continue reading “Board lets you know when to hold ’em; know when to fold ’em”
[Alex Papadimoulis] wrote about ingenuity and hacking in high school. Immediately after the teacher’s installed a new electronic note taking and test giving software, the students began hacking. They managed to find several ways to ace their tests, none of which involved studying hard the night before. Ultimately, the teachers went back to the old system to prevent such shenanigans.