Spy Video TRAKR: Software And First Hack

September 2, 2010 by Phil Burgess 23 Comments

Our initial view of the Spy Video TRAKR “App BUILDR” site had us believing this would be an internet-based code editor and compiler, similar to the mbed microcontroller development tools. Delving deeper into the available resources, we’re not entirely sure that’s an accurate assessment — TRAKR may well permit or even require offline development after all. Regardless of the final plan, in the interim we have sniffed out the early documentation, libraries and standalone C compiler and have beaten it into submission for your entertainment, in order to produce our first TRAKR hack!

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Build Your Own Magnetic Levitator

August 31, 2010 by Mike Szczys 34 Comments

Here’s a great magnetic levitator build. [Scott Harden] dug up the link after seeing that awesome rotating globe this morning. This version hangs objects below an electromagnet but it has a sensor system to provide a constant distance between magnet and object even if the payloads are a different weight. This is done with a couple of infrared sensors. One acts as a reference detector, always viewing an IR LED in order to get a baseline measurement. That measurement is compared to a second detector mounted slightly lower. The circuit adjusts the electromagnetic field, making sure the object is always breaking the lower beam but never interrupting the reference beam. No microcontroller needed, this is handled with a couple of OpAmps. See it in action after the break.

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Floating Globe, Hacked To Rotate

August 31, 2010 by Caleb Kraft 56 Comments

they need to hire this guy

[Alexy Sha] has done this fantastic hack, where he modified a magnetic floating globe to be motorized and spin on a tilted axis. The original globe was simply levitating via a magnet mounted inside. Though you could spin it by hand, it wasn’t motorized, and actually floated completely vertically instead of being tilted.

[Alexy] wanted to take this idea further and make it automatically spin on a rotated axes. He built a rotation assembly that was basically a motor, hung off-center, attached at the center of the globe. He had to power it via a coil hidden in the base unit, so that it could remain light enough to float. He did a fantastic job and the final product seems like it is the true way it should have been sold.

Check out a video of it in action after the break. We actually like the spinning ring, when he’s testing it, just as much as the final spinning globe.

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Pressure Mapping Sensor Mat

August 30, 2010 by Mike Szczys 18 Comments

[imsolidstate] built his own pressure sensitive mat. It utilizes two discs of copper clad board with a piece of foam in between for each of 64 sensors. As the foam gets compressed, the capacitance between the two pieces of copper changes, a measurement that is fairly easy to make with an analog to digital converter. The mat is being used to measure how well a horse saddle fits the animal. Data is read in through a serial port and then mapped using Excel. This prototype proves that the concept works but [imsolidstate] mentions that there’s room to improve the sensitivity and that there could be more noise filtering incorporated into the design.

USB Typewriter

August 30, 2010 by Caleb Kraft 25 Comments

clickety-clackity-clickety-clackety-DING

[Jackzylkin] has posted an instructible showing, in detail, the process of creating a USB typewriter. He takes us through the process of disassembling the typewriter, mounting all the sensors where the little hammers strike, and wiring it all up to a custom board to interface with the computer via USB. While he is selling the board, the schematics are available if you want to build your own. We think the clickety-clack of a real typewriter could be very satisfying to the touch, though it might drive your co workers insane. The younger ones might also quiz you as to what that archaic machine is. We’ve actually seen this done before, way back in 2005.

Make Switched-mode Power Supplies Do Your Bidding

August 29, 2010 by Mike Szczys 31 Comments

[Ken] needed to supply 3.3 volts of regulated power. He started by using a linear voltage regulator but after a few calculations he discovered that 72% of what he put in was lost to heat. The solution to this is a switched-mode power supply. Rather than burn off energy through a voltage divider, an SMPS turns the power on and off very quickly to achieve the desired voltage.

A car charger-type USB regulator was chosen as [Ken’s] donor device. He figured that making adjustments to the resistors inside would affect the output voltage and he was right. He adjusted the potential divider and ended up with a steady 3.295V.

We asked him to share the schematic that he put together from studying the board and he came through. See that and get the link to the DC-DC converter datasheet after the break. Continue reading “Make Switched-mode Power Supplies Do Your Bidding” →

Prototyping The Bulbdial Clock

August 28, 2010 by Mike Szczys 1 Comment

Evil Mad Scientist posted a story about what went into developing the Bulbdial clock. We think the Bulbdial is one of the best pieces of kit out there for many reasons; using colored shadows for each hand is a brilliant idea, the design is clever and uses a low parts count, and the concentric rings that make it work also add to the aesthetic. But after seeing the original wood prototype it had crossed our minds that developing those circular PCBs isn’t the easiest thing to pull off. To save on board cost, the first run didn’t have the center routed out, but rather used almost-touching holes drilled during manufacture and finished by hand during assembly. They also go on to discuss the use of Charlieplexing to reduce part count and the search for a suitable diffuser for the clock face.