There comes a moment when our project sees the light of day, publicly presented to people who are curious to see the results of all our hard work, only for it to fail in a spectacularly embarrassing way. This is the dreaded “Demo Curse” and it recently befell the SIT Acronis Autonomous team. Their Roborace car gained social media infamy as it was seen launching off the starting line and immediately into a wall. A team member explained what happened.
A few explanations had started circulating, but only in the vague terms of a “steering lock” without much technical detail until this emerged. Steering lock? You mean like The Club? Well, sort of. While there was no steering wheel immobilization steel bar on the car, a software equivalent did take hold within the car’s systems. During initialization, while a human driver was at the controls, one of the modules sent out NaN (Not a Number) instead of a valid numeric value. This was never seen in testing, and it wreaked havoc at the worst possible time.
A module whose job was to ensure numbers stay within expected bounds said “not a number, not my problem!” That NaN value propagated through to the vehicle’s CAN data bus, which didn’t define the handling of NaN so it was arbitrarily translated into a very large number causing further problems. This cascade of events resulted in a steering control system locked to full right before the algorithm was given permission to start driving. It desperately tried to steer the car back on course, without effect, for the few short seconds until it met the wall.
While embarrassing and not the kind of publicity the Schaffhausen Institute of Technology or their sponsor Acronis was hoping for, the team dug through logs to understand what happened and taught their car to handle NaN properly. Driving a backup car, round two went very well and the team took second place. So they had a happy ending after all. Congratulations! We’re very happy this problem was found and fixed on a closed track and not on public roads.
Some of us have computer mice with more buttons than we have fingers, resolution tracking finer than a naked eye can discern, and forced-air vents. All these features presuppose one thing; the user has a functioning hand. [Federico Runco] knows that amyotrophic lateral sclerosis, ALS, or Lou Gehrig’s disease, will rob a person of their ability to use standard computer inputs, or the joystick on a motorized wheelchair. He is building EyesDrive for the 2020 Hackaday Prize, to restore that mobility to ALS patients. There are already some solutions, but this one focuses on a short bill of materials.
Existing systems are expensive and often track pupil location, which returns precise data, but EyesDrive only discerns, left, right, and resting. For these, we need three non-invasive electrodes, a custom circuit board with amplifiers, signal processing circuits, and a microcontroller. He includes a Bluetooth socket on the custom PCBs, which is the primary communication method. In the video below he steers a virtual kart around a knotty course to prove that his system is up to the task of an urban wheelchair.
EyesDrive by [Federico Runco] should not be confused with the HackadayPrize2015 winner, Eyedrivomatic, lead by two remarkable hackers, Steve Evans and Patrick Joyce.
Continue reading “Karting Hands-Free”
First Person View (or First Person Video) in RC refers to piloting a remote-controlled vehicle or aircraft via a video link, and while serious racers will mount the camera in whatever way offers the best advantage, it’s always fun to mount the camera where a miniature pilot’s head would be, and therefore obtain a more immersive view of the action. [SupermotoXL] is clearly a fan of this approach, and shared downloadable designs for 3D printed cockpit kits for a few models of RC cars, including a more generic assembly for use with other vehicles. The models provide a dash, steering wheel, and even allow for using a small servo to make the steering wheel’s motions match the actual control signals sent. The whole effect is improved further by adding another servo to allow the viewer to pan the camera around.
Check out the video embedded below to see it in action. There are more videos on the project’s page, and check out the project’s photo gallery for more detailed images of the builds.
Continue reading “Downloadable 3D Cockpits Enhance FPV Racing”
[Underling] sent in his bristlebot project that aims to put a new spin on controlling bristlebot movement. We have seen several attempts at bristlebot directional control in the past, but none of these methods really fit what he wanted to do. His goal was to use a single brush rather than two, and be able to aim the bot in any direction at will.
He tried several different designs, but settled on what you see in the picture above. The large brush head is fitted with a vibrating motor on the front as well as a cell phone battery near the midsection. These pieces are placed in the center plane of the brush as to not influence the direction of movement. A separate servo-like motor is placed on the back of the brush, and each side of the motor’s arm is attached to a paddle that extends down the sides of the brush. When the motor is activated, one paddle is pressed in towards the bristles, while the other paddle is pulled away. This causes an immediate shift in direction, and should provide for a relatively tight turn radius. It should be noted that he also took the time to remove bristles from the center of the brush where the steering paddles are located in order to improve turning performance.
Unfortunately [Underling] does not currently have a video camera with which to show off his work, but we hope to see some action footage in the near future.
This large bristlebot has no prolem steering itself by shifting its weight. It’s easy enough to watch the video after the break and see how this works. But there’s still the same air of “I can’t believe that actually works” which we experienced with the original bristlebot.
This is not the first attempt to calm a bristlebots movements, but we don’t remember seeing one you could drive around like an RC car. [Glajten] up-sized the bot with what appears to be a small shop broom cut in half, creating a catamaran design. The vibrating motor, which might have come out of a gaming controller, rides on the back of the bot, centered between the two bristle platforms. On the front a servo motor holds the shaft of a long bolt which has extra weight at the end of it. Steering happens when the weight is offset by a turn of the servo.
Continue reading “RC Bristlebot Shifts Weight For Steering”
[Dan Fruzzetti’s] daughter was delighted to get a motorized vehicle from her Grandparents, but [Dan] was unimpressed with the stock features. The lead-acid battery supplied remarkable life between charges, but the vehicle only had one feature: a go button that routed juice to the bipolar motor. After the break we’ll look at his improvements to the drive train, steering, and cosmetics.
Continue reading “Improving A Motorized Toy”