Pipe in (Robot) Hand

How do you make a robot hand? If you are [Robimek], you start with some plastic spiral tubing, some servo motors, and some fishing line. Oh, and you also need an old glove.

The spiral tubing (or pipe, if you prefer) is cut in a hand-like shape and fused together with adhesive. The knuckle joints are cut out to allow the tubing to flex at that point. The fishing line connects the fingertips to the servo motors.

The project uses an Arduino to drive the servos, although you could do the job with any microcontroller. Winding up the fishing line contracts the associated finger. Reeling it out lets the springy plastic pipe pull back to its original position.The glove covers the pipes and adds a realistic look to the hand.
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Making Dumb Robots Evolve

Evolution is a fact of life, except in Kansas. It is the defining characteristic of life itself, but that doesn’t mean a stupid robot can’t evolve. For his entry into the Hackaday Pi Zero contest, [diemastermonkey] is doing just that: evolution for robots built around microcontrollers and a Raspberry Pi.

[diemastermonkey]’s project is a physical extension to genetic algorithms. Just like DNA and proteins have no idea what they’re actually doing, microcontrollers don’t either. Instead of randomly switching up base pairs and amino acids, [diemastermonkey]’s project makes random connections pins depending on the values of those pins.

The potential of these crappy, randomly programmed robots is only as good as the fitness function, and so far [diemastermonkey] has seen some surprising success. When putting these algorithms into a microcontroller connected to a tilting table mechanism and a PIR sensor, the robot eventually settled on a bit of code that would keep a ball in motion. You can check out the video of that below.


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The Raspberry Pi Zero contest is presented by Hackaday and Adafruit. Prizes include Raspberry Pi Zeros from Adafruit and gift cards to The Hackaday Store!
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Petite Package Provides Powerful Robot

The Robot Operating System (ROS) is typically associated with big robots but [Grassjelly] decided to prove differently by creating Linorobot. This small, differential drive robot is similar in appearance to many small Arduino based robots often used for line following. Linorobot packs a lot more computing power with a Teensy 3.1 connected to a Radxa Rock Pro. The Teensy handles the motors, reading their encoders, and acquisition of IMU data.

The Radxa, new to us here at Hackaday, is a single board computer based on the quad-core ARM Cortex-A9 1.6 GHz CPU. It may not have been seen on our pages but if you’re at Hackaday Belgrade you can attend a session on building a cluster using it. The ability to run Linux is key to using ROS, which is an open source system for controlling robots. With the Radxa running ROS it interfaces directly to the Neato XV-11 Lidar’s dedicated controller board.

The Linorobot packs into a small robot the capabilities usually seen in much larger and expensive robots such as the Turtlebot 2. With this diminutive robot hackers can learn about doing SLAM (Simultaneous Localization and Mapping) and autonomous navigation, plus the other capabilities of ROS.

[Grassjelly] has a tutorial on building the robot which is also a good introduce to ROS. He provides the software as open source. It’s an impressive project which provides a small, comparatively affordable robot for learning and working with ROS. A video of Linorobot SLAMing and navigating [Grassjelly’s] lab is after the break.

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Wall-E Goes Corporate, Offering Telepresence Service

I guess if you are going to build a robot to do something boring like telepresence, you might as well make it cute. That’s obviously what [Andrew Maurer] was thinking when he built a telepresence robot using a Wall-E toy. The result is kind of adorable: Wall-E is holding the 5-inch HDMI screen that shows the video, and can scoot around in true Pixar fashion under remote control.

It’s also a neat build on the inside, using a Raspberry Pi for the brains and an Adafruit MotorHat to control the motors. The original toy didn’t have motors, so he added a new RC gearbox and motors to drive the little fella around. Installed behind Wall-Es eye is a USB webcam. Running behind the scenes is a mumble server that does the audio, a copy of Chromium that shows the video, and an Apache server that feeds the captured video to the other end of the conversation. The whole thing is tied together by a few scripts that kick things off appropriately and allow the user to remotely control Wall-E. It’s a cute build, and hopefully Wall-E can still find his EVE while performing his new corporate duties.

[via reddit]

Tiny Open Source Robot

We watched the video introduction for this little open source robot, and while we’re not 100% sure we want tiny glowing eyes watching us while we sleep, it does seem to be a nice little platform for hacking. The robot is a side project of [Matthew], who’s studying for a degree in Information Science.

The robot has little actuated grippy arms for holding a cell phone in the front. When it’t not holding a cellphone it can use its two little ultrasonic senors to run around without bumping into things. We like the passive balancing used on the robot. Rather than having a complicated self-balancing set-up, the robot just uses little ball casters to provide the other righting points of contact.

The head of the robot has plenty of space for whatever flavor of Arduino you prefer. A few hours of 3D printing and some vitamins is all you need to have a little robot shadow lurking in your room. Video after the break.

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Fail of the Week: Battery Pack Jack Wired Backwards

Last Saturday I had a team of teenage hackers over to build Arduino line-following robots from a kit. Everything went well with the mechanical assembly and putting all the wires on the correct pins. The first test was to check that the motors were moving in the proper direction. I’d written an Arduino program to test this. The first boy’s robot worked fine except for swapping one set of motor leads. That was anticipated because you cannot be totally sure ahead of time which way the motors are going to run.

The motor’s on the second robot didn’t turn at all. As I checked the wiring I smelled the dreaded hot electronics smell but I didn’t see any smoke. I quickly pulled the battery jack from the Arduino and – WOW! – the wires were hot. That didn’t bode well. I checked and the batteries were in the right way. A comparison with another pack showed the wires going into the pack were positioned properly. I plugged in another pack but the motors still didn’t run.

I got my multimeter, checked the voltage on the jack, and it was -5.97 V from center connector to the barrel. The other pack read 6.2 V. I had a spare board and pack so swapped those and the robot worked fine. Clearly the reverse polarity had zapped the motor control ICs. After that everyone had a good time running the robots on a course I’d laid out and went home pleased with their robots.

After they left I used the ohmmeter to check the battery pack and found the wiring was backwards, as you can see in the feature photo. A close inspection showed the wire with a white line, typically indicating positive, indeed went to the positive battery terminal. I shaved the barrel connector down to the wires and the white line wire was connected to the outside of the barrel. FAIL!

This is a particularly bad fail on the part of the battery pack supplier because how hard is it to mess up two wires? You can’t really fault the robot kit vendor because who would expect a battery pack to be bad? The vendor is sending me a new battery pack and board so I’m satisfied. Why did I have an extra board and pack, actually an entire kit? For this exact reason; something was bound to go wrong. Although what I had imagined was for one of the students to break a mechanical part or change wiring and zap something. Instead, we were faced with a self-destructing kit. Prudence paid off.

Connect Four Robot Uses Raspberry Pi

Most people play games for entertainment. Hackers build robots to play games for entertainment. That’s what [piandchips] did. He used a Raspberry Pi and a MeArm kit to build a Connect 4-playing robot. The robot–named 4-Bot–has to do two things: the first is it has to be able to manipulate the pieces. Secondly, it has to be able to see the board. The MeArm imbues 4-Bot with the manipulation ability, and a clever scanning system does the trick.

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