Feb 21, 2009

Hide and Go Seek GPS Style

Hide and Go Seek. Age old game of one person hides, the other counts to to ten with eyes closed, and then goes to find person A who went to hide. Now add a radio signal, converted to GPS signal, a VHF radio, and a couple of geeky fruit cakes driving around following a giant arrow and you have our Friday night.

We first hooked up our tiny MSI U90 to a camera stand turned laptop holder in the car.

Then we hooked up the sound from the VHF radio which was receiving the radio signal, into the microphone jack of the computer. We plugged in the cute GPS unit (cute because its tiny) and stuck the USB part into the computer and the GPS transmitter to the dash.

We turned on our TomTom, using only the map function so we could see upcoming changes in the road and set about on our way. Following the giant arrow of knowledge, we drove approximately 25km and found our target, after making only one wrong turn and getting ourselves stuck on the wrong side of some railroad tracks. We arrived, 6 meters from our goal, a big radio tower at a friend's work. However, we were informed that this wasn't close enough so we had to park even closer, and reach the 1 meter point. We found our goal, a blinking red GPS unit, at the base of the tower generating the radio signal.

We then were going to head to said friend's house for dinner, and thought that instead of dumbly following his car (in the snow) we should... play hide and go seek. He changed his VHF radio to output a signal, and we fixed on it, and away we went. We followed him, lost him visually and were able to track him down despite him trying to trick us by pulling off the road and hiding on side roads. The signal was clear and our arrow true.

A fun night of radio and gps geekery. :)

See Flickr for photos.

Feb 19, 2009

Fun with Robot Building

GeekPhysical and Illutron did a workshop this week in Odense, teaching students all about Arduino, electronics, physical computing, using sensors, and building robots from RC Motors! We had a ton of fun, and were happy to see people being creative with their robot building.

Our robots consisted of servo motors, one small and one big, glued to each other with the smaller on top. This one had a stick glued to it which could be used to pick up objects. Participants were taught using Pure Data and the pduino interface so they could easily associate the programming with what they were doing.

Our next goal is to build a patch that allows sensors AND the servo to be connected at the same time, so that we can use sensors to control the servo! In the meantime, check out http://illutron.dk/posts/214 to see what the next day, and a couple of guys crazy about computer vision used the robots for. Hint, control a robot with fruit! Woohoo!

Video on bliptv here: http://blip.tv/file/1792054/

Flickr Set here: http://www.flickr.com/photos/29889578@N05/sets/72157614072570567/

Feb 14, 2009

MSI Wind Power Supply, reimagined, rebuilt.

There is possibly nothing more annoying than having your power supply weigh more than your computer. This isn't EXACTLY the case with the MSI Wind U90 but it very nearly is. As such, it was ridiculous to carry around the power supply it came with, since the power supply took up more room in my bag than the computer did.

We found a 24V AC Adapter, which although the MSI suggests 20V it runs fine on 24V. (These are readily available at any electronics store). Then the connector was changed to one that would fit the MSI, a standard DC connector. An easy do-it-yourself project, we hope we can pass on the knowledge to other MSI owners.

While we were at it, we thought making the MSI available for long car trips would be great. We made a boost converter, boosting from 12V in the car to the 20V needed for the MSI. Rather than using a standard power supply integrated circuit (chip) we decided to use a microcontroller so that we can add intelligent battery protection. The microcontroller generates the pwm signals for the boost converter and measures input and output voltages. It checks the input signal and only turns on the output only if the car battery is over 13V - meaning either the engine is running or you have a really good battery. If the car battery goes below 11V (a problem in our slightly used car) it will shut off the power supply to the laptop.

Schematic and do-it-yourself instructions coming soon.

Robot from household materials

CDs? Check. Mouse? Check. Tires from toys? Yep. Okay you're ready to make a robot. It might require a couple more parts, (Arduino board, servo motor) but not much! Its a fully functional self-guiding robot that uses a computer mouse as its vision, and a CD as its body. A work of art, and a new friend/pet all in one.

Using an optical mouse for navigation, modified servos for propulsion, and a lens on mouse sensor to track movements in the surroundings, this robot studies the use of optical flow for robotic navigation.

Revolving pictures, a DMX/MAX/MSP/Motor job

Flying to Spain for two days was a good excuse for tapas and red wine. However, our goal was instead to get a large art installation up and running on a much simpler system than it currently did. This wasn't our first encounter with this project, it first needed a system to run motors which turned giant picture frames, as they turned they aligned to create a beautiful story complete with audio story teller. Once the motor system was in place, it was time for an integrated DMX controller to take care of the sound, lights and motors all in one shot.

Giving an ABB Robot Life (Again)

After happening across 4 giant 1 ton ABB robots, we decided to reverse-engineer them to figure out how they work, and how they can be reprogrammed. This involves the solving of generalized servo-loop problems and creating new hardware for them so they can move again.

The robots used to live a dreary life, grinding toilets, and were decommissioned. We rescued four of them and managed to pull of their arms and start looking at their insides. Horrible sounding, but a fun job that's going to be more fun once they start working!

Right now, we've got the motor turning via potentiometer. When the potentiometer turns, the motor turns.