LEGO Mindstorms Sudoku Solver

August 24, 2009 by 15 Comments

[youtube=http://www.youtube.com/watch?v=Mp8Y2yjV4fU]

Swedish hacker [Hans Andersson] is no stranger to puzzle-solving robots. His prior work, A Rubik’s cube-solving robot called Tilted Twister, made waves through the internet last year. [Hans’] latest project only has to work in two dimensions, but is no less clever. This new robot, built around the LEGO Mindstorms NXT system, “reads” a printed sudoku page, solves the puzzle, then fills out the solution right on the same page, confidently and in ink. It’s a well-rounded project that brings together an unexpected image scanner, image processing algorithms, and precise motor control, all using standard NXT elements.

The building instructions have not yet been posted, but if the video above and the directions for his prior ’bot are any indication, then we’re in for a treat; he simply has a knack for explaining things concisely and with visual clarity. The source code and the detailed PDF diagrams for Tilted Twister are as gorgeous as his new robot’s penmanship.

[thanks Eric]

Humanoid Robot + Homebrew Waldo = Big Smiles

August 24, 2009 by 11 Comments

[youtube=http://www.youtube.com/watch?v=WCTvggKuPvU&feature=player_embedded]

Robot enthusiast [Vitalijus Rodnovas] built this rig to allow a humanoid robot to mimic his own body movements in real time. [Rodonovas] refers to his man-machine interface as a “master-slave suit,” but elsewhere this is often called a waldo after a prescient 1942 [Robert Heinlein] novella. This project page is slight on details and is mostly written in his native Lithuanian, but the pictures speak volumes, and with a little help from Google Translate we can learn the essential facts: The robot itself is a commercially-available kit, the Kondo KHR-1HV from Japan. The custom-built harness uses a collection of surplus Soviet-era military potentiometers (acquired on eBay) to read the positions of his elbows and shoulders, then an ATmega8-based interface board translates these readings into motion commands sent to the robot’s onboard controller. Some additional notes and code can be found on the RoboSavvy Forum.

Does it work? Just watch. His grin as the video progresses is infectious!

Hack a Day has previously covered other Waldos, but this latest deserves style points for its lightweight simplicity.

Klipsch Speaker Mods

August 23, 2009 by 8 Comments

P1010021 (Custom)

[Patrick] has a pair of Klipsch speakers that continually needed the volume knob cleaned. After a bit of research, he found it was a common problem with the potentiometer chosen for the task. He decided to resolve the problem, not by replacing that potentiometer, but by modifying the speakers to be passive and running them from an external amp. While this does sound simple at first, he wanted to retain the rest of the electronics in the unit, so a bit of hacking was required. You can follow along through the whole process on his site.

Second Hard Drive In A Macbook Pro

August 23, 2009 by 23 Comments

Picture 4 (Custom)

[Reid] wrote in to show us how to add a second hard drive to his Macbook Pro. He found that he hardly ever used his DVD drive, so sacrificed it in favor of added storage. What he found was that it had a proprietary adapter that he was unable to find for sale anywhere. Making an adapter may seem like a pretty simple hack, but this could save some people considerable time. Its also worth noting that upgrading the firmware got him an 18% speed increase, so don’t ignore those updates. We don’t see too many mac hacks around here, you may recall the mac tablet hacks and the logo monitor.

Aspire One External Antenna

August 23, 2009 by 15 Comments

IMG_0023-300x225

External antennas on netbooks are notorious, from EEE PCs to the Panasonic CF-R1, but this is the first on an Acer Aspire One we’ve seen. [xRazorwirex] sent in his external antenna hack for the 802.11n capable D150, with the intention of increasing performance, but he says he can’t attest to any change. Unfortunately the lock slot had to be removed, but a small price to pay for a big increase in connectivity. The process seems simple enough, and could probably be done within a half an hour. Now that there is an external link why not build a Cantenna, hop in the car, and HeatMap the neighborhood!

Collect And Analyze ECG Data

August 22, 2009 by 14 Comments

ecg

Although we’ve covered DIY ECGs before, [Scott Harden] sent in his version that gives an in-depth explanation of what to do with the collected data. He built a basic battery-powered op-amp-based ECG for under $1. The circuit just amplifies the signal from the chest leads and feeds it into a computer via the microphone port. He then used GoldWave to record, filter, and save the signal. From there, he used python to analyze the heartbeat and calculate his heart rate and further manipulate the data. His previous blog posts go into more detail on how the python code works and why he chose software over hardware filters.

A Linux Server That Tweets Power Changes

August 22, 2009 by 21 Comments

apcupsd_twitter

Twitter has been used for lots of experiments, both useful and just for fun. [FIRESTORM_v1] sent in his project that falls under the useful category. When he wanted a way to monitor his server’s power statistics, Twitter was a logical choice. Similar to the Tweet-a-Watt, he wrote a script that posts messages from APCUPSd to a Twitter account that he follows, and gets the updates on his phone. [FIRESTORM_v1] documents all of the scripts he used and the steps to get your server up and tweeting.