Reverse engineering the Icebreaker POV toy

[Ch00f] spent some serious time figuring out how the Icebreaker POV toy works. This is a pretty cool device about the size of a toothbrush holder. It’s in a clear plastic case, which lets the row of 32 surface mount LEDs shine through. But making light isn’t their only function. You can use the device to scan in a high-contrast design, then ‘play it back’ using the persistence of vision display properties of the LED strip.

Perhaps the biggest question on [Ch00f's] mind was how the sensing is done. He made a series of observations, then started monkeying around with the LEDs to investigate them. It seems that one LED is lit up while the ones around it are used as light sensors. This becomes more confusing once he realized that the display was multiplexed.

His write-up includes a collection of schematics that can be pieced together to conceptualize the entire circuit. The image above was taken during this process, using an LED to check the connections on a part. This let him prove that it’s an N-channel MOSFET. He plans to take what learned and roll it into his own project.

[via Reddit]

POV bauble uses DIY accelerometer to sync the image

So we saw this tip come in and thought–oh, another POV device. We watched the video (embedded after the break), took a sip of coffee, then almost sprayed the beverage all over the computer when we realized that this uses a diy sensor to synchronize the POV image.

[Ch00f] came up with the idea for the sensor after seeing a similar implementation on a commercial POV toy. Instead of using a proper accelerometer to sense the motion, the toy uses a plastic bead in a channel. When you move the body of the toy the bead rolls to one end or the other, covering or exposing a reflective sensor.

A similar sensor is used here. A drinking straw servers as the channel, with a paper-covered nylon screw as the bead. [Ch00f] cut a window in the bottom of the straw for his reflective sensor, then sealed each end with a wad of paper.

This method works, but not as well as he had hoped. It seems the refresh rate and timing of the particular sensor he’s using is rather poor. If it were replaced with one that is simply and IR LED and phototransistor (like the sensors from [Jack's] last video) he thinks it would work a lot better.

via Buildlounge.

[Read more...]

Amazing RGB POV clock

rgb_pov_propeller_clock

We’re no strangers to POV time pieces around here, but something about them never gets old. Whether they use a ring of LEDs to draw clock hands, or an intricately cut HDD platter to replicate LCD segments, we love seeing them. [David] sent in this hard drive POV clock built by a fellow named [Kly], and it’s just beautiful.

[Kly’s] “Propeller” POV clock is named as such due to the design of the circuit board. The board is mounted on the HDD spindle, rotating much like an airplane’s propeller. The construction details are sparse, but from what we can find, it is based around a PIC32MX microcontroller, which is used to control the 66 SMD RGB LEDs mounted on the circuit board.

As you can see in the video below, the tightly packed LEDs result in some pretty amazing visuals.

Aside from watching the video below, be sure to swing by his Youtube channel for a handful of videos showing RGB POV clock in action.

[Read more...]

POV keychain from prototype to SMD board

[Augusto] wrote in to tell us about his keychain-sized persistence of vision project. He built the original prototype on some protoboard, using a PIC 16F627 to drive eight LEDs. Synchronization is managed by a tilt sensor on the board that starts the strobing to match the direction the board is traveling. This is a similar setup as the POV device that used an accelerometer, but it should be quite a bit easier to code for the tilt switch.

Once [Augusto] had the hardware dialed in he set to work laying out a surface mount design. The two AAA batteries were traded for a single 3V coin cell, which is on the back side of the board you see above. This is his first attempt at working with surface mount components and we think he did a great job. Check out the POV in action in the video after the break.

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More POV fan message hacking

[Zach's] company is all about the safety and to reinforce those ideals they handed out POV display fans to each employee. “Being Safe is Cool”, get it? Gimmicky… yes, but now [Zach's] got a tiny little POV fan to hack. Although he may not have known it, this isn’t the first time we’ve seen this hardware. These fans were handed out as a promotion at Black Hat a couple of years ago and prompted some reverse engineering action. The message is stored on an EEPROM and there’s even a female programming header that makes it easy to write reflash it with your own messages if you know how to craft the data.

This is where the two products diverge. The older project uses a serial connection and PonyProg to dump and data. [Zach] first tried using his Bus Pirate to dump the data but after having no success he grabbed his Arduino and managed to get the job done. Once the message encoding protocol was worked out, he wrote a sketch to flash the EEPROM. So if you can get your hands on one of these the work has already been done. See [Zach's] custom messages in the video after the break.

But we’d like to see this taken to the next level. How about a wall-mounted device that waits for something, like an incoming email or tweet, then spins up the fan to display it?

[Read more...]

Persistence of vision helicopter blades with RGB LEDs

A user named [BOcnc] on the rcgroups forums just posted his RGB POV helicopter blades.

The two blades are attached to the heli just as any other whirlygig. The electronics, though, are mounted underneath the blade with a battery pack. We covered a build last year that demonstrated weight added to a spinning blade won’t tear everything apart, but that build used only blue LEDs. This build is full color and makes us feel like we’re living in a cyberpunk future populated by Recognizers and Daft Punk.

The images are stored on an SD card that receives data from a USB port. The microcontroller is a PIC32, and from what we can assume from the schematics, the RPM of the blades is measured by an on-board hall effect sensor (don’t quote us on that, though). There’s no hope of a commercial release from [BOcnc], though. He can’t find anyone to manufacture the blades, and the entire build was too expensive. It sure looks pretty though, so check out the video of it after the break.

[Read more...]

Race car POV LED displays

race_car_pov

Last year, when [Alex] was asked by his friend [Martin] to help him out with building some LED POV modules for a race car, his response was a enthusiastic “YES!”

[Martin’s] goal was to involve fans more deeply in the race, so he decided that the POV modules would carry messages from fans on-board, printing them in the night as the race cars screamed around the track. The pair started prototyping and testing a design, wrapping things up shortly before this year’s 24 hours of Nürburgring.

The modules consist of an Arduino-compatible AVR, a GPS module, a 16-LED light bar, and the circuitry for driving the LEDs. While most of the components are pretty standard fare, the we don’t often see a GPS sensor built into a POV display. [Alex] says that the sensor is used to calculate the speed of the cars, ensuring a uniform font size.

They took their LED displays to the 24 hours of Nürburgring, where they were invited by Audi to install the modules on a pair of R8 Le Mans race cars. As you can see by the pictures on his blog and Flickr set, the POV units worked out nicely without having to stretch the camera exposure times too far.

If you’ re interested to hear a bit more about how the displays were built, check out this entry in[Alex’s] blog, where he goes through some additional details.

Update:[Alex] pointed us to the videos!

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