How-to: Networked Graffiti Wall

October 2, 2008 by Ian 22 Comments

[youtube=http://www.youtube.com/watch?v=G8KprTVbHD4]

Wondering what we did with our web server on a business card project from last week? It’s powering a giant LED graffiti wall. Animations can be user-submitted using the online designer. You can watch a live feed of user animations as well. The online interface runs on the Google App Engine for maximum scalability and resilience.

In today’s How-to we cover all the ins and outs of building your own networked graffiti wall. Continue reading “How-to: Networked Graffiti Wall” →

Amazingly Cheap Dual Channel Scope

October 2, 2008 by Caleb Kraft 20 Comments

[Jacques] sent us this little project he has been working on. It is an amazingly cheap USB 2 chanel scope. The total cost of the project was around 5 Euros. It is based off of an Atmel Tiny45, has 2 analog inputs, and can supply 5 Volts to a breadboard. He has listed the bill of materials as well as downloads for the source code, plans, and display software.

Autonomous Hovering Drones Invade Germany

October 1, 2008 by Caleb Kraft 11 Comments

We welcome the swarm of autonomous hovering robot overlords being made by students at Humboldt University. The goal of this project is to build an autonomous hovering platform that is controlled via adapted insect behavior. Navigation comes from monitoring real time inputs, such as air pressure and optical sensors, not by predefined paths and GPS coordinates. Some examples of this adapted behavior are: navigation via polarized sun light like African ants, and optical flow similar to bees.

You can see the platforms in action on Spiegel Online, but unless you understand German, you won’t get much else out of it.

If any of this seems familiar, it’s because we covered CCCamp 2007, which was near Berlin and had some very similar quadcopters. While the large quadcopter platforms have been around for a while and are steadily coming down in price, there are some new alternatives out there that are quite tempting. Anyone want to build some autonomy into this little baby?

[thanks fh]

Cheap XY Table Using Hobby Servos

September 30, 2008 by Caleb Kraft 6 Comments

[CarlS] wanted to build a low cost x y table for display on teletoyland.com. He realized that to keep cost low, he could use hobby servos instead of stepper motors. Exact precision wasn’t a big issue here, so the hobby servos would be perfectly acceptable.

Though Linear hobby servos are available, he decided that the cost was prohibitive. He used normal hobby servos, but had to modify their internals to get the exact amount of travel necessary. Many people modify the hobby servos for continuous rotation, but this would cause a loss in the ability for exact positioning. Instead, he replaced the potentiometer that measures the position of the servo with a 10 turn potentiometer. This allowed him 10x the travel.

Continue reading “Cheap XY Table Using Hobby Servos” →

Parts: 0.1uF Decoupling Capacitors

September 29, 2008 by Ian 30 Comments

Most ICs need to be decoupled from their power supply, usually with a 0.1uF capacitor between each power pin and ground. Decoupling is usually used to remove noise and to smooth power fluctuations. Every project will need a few decoupling capacitors; our mini web server project has three ICs that require a total of 11. This can be an expensive part to buy in singles, so it’s crucial to stock up online. Read more about our favorite bulk through-hole and surface mount decoupling capacitors after the break. Continue reading “Parts: 0.1uF Decoupling Capacitors” →

The Pinnacle Of Modern Robotics: Bar2D2

September 29, 2008 by Caleb Kraft 8 Comments

[Jamie Price] directed us to this photostream of the build for Bar2D2. Though it isn’t the first bartender bot we’ve covered. It very well could be the best executed. Bar2D2 can travel around the party dispensing bottles of beer, shots, and even cans. The construction looks fantastic. You can follow along in the photostream from the very beginning. It is currently radio controlled and can party for about 8 hours per charge. The next planned upgrade is a system that allows you to choose a mixed drink from a database and Bar2D2 will mix it up.

As you can see from the pictures, Bar2D2 is the life of the party, attracting pretty girls and cheesy sci-fi tv pirate astronauts too.

Peltier-based Cooling/heating Backpack

September 27, 2008 by Nick Caiello 16 Comments

[Max Weisel] recently created a Peltier-based cooling/heating system that fits into a backpack. The system uses two Peltier units, each running at 91.2 watts, with computer heat sinks mounted on one side of the unit to dissipate the excessive amounts of heat generated. While he was originally trying to build a cooling backpack, the use of the Peltier units meant that the cool side would become warm when the direction of current was switched, meaning that the backpack could become a heating backpack with the flip of a switch. In order to power the two Peltier units, he uses two 12v motorcycle batteries, weighing in at around 5 pounds each. While this backpack might be a little heavy for your back, it looks promising for anyone who needs to keep things cool (or warm) on the go.