Sonar Built from Piezo and Microphone

[Jason] has continued to plug along with his sonar build and recently showed up a monostatic active sonar using a piezo element and microphone. Regular readers will remember [Jason’s] experiments from a Fail of the Week post which focused on his water-proofing woes from a much earlier prototype.

We find this offering far more engaging. He has ditched the ultrasonic module seen in those experiments. The new rig drives the piezo element using a 27V source. After each ping is sent out, the microphone input is immediately captured to detect the return of the audible sound. [Jason] mentions that the TI Launchpad he’s using for the project is fast enough for these experiments but he may switch to a Teensy 3.1 in order to double the RAM and thereby increase the sample size he is able to record.

Of course this is intended for underwater ROVs so his next iteration will involve a DIY hydrophone. We can’t wait to see that one as the process of converting this test rig into one that works underwater evades us. If you have some tips on that topic please let us know in the comments.

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ANUBIS, A Natural User Bot Interface System

[Matt], [Andrew], [Noah], and [Tim] have a pretty interesting build for their capstone project at Ohio Northern University. They’re using a Microsoft Kinect, and a Leap Motion to create a natural user interface for controlling humanoid robots.

The robot the team is using for this project is a tracked humanoid robot they’ve affectionately come to call Johnny Five.  Johnny takes commands from a computer, Kinect, and Leap motion to move the chassis, arm, and gripper around in a way that’s somewhat natural, and surely a lot easier than controlling a humanoid robot with a keyboard.

The team has also released all their software onto Github under an open source license. You can grab that over on the Gits, or take a look at some of the pics and videos from the Columbus Mini Maker Faire.

LVBots CES Open House: Tabletop Challenge and Clothes Bot

LVBots, a club for robot building enthusiasts in Las Vegas, held an open house the week of CES. This was the only trip [Sophi] and I took away from the conference halls of The Strip and it was a blast! The group holds meetings twice a month in a space provided by Pololu — a well-known robotics and electronics manufacturer headquartered just south of McCarran International Airport.

Before the formal part of the gathering started there were several builds being shown off. [Claire] and [Brian] recently participated in an AT&T sponsored hackathon. Their creation is a robotic closet. The system involves moving racks of clothing which are tracked by a smartphone app. Interesting features discussed for the software include monitoring when each garment was last worn, last washed, and if it is appropriate for current weather conditions. Dig into the code in their repo.

In other parts of the room a pair of line-following robots did their thing, and a couple of sumo-bots competed to push each other out of the ring. A large group was gathered around the projector watching videos of robots of all types, brainstorming about the difficult parts, how they were overcome, and how these methods may be applied to their own build. I can attest that hanging with a group of people who are trying to cue up the most amazing robot demonstrations makes for amazing viewing!

As the organized part of the meeting began I was delighted to hear about a standing challenge from the LVbots group. The Tabletop challenge has multiple phases that serve to encourage builders to start modestly and then iterate to achieve new goals:

Phase 0: bring a robot to LVBots
Phase 1: travel back and forth without falling off
Phase 2: find an object and push it off
Phase 3: push object into a goal

[Nathan Bryant] was one of the two robot builders trying out the challenge on this night. He built this hexapod from balsa wood and three servo motors and was testing Phase 1. The bot includes a sensor dangling out in front of the robot to detect then the table surface is no long below. At that point it backs up a few steps, turns in place, and proceeds in the opposite direction. [Nathan] mentions that he worked out all the movements in a spreadsheet and that future firmware upgrades will dramatically increase the speed at which the bot moves. We love the audible cadence of the bot which is easily observed in the video above. At one point a leg dangles over the edge and it looks like [Nathan] pushed the bot back but I don’t remember him actually touching it so I’m calling this a trick of camera angle.

One phase further in the Tabletop Challenge is [Joe Carson]. He exhibited a wheeled robot he’s been working on that includes a gripper arm on the front. The robot looks around the table for a predefined color, in this case provided by a highlighting marker. When found the bot approaches, grips, and then proceeds to move the marker over the void where it is dropped out of existence; at least from the robot’s point of view.

Twisted String Actuators

[Travis] tells us about a neat actuator concept that’s as old as dirt. It’s capable of lifting 7kg when powered by a pager motor, and the only real component is a piece of string.

The concept behind the twisted string actuator, as it’s known to academia, is as simple as putting a motor on one end of a piece of string, tying the other end off to a load, and putting a few twists in the string. It’s an amazingly simple concept that has been known and used for thousands of years: ballistas and bow-string fire starters use the same theory.

Although the concept of a twisted string actuator is intuitively known by anyone over the age of six, there aren’t many studies and even fewer projects that use this extremely high gear ratio, low power, and very cheap form of linear motion. A study from 2012 (PDF) put some empirical data behind this simple device. The takeaway from this study is that tension on the string doesn’t matter, and more strands or larger diameter strands means the actuator shrinks with a fewer number of turns. Fewer strands and smaller diameter strands take more turns to shrink to the same length.

As for useful applications of these twisted string actuators, there are a few projects that have used these systems in anthropomorphic hands and elbows. No surprise there, really; strings don’t take up much space, and they work just like muscles and tendons do in the human body.

Thanks [ar0cketman] for the link.

Jamming Robot will Destroy You at Beer Pong

DSC_0363Wandering the aisles of Eureka Park, the startup area of the Consumer Electronics Show, I spotted a mob of people and sauntered over to see what the excitement was all about. Peeking over this gentleman’s shoulder I realized he was getting spanked at Beer Pong… by a robot!

Those in the know will recognize that the bot has only 3 cups left and so the guy definitely was giving it run for its money. But the bot’s ability to swish the ball on nearly every throw accounts for the scoreboard which read Robot: 116, Humans: 11. Unlike the ping pong robot hoax from last March, we can vouch for this one being real!

If you’re trying to attract the geek demographic, this must be one of the best offerings ever shown at a trade show. Empire Robotics manufactures the VERSABALL gripper. We know this as a jamming gripper and have been looking at the tech progress for many years now. Looking back to this Cornell research video from 2010 we realize it is based on the white paper which [John Amend, PhD] co-authored. He’s now CTO and Co-Founder of the company and was one of the people running the booth. We love it when trade show booths are staffed by the engineers!

Join me after the break for a rundown of how the system works along with a video clip of it hitting the target.

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Robotically-Tuned Tube Radio

Dubbed the “Robot Radio” by [Brek], this clinking-&-clunking project merges three generations of hackers’ favorite technologies: robots, vacuum tubes, and microcontrollers. After the human inputs the desired radio frequency the machine chisels its way through the spectrum, trying its best to stay on target.

This build began its life as a junky old tube radio that [Brek] pulled out of a shed. The case was restored and then the hacking began. Inserted between the human and the radio, a PIC 16F628A keeps watch in both directions. On one side, the radio’s tank circuit is monitored to see what frequency the radio is currently playing. On the other, the human’s input sets a desired frequency. If the two do not match, the PIC tells a stepper motor to begin cranking a pair of gears until they do.

Another interesting feature is that as the tubes and other electronics warm up and change their values, the matching circuit will keep them in line. [Brek] shows this in the video by deliberately sabotaging the gears and seeing the robot adjust them back where they belong.

As an afterthought, the Robot Radio was supplemented with a module that adds 100khz to the signal so that the information from a nearby airport can be received.

[Brek] styled the whole machine up with some copper framing and other bits, similar to his spectacular atomic clock build we featured last month.

See the video of the radio tuning after the break.

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Santa’s Autonomous Helping Hands Let the Jolly ol’ Fellow Kick Back this Season

For those skeptical about the feasibility of Santa’s annual delivery schedule, here’s an autonomous piece of the puzzle that will bewilder even the most hard-hearted of non-believers.

The folks over at the Center of Excellence Cognitive Interaction Technology (CITEC) in Germany have whipped together a fantastic demo featuring Santa’s extra pair of helping hands. In the two-and-a-half minute video, the robot executes a suite of impressive autonomous stocking-stuffing maneuvers: from recognizing the open hole in the stocking, to grasping specific candies from the cluster of goodies available.

On the hardware-side, the arms appear to be a KUKA-variant, while on the software-side, the visualizations are being handled by the open source robot software ROS‘ RVIZ tool.

If some of the props in the video look familiar, you’ll find that the researchers at CITEC have already explored some stellar perception, classification, and grasping of related research topics. Who knew this pair of hands would be so jolly to clock some overtime this holiday season? The entire video is set to a crisp computer-voiced jingle that serves as a sneaky summary of their approach to this project.

Now, if only we could set these hands off to do our other dirty work….

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