Author: Danie Conradie

426 Articles

Three-Stage Thrust Vectoring Model Rocket With Tiny Flight Computers

September 5, 2021 by 23 Comments

Flying a thrust-vectoring rocket can be a challenge, and even more so if you stack multiple stages and a minimalist flight computer on top of it all. But [Joe Barnard] is not one to shy away from such a challenge, so he built a three stage actively guided rocket named Shreeek.

[Joe] is well known for his thrust-vectoring rockets, some of which have came within a hair’s breadth of making a perfect powered landing. Previous rockets have used larger, more complex flight computers, but for this round, he wanted to go as small and minimalist as possible. Each stage of the rocket has its own tiny 16 x 17 mm flight computer and battery. The main components are a SAM21 microcontroller running Arduino firmware, an IMU for altitude and orientation sensing, and a FET to trigger the rocket motor igniter. It also has servo outputs for thrust vector control (TVC), and motor control output for the reaction wheel on the third stage for roll control. To keep it simple he omitted a way to log flight data, a decision he later regretted. Shreeek did not have a dedicated recovery system on any of the stages, instead relying on its light weight and high drag to land intact

None of the four launch attempts went as planned, with only the first two stages functioning correctly in the test with the best results. Thanks to the lack of recorded flight data, [Joe] had to rely on video footage alone to diagnose the problems after each launch. Even so, his experience diagnosing problems certainly proved its worth, with definitive improvements. However, we suspect that all his future flight computers will have data logging features included.

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Giving A Console Controller Mouse-Like Precision Aim

September 4, 2021 by 23 Comments

Controller vs keyboard and mouse is one of the never-ending battles in the world of gaming, with diehard proponents on both sides of the fence. [Tech Yesterday] has been working to create a controller that’s the best of both worlds. His latest Mouse Pro Controller V5 features an inverted mouse riding on ball bearings.

Mouse Pro Controller V1-3‘s main focus was to create the largest possible moving surface for an optical thumb mouse for precision aiming. However, [Tech Yesterday] found that one’s thumb doesn’t work well for traversing a large flat surface, but works better with a concave surface. On V4 he flipped the optical sensor around, embedding it in the controller, with a small circular “mouse pad” attached to his thumb. The concave surface was made from the diffuser of a large LED light bulb. It had slightly too much friction for [Tech Yesterday]’s liking, so he embedded an array of small ball bearings in the surface using magnets.

While this “thumb mouse” has excellent precision, it can be a bit slow when you need to make large movements, like when performing 360° no scopes for the clips. For these situations, [Tech Yesterday] embedded a thumb stick on the back of the controller to allow for fast sideways movements using his middle fingers.

[Tech Yesterday] is already working on V6, but feels close to the limit of his skills. If you are interested in working with him, be sure to get in touch! Modding controllers for fun and performance are great, but for gamers with prosthetic fingers it’s a requirement.

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Animatronic Puppetry Controller Skips Joystick Or Keyboard

September 4, 2021 by 2 Comments

One of the major challenges of animatronics is creating natural looking motion. You can build something with an actuator for every possible degree of freedom, but it will still be disappointing if you are unable to control it to smoothly play the part. [Mr. Volt] has developed a passion for animatronic projects, but found programming them tedious, and manual control with keyboard or controller difficult to do right. As an alternative, he is building Waldo, an electronic puppetry controller.

The Waldo rig is being developed in conjunction with [Mr. Volt]’s build of Wheatley, the talkative ball-shaped robot from the Portal 2 game. The puppetry rig consists of a series of rings for [Mr Volt]’s hand, with the position of each being read by angle sensors. This allows him to control Wheatley’s orientation of the body and eyeball, eyelids, and handles. Wheatley and Waldo both still need a few refinements, but we look forward to seeing the finished project in action.

The Portal games have inspired several featured projects, including GLaDOS, the turrets, and of course more Wheatly builds.

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Smooth Servo Motion For Lifelike Animatronics

September 3, 2021 by 10 Comments

Building an animatronic robot is one thing, but animating it in a lifelike fashion is a completely different challenge. Hobby servos are cheap and popular for animatronics, but just letting it move at max speed isn’t particularly lifelike. In the video after the break, [James Bruton] demonstrates how to achieve natural motion with a simple animatronic head and a few extra lines of code.

Very little natural body movement happens at a constant speed, it’s always accelerating or decelerating. When we move our heads to look at something around us, our neck muscles accelerate our head sharply in the chosen direction and then slows down gradually as it reaches its endpoint. To do this in Arduino/C code, a new intermediate position for the servo is specified for each main loop until it reaches the final position. The intermediate value is the sum of 95% of the current position, and 5% of the target position. This gives the effect of the natural motion described above. The ratios can be changed to suit the desired speed.

The delay function is usually one of the first timing mechanisms that new Arduino programmers learn about, but it’s not suited for this application, especially when you’re controlling multiple servos simultaneously. Instead, the millis function is used to keep track of the system clock in the main loop, which fires the position update commands at the specified intervals. Adafruit wrote an excellent tutorial on this method of multitasking, which [James] based his code on. Of course, this should be old news to anyone who has been doing embedded programming for a while, but it’s an excellent introduction for newcomers.

Like most of [James]’s projects, all the code and CAD files are open source and available on GitHub. His projects make regular appearances here on Hackaday, like his mono-wheel balancing robot and mechanically multiplexed flip-dot display.

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Coaxcopter To Carry Man

September 3, 2021 by 14 Comments

One of the major perks of all the affordable flight controllers and motors available from the hobby market is that you can really experiment with some crazy aircraft designs. [amazingdiyprojects] is experimenting with a coaxial helicopter design, with the goal off possibly using for a manned version in the future. (Video link, embedded below.)

The aircraft uses a pair of coaxial counter-rotating motors with large propellers, with several redundant control surfaces below the propellers. One of the theoretical advantages of this arrangement, compared to the more conventional quadcopter type designs, is redundancy. While a quadcopter will start tumbling when a single motor fails, this design will still be able to descend safely with just one motor.

It is also not dependent on the main motors for yaw, pitch and roll control. In multirotors, the motors need to keep a significant amount of the motor’s available power in reserve to increase torque at a moment’s notice for attitude control. This craft can use all the available thrust from the motors for lift, since control is provided by the control surfaces. There are five sets of redundant control surfaces below the propellers, each set connected to a separate flight controller.

Another advantage of this design is efficient for a given footprint, since one large propeller will always be more efficient than multiple smaller propellers. One of the goals for [amazingdiyprojects] is to fit the full size craft in a shipping container or on a trailer for transport without dissasembly.

[amazingdiyprojects] has built manned drones before, using both electric motors and internal combustion engines. And don’t miss the most gonzo wind tunnel ever at 7:00 in the video below. Continue reading “Coaxcopter To Carry Man” →

Extending bicycles can lift it's rider a meter into the air on four pneumatic pistons

Extending Bicycle Will Let You Stand Out Above The Crowd

September 2, 2021 by 10 Comments

Some bicycles are built primarily for practicality, while others are more focused on novel looks. [Make It Extreme]’s latest project, the extending bicycle, falls squarely in the latter category.

Built around four custom-machined pneumatic pistons, this electric bike can lift the rider about a meter into the air with the flick of a switch. The front pair forms the bicycle’s forks, while the rear pair is mounted between the frame and swingarm. A small onboard compressor is used to charge a pair of modified fire extinguishers, which feed the pistons via pneumatic valves mounted on the handlebars. The wheels and brakes were scavenged from an old scooter. Since the length between the crankset and rear wheel never changes, there is no need to struggle with chain tensioners as the ride height changes.

While we would hate to face-plant from that height, it certainly looks like a fun ride and conversation starter. This is the case for many of [Make It Extreme]’s projects, like a ridable tank track and monowheel motorcycle.

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One Wood Ring To Rule Them All

August 31, 2021 by 3 Comments

[Olivier Gomis] did not have access to the fires of Mount Doom to forge a large replica of the One Ring, so he had to settle for patience, maple, and a wood lathe. It does have the added convenience of not needing to fire to expose its true nature, just angry pixies from a wall socket.

[Olivier] made the ring in separate inner and outer sections from 72 blocks of maple. The blocks were glued together in 12-sided rings, and stacked in layers to achieve the desired width. The surfaces were cut smooth and thinned out on a wood lathe, and an internal channel was created for LED strips. The Black Speech was cut through the walls of both the inner and outer surfaces using a manual router. Using the ring itself as a former, he made a wooden base for the router to allow it to slide across the surface without wobbling.

The inside wall was cut into sections and glued into a recess in the external portion. The inscriptions were covered with a maple veneer, which still allows it to be visible when the internal LEDs are switched on. The wiring runs from the base of the stand through an S-shaped stem that was made from layers of veneer clamped in a former. A total of 53 hours of painstaking effort went into this work of art, but the end product would make any hardcore Lord of the Rings fan envious.

For more LOTR-themed hacks, check out the secret door to the Mines of Moria secret door, and a sword that glow blue in the presence of unsecured WiFi.

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