PenguinBot Follows Light, Goes Screech in the Night

The Arduino Based Penguin Robot
Ever have one of those weekend projects that takes on a life of its own? [Michael] did, and the result is this PenguinBot. While [Michael's] wife was away for the weekend he happened upon a broken toy penguin. The batteries had leaked inside, destroying the contacts. Rather than bin the toy, [Michael] made it awesome by turning it into an autonomous robot. [Michael's] goal was to create a robot that could roam around the house avoiding obstacles, or follow a light source like a flashlight.

He started by pulling out most of the original electronics. Two dollar store toy trains gave their lives and their motors to replace the penguin’s original drive system. An Arduino Pro Mini became PenguinBot’s brain. Sensors consisted of two light sensing CdS cells, an AdaFruit sound sensor, and a MaxBotix ultrasonic sensor. With the ultrasonic sensor mounted on a servo, it can detect obstacles in any direction. The CdS cells and some software will allow PenguinBot to follow lights, like any good photovore robot should.

Click past the break to see PenguinBot in action

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Never Lose Your Pencil With OSkAR on Patrol


[Courtney] has been hard at work on OSkAR, an OpenCV based speaking robot. OSkAR is [Courney's] capstone project (pdf link) at Shepherd University in West Virginia, USA. The goal is for OSkAR to be an assistive robot. OSkAR will navigate a typical home environment, reporting objects it finds through speech synthesis software.

To accomplish this, [Courtney]  started with a Beagle Bone Black and a Logitech C920 webcam. The robot’s body was built using LEGO Mindstorms NXT parts. This means that when not operating autonomously, OSkAR can be controlled via Bluetooth from an Android phone. On the software side, [Courtney] began with the stock Angstrom Linux distribution for the BBB. After running into video problems, she switched her desktop environment to Xfce.  OpenCV provides the machine vision system. [Courtney] created models for several objects for OSkAR to recognize.

Right now, OSkAR’s life consists of wandering around the room looking for pencils and door frames. When a pencil or door is found, OSkAR announces the object, and whether it is to his left or his right. It may sound like a rather boring life for a robot, but the semester isn’t over yet. [Courtney] is still hard at work creating more object models, which will expand OSkAR’s interests into new areas.

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Building a Quadcopter with a CNC Mill and a 3D Printer


Quadcopters are a ton of fun to play with, and even more fun to build. [Vegard] wrote in to tell us about his amazing custom DIY quadcopter frame that uses a commercial flight control system.

Building a quadcopter is the perfect project to embark upon if you want to test out your new CNC mill and 3D printer. The mechanical systems are fairly simple, yet result in something unbelievably rewarding. With a total build time of 30 hours (including Sketchup modeling), the project is very manageable for weekend hackers. [Vegard's] post includes his build log as well as some hard learned lessons. There are also tons of pictures of the build. Be sure to read to read the end of the post, [Vegard] discusses why to “never trust a quadcopter” and other very useful information. See it in action after the break.

While the project was a great success, it sadly only had about 25 hours of flight-time before a fatal bird-strike resulted in quite a bit of damage. Have any of your quadcopters had a tragic run-in with another flying object? Let us know in the comments.

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Fixing Misaligned PVC With Kerf Bends


Our old pal [Jeremy Cook] is doing his own remix of [Theo Jansen]‘s Strandbeest, and like the original, he’s using PVC pipe. Unlike the originals, he’s powering it with motors, not wind, and this has caused a few problems in transmitting mechanical power through a piece of PVC. Nothing is perfect, and in a few points in the legs movement the shaft shakes violently. One motor was lost and another nearly so before [Jeremy] came up with a flex coupler made from PVC.

The technique [Jeremy] is using has seen a lot of use with people building laser cut enclosures. It’s called kerf bending, and it works simply by cutting a few slits in a panel that allow it to bend slightly. This technique was replicated by [Jeremy] on a miter saw, cutting eight slots halfway through a one inch PVC pipe, with each successive cut offset 90 degrees.

The new design works well for transmitting power, and he’s not ruining motors any more. Check out the video below.

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Measuring Magnetic Fields with a Robotic Arm


Learning how magnets and magnetic fields work is one thing, but actually being able to measure and see a magnetic field is another thing entirely! [Stanley's] latest project uses a magnetometer attached to a robotic arm with 3 degrees of freedom to measure magnetic fields.

Using servos and aluminium mounting hardware purchased from eBay, [Stanley] build a simple robot arm. He then hooked an HMC5883L magnetometer to the robotic arm. [Stanley] used an Atmega32u4 and the LUFA USB library to interface with this sensor since it has a high data rate. For those of you unfamiliar with LUFA, it is a Lightweight USB Framework for AVRs (formerly known as MyUSB). The results were plotted in MATLAB (Octave is free MATLAB alternative), a very powerful mathematical based scripting language. The plots almost perfectly match the field patterns learned in introductory classes on magnetism. Be sure to watching the robot arm take the measurements in the video after the break, it is very cool!

[Stanley] has graciously provided both the AVR code and the MATLAB script for his project at the end of his write-up. It would be very cool to see what other sensors could be used in this fashion! What other natural phenomena would be interesting to map in three dimensions?

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A Mini Op-Amp Based Line Following Robot


There’s no denying it. Super small robots are just cool. [Pinomelean] has posted an Instructable on how to create a mini line following robot using only analog circuitry. This would make a great demo project to show your friends and family what you’ve been up to.

Analog circuitry can be used instead of a microcontroller for many different applications, and this is one of them. The circuit consists of two op-amps that amplify the output of two phototransistors, which control each motor. This circuit is super simple yet very effective. The mechanical system is also quite cool and well thought out. To keep things simple, the motors drive the wheel treads, rather than directly through an axle. After the build was completed, the device needed to be calibrated by turning potentiometers that control the gain of each op-amp. Once everything is balanced, the robot runs great! See it in action after the break.

While not the smallest line follower we have seen, this robot is quite easy to reproduce. What little robots have you build lately? Send us a tip and let us know!

[via Embedded Lab]

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Telepresence Robot Proves It’s A Small World After All

jolvoy[Chris] works as part of a small team of developers in Cambridge, Massachusetts in the US. [Timo], one of their core members, works remotely from Heidelberg, Germany. In order to make [Timo] feel closer to the rest of the group, they built him a telepresence robot.

It was a link to DoubleRobotics that got the creative juices flowing. [Chris] and his team wanted to bring [Timo] into the room, but they didn’t have a spare $2499 USD in their budget. Instead they mated a standard motorized pan/tilt camera base with an RFduino Bluetooth kit. An application running on [Timo's] phone sends gyroscope status through the internet to the iPad on the robot. The robot’s iPad then sends that data via Bluetooth to the RFduino. The RFduino commands pan and tilt movements corresponding with those sensed by the gyroscope.  A video chat application runs on top of all this, allowing [Timo] to look around the room and converse with his coworkers.

All the source code is available via GitHub. The design didn’t work perfectly at first. [Chris] mentions the RFduino’s Bluetooth API is rather flaky when it comes to pairing operations. In the end the team was able to complete the robot and present it to [Timo] as a Valentine’s Day gift. For [Chris'] sake we hope [Timo] doesn’t spend too much of his time doing what his homepage URL would suggest: “”

[Thanks Parker]