RC Car Test Tether Takes Car Testing To New Lengths

It’s fascinating to see what happens when a creative hacker is given a set of constraints to work within. [rctestflight] found themselves in a very specific set of circumstances: Free RC cars from sponsors, and no real purpose for them. Instead of just taking them apart to see what made them tick (itself the past time of many a beginning hacker), [rctestflight] decided to let the RC cars disassemble themselves, destructively, on their way to 100,000 (scale) RC Car Miles, tallying up the distance (and the carnage) in the end as you see in the video below the break.

Can you spot the RC car under the mud?

Re-using a jig and test track (his backyard) from another test, [rctestflight] set up solar powered tether that could power any of the vehicles under test. The vehicles were modified as needed to drive along the circular track on a tether, and once stability was achieved, the cars were set on their own to either drive 100,000 scale miles or die trying.

Seeing as how [rctestflight] hales from the Pacific NorthWet of the United States near Seattle, the endurance test turned out to be not just a test of distance. Among the factors evaluated were how well each vehicle could withstand the mud, grime, and yes, even earthworms, that awaited them.

After each vehicle failed beyond the point of a quick fix, they were all torn down. Where each manufacturer cut corners could clearly be seen, and the weaknesses and strengths of each vehicle were pretty interesting. Plus, there’s a pretty great (awful) uh… rendition… of an iconic 80’s song. Twice. And of course the final conclusion: Exactly how many miles did each vehicle go before catastrophic failure? Check the video for results.

Regular readers will know that [rctestflight] is somewhat of a Hackaday regular, with plentiful great hacks such as this drone boat that sails the high seas of Lake Washington.

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Garage Distance Sensor Kicks Tennis Ball To Curb

Those with small garages might be familiar with the method of hanging a tennis ball from a ceiling to make sure they don’t hit the back wall with their car. If the car isn’t in the garage, though, the tennis ball dangling from a string tends to get in the way. To alleviate this problem, [asaucet] created a distance sensor that can tell him when his car is the perfect distance from the garage wall.

At the heart of the distance sensor is an HC-SR04 ultrasonic rangefinder and a PIC16F88 microcontroller. [asaucet] uses a set of four LEDs to alert the driver how close they are to the garage wall. [asaucet] also goes into great detail about how to use an LCD with this microcontroller for setting up the project, and the amount of detail should be enough to get anyone started on a similar project.

While this isn’t a new idea, the details that [asaucet] goes into in setting up the microcontroller, using the distance sensor, and using an LCD are definitely worth looking into. Even without this exact application in mind, you’re sure to find some helpful information on the project page.

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Amazing 3D-Scanner Teardown And Rebuild

0_10ea1b_776cdc71_origPour yourself a nice hot cup of tea, because [iliasam]’s latest work on a laser rangefinder (in Russian, translated here) is a long and interesting read. The shorter version is that he got his hands on a broken laser security scanner, nearly completely reverse-engineered it, got it working again, put it on a Roomba that was able to map out his apartment, and then re-designed it to become a tripod-mounted, full-room 3D scanner. Wow.

The scanner in question has a spinning mirror and a laser time-of-flight ranger, and is designed to shut down machinery when people enter a “no-go” region. As built, it returns ranges along a horizontal plane — it’s a 2D scanner. The conversion to a 3D scanner meant adding another axis, and to do this with sufficient precision required flipping the rig on its side, salvaging the fantastic bearings from a VHS machine, and driving it all with the surprisingly common A4988 stepper driver and an Arduino. A program on a PC reads in the data, and the stepper moves another 0.36 degrees. The results speak for themselves.

This isn’t [iliasam]’s first laser-rangefinder project, naturally. We’ve previously featured his homemade parallax-based ranger for use on a mobile robot, which is equally impressive. What amazes us most about these builds is the near-professional quality of the results pulled off on a shoestring budget.

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Vibrating Distance Torch Illuminates The Dark Without Light

If you’ve ever had to move around in a dark room before, you know how frustrating it can be. This is especially true if you are in an unfamiliar place. [Brian] has attempted to help solve this problem by building a vibrating distance sensor that is intuitive to use.

The main circuit is rather simple. An Arduino is hooked up to both an ultrasonic distance sensor and a vibrating motor. The distance sensor uses sound to determine the distance of an object by calculating how long it takes for an emitted sound to return to the sensor. The sensor uses sounds that are above the range of human hearing, so no one in the vicinity will hear it. The Arduino then vibrates a motor quickly if the object is very close, or slowly if it is far away. The whole circuit is powered by a 9V battery.

The real trick to this project is that the entire thing is housed inside of an old flashlight. [Brian] used OpenSCAD to design a custom plastic mount. This mount replaces the flashlight lens and allows the ultrasonic sensor to be secured to the front of the flashlight. The flashlight housing makes the device very intuitive to use. You simply point the flashlight in front of you and press the button. Instead of shining a bright light, the flashlight vibrates to let you know if the way ahead is clear. This way the user can more easily navigate around in the dark without the risk of being seen or waking up people in the area.

This reminds us of project Tacit, which used two of these ultrasonic sensors mounted on a fingerless glove.

A Simple Posture Sensor


If you are on the computer for a large part of the day, posture becomes a serious issue that can negatively impact your health. [Wingman] saw this problem, and created a hack to help solve it. His simple posture sensor will monitor the position of your head relative to the chair, and reminds you to sit up straight.

The posture sensor is built around the HC-SR04 ultrasonic distance sensor, an Attiny85, and a piezo speaker. We’ve seen this distance sensor used in the past for a few projects. Rather than going down the wearable route, which has its own drawbacks, [Wingman] decided to attach his sensor on the back of his chair. The best part is that the sensor is not mounted directly on the chair, but rather on a piece of fabric allowing it to be easily moved when needed.

Given how low-cost and small the sensor is, the project can be easily expanded by adding multiple sensors in different locations. This would allow the angle of the back and possibly the neck to be determined, giving a more accurate indicator of poor posture. There are very few hacks out there that address bad posture. Do you have a project that helps address bad posture? Have you used video processing or a wearable device to monitor your posture? Let us know in the comments an don’t forget to send post links about them to our tips line.

A Longboard Speed And Distance Computer


Why should cyclists have all of the fancy toys? Bicycle computers are very common these days but you won’t find similar hardware for skateboards and longboards. [KobraX22] isn’t taking it lying down. He built this speed and distance computer for his longboard. It doesn’t use very many components and should be easy to install.

The device monitors the rotation of one of the wheels by mounting a reflectance sensor on one of the trucks. It points toward the inside of a wheel which has a piece of black tape on it. Every time the tape passes it prevents the IR led from reflecting back at its paired receiver. This lets the Arduino count the revolutions, which are then paired with the wheel diameter to calculate speed as well as distance traveled. Of course the wheels wear down over time to so frequent riders will have to take new measurements at regular intervals.

[KobraX22] went with a QRB1114 sensor. It costs less than $2 and doesn’t require him to embed a magnet in the wheel like a hall effect sensor setup would have. It also shouldn’t interfere with any other fancy wheel hacks you’ve done, like adding a POV display.

[via Reddit]