Little Flash Charges In 40 Seconds Thanks To Super Capacitors

November 21, 2019 by Gerrit Coetzee 10 Comments

We’ve all committed the sin of making a little arduino robot and running it off AA batteries. Little Flash is better than that and runs off three 350 F capacitors.

In fact, that’s the entire mission of the robot. [Mike Rigsby] wants people to know there’s a better way. What’s really cool is that 10 A for 40 seconds lets the robot run for over 25 minutes!

The robot itself is really simple. The case is 3D printed with an eye towards simplicity. The brains are an Arduino nano and the primary input is a bump sensor. The robot runs around randomly, but avoids getting stuck with the classic reverse-and-turn on collision.

It’s cool to see how far these capacitors have come. We remember people wondering about these high priced specialty parts when they first dropped on the hobby scene, but they’re becoming more and more prevalent compared to other solutions such as coin-cells and solder tab lithium batteries for PCB power solutions.

This Arduino Keeps Its Eyes On You

November 13, 2019 by Al Williams 5 Comments

[Will] wanted to build some animatronic eyes that didn’t require high-precision 3D printing. He wound up with a forgiving design that uses an Arduino and six servo motors. You can see the video of the eyes moving around in the video below.

The bill of materials is pretty simple and features an Arduino, a driver board, and a joystick. The 3D printing parts are easy to print with no supports, and will work with PLA. Other than opening up holes there wasn’t much post-processing required, though he did sand the actual eyeballs which sounds painful.

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FitSocket Is A Portal To Better Prostheses

November 11, 2019 by Kristina Panos 17 Comments

Traditionally, sockets for prostheses are created by making a plaster cast of the limb being fitted, and are then sculpted in carbon fiber. It’s an expensive and time-consuming process, and what is supposed to be a customized socket often turns out to be an uncomfortable disappointment. Though prosthetists design these sockets specifically to take pressure off of the more rigid areas of tissue, this usually ends up putting more pressure on the softer areas, causing pain and discomfort.

An MIT team led by [Arthur Preton] wants to make prosthesis sockets more comfortable and better customized. They created FitSocket, a machine that assesses the rigidity of limb tissue. You can see it in motion after the break.

FitSocket is essentially a ring of 14 actuators that gently prod the limb and test how much pressure it takes to push in the tissue. By repeating this process over the entire limb, [Preton] can create a map that shows the varying degrees of stiffness or softness in the tissue.

We love to see advancements in prostheses. Here’s an electronic skin that brings feeling to artificial fingertips.

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Sensing, Connected, Utility Transport Taxi For Level Environments

November 9, 2019 by Anool Mahidharia 3 Comments

If that sounds like a mouthful, just call it SCUTTLE – the open-source mobile robot designed at Texas A&M University. SCUTTLE is a low cost (under $350) robot designed for teaching Aggies at the Multidisciplinary Engineering Technology (MXET) program, where it is used for in-lab lessons and semester projects for the MXET 300 – Mobile Robotics undergraduate course. Since it is designed for academic purposes, the robot is very well documented, making it easy to replicate when you follow the instructions. In fact, the team is looking for others to build SCUTTLE’s and give them feedback in order to improve its design.

Available on the SCUTTLE website are a large collection of videos to walk you through fabrication, electronics setup, robot assembly, programming, and robot operation. They are designed to help students build and operate the mobile robot within one semester. Most of the mechanical and electronics parts needed for the robot are off-the-shelf and easy to procure and the rest of the custom parts can be easily 3D printed. Its modular design allows you the freedom to try different options, features and upgrades. SCUTTLE is powerful enough to carry a payload up to 9 kg (20 pounds) allowing additional hardware to be added. To keep cost low and construction easy, the robot uses a simple, two wheel drive system, using a pair of geared motors. This forces the robot to literally scuttle in a “non-holonomic” fashion to move from origin to destination in a sequence of left / right turns and forward moves, so motion planning is interestingly tricky.

The SCUTTLE robot is programmed using Python3 running under Linux and has been tested working on either a BeagleBone Blue or a Raspberry Pi. The SCUTTLE software guide is a good place to get acquainted with the system architecture.

The standard configuration uses ultrasonic sensors for collision avoidance, a standard USB camera for vision, and encoders coupled to the wheel drive pulleys for determining position with respect to the starting origin. An optional USB LiDAR can be added for area mapping. The additional payload capability allows adding on extra sensors, actuators or battery packs.

To complement information on the website, additional resources are posted on GitHub, GrabCAD and YouTube. Building a SCUTTLE robot ought to be a great group project at maker spaces wanting to get hackers started with Robotics. We have covered many Educational Robot projects in the past, but the SCUTTLE really shines with its ability to carry a pretty decent payload at a low cost.

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Making A Robotic Dog Better By Adding Springiness Without Springs

November 8, 2019 by Danie Conradie 5 Comments

Getting a legged robot to stay upright, especially a quadruped or biped, can be a challenging undertaking. To experiment with different approaches, [James Bruton] built robot dog test platform and is playing with “dynamic compliant simulated springs“, or in other words, using the motors to act as though they were springs and dampers..

When robotic legs are kept stiff, they tend to reduce the stability of the platform due to the sudden erratic movements of the robot, especially on uneven surfaces. With a back drivable joint arrangement, [James] is using limited holding current on the motor, and the position of the motor shaft is monitored using an encoder. When a leg experiences a resisting force, with will have some “give” and then the motor will return it to it’s intended position more slowly. Using a IMU on top of the robot, it can detect when it start leaning to a side, and then temporarily soften the other side to balance the robot.

This is quite a common technique in legged robots, but [James] does an excellent job of explaining just how it works. He hopes to use the lessons learned from the test platform to improve or redesign his already impressive OpenDog.

We’ve seen a number of quadruped robots on Hackaday recently. Including Boston Dynamics’ very expensive Spot as well as a low cost robot dog that giving its big brothers a run for their money, and doing some back flips in the process. Check out James’ video after the break. Continue reading “Making A Robotic Dog Better By Adding Springiness Without Springs” →

Bobble-Bot Teaches Modern Real-Time Robot Control

November 7, 2019 by Gerrit Coetzee 7 Comments

Bobble-Bot uses the standard inverted pendulum problem to teach modern robotic control using a Raspberry Pi, RT-Linux, and ROS.

We’re really impressed by the polish and design effort put into this project, and it’s no surprise that it’s a finalist in the 2019 Hackaday Prize. Bobble-Bot is a top heavy bot sitting on two BLDC motors. The brains of the operation is a Raspberry Pi running real-time Linux and ROS. This allows the robot to respond in a predictable manner to its inputs, and also allows for more control over thread priority than a regular kernel. In the past we’ve seen these inverted pendulum bots mostly being run on micro-controllers for just this reason, so it’s cool to see it make the jump to Linux.

Mechanically the bot can be printed on any consumer grade printer and assembled. We really appreciate the small details like making sure one screw size could be used to assemble the entire bot, eliminating the need for multiple tools.

They also have a simulator, and the bot’s software was built inside of that. It was a big moment when the real-world behavior finally matched the simulated performance. In fact, if you’re interested in the Bobble-Bot, you can try it out in simulation before committing to building the whole thing.

This project seems like a fun build for any hacker. We would have loved to have a project as polished and up-to-date as this one when we were learning controls in university. Video introducing it after the break.

Robotics Controller For The Pi Boasts An Impressive Feature List

November 5, 2019 by Donald Papp 4 Comments

[Michael Horne] recently shared his thoughts on the RedBoard+, a motor controller board for the Raspberry Pi aimed at robotic applications. His short version for busy people is: if you’re at all into robotics, get one because it’s fantastic.

At heart the RedBoard+ is a motor controller, but it’s packed with I/O and features that set it above the usual fare. It can drive two DC motors and up to twelve servos, but what is extra useful is the wide input range of 7-24 V and its ability to power and control the underlying Raspberry Pi. A user-programmable button defaults to either doing a reboot or safe shutdown, depending on how long the button is held. Another neat feature is the ability to blink out the IP address of the Pi using the onboard RGB LED, which is always handy in a pinch.

The RedBoard+ has a GitHub repository which provides a variety of test scripts and an easy to use library, as well as a variety of hookup guides and quickstart guides. There’s even a pre-configured SD image for those who prefer to simply dive in.

A brief demo video showing the board in operation is embedded below. If you’re interested in one, Creator [Neil] of RedRobotics has made it available for sale on Tindie.

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