POV Display Does It On The Cheap

July 23, 2014 by Adam Fabio 15 Comments

[Sholto] hacked together this ultra low-budget spinning display. He calls it a zoetrope, but we think it’s actually an LED based Persistence Of Vision (POV) affair. We’ve seen plenty of POV devices in the past, but this one proves that a hack doesn’t have to be expensive or pretty to work!

The major parts of the POV display were things that [Sholto] had lying around. A couple of candy tins, a simple brushed hobby motor, an Arduino Pro Mini, 7 green LEDs, and an old hall effect sensor were all that were required. Fancy displays might use commercial slip rings to transfer power, but [Sholto] made it work on the cheap!

The two tins provide a base for the display and the negative supply for the Arduino. The tins are soldered together and insulated from the motor, which is hot glued into the lower tin. A paper clip contacts the inside of the lid, making the entire assembly a slip ring for the negative side of the Arduino’s power supply. Some copper braid rubbing on the motor’s metal case forms the positive side.

[Sholto] chose his resistors to slightly overdrive his green LEDs. This makes the display appear brighter in POV use. During normal operation, the LEDs won’t be driven long enough to cause damage. If the software locks up with LEDs on though, all bets are off!

[Sholto] includes software for a pretty darn cool looking “saw wave” demo, and a simple numeric display. With a bit more work this could make a pretty cool POV clock, at least for as long as the motor brushes hold up!

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Talking BeagleBoard With [Jason Kridner]

July 22, 2014 by Mike Szczys 8 Comments

[Jason Kridner] is a member of the i3 Detroit hackerspace and during the Hackaday meet-up we were able to spend a few minutes talking about what’s going on with BeagleBoard right now. For those of you that don’t know, BeagleBoard is a non-profit foundation which guides the open hardware initiative of the same name. This includes BeagleBone which is the third iteration of the platform. [Jason’s] a good guy to talk to about this as he co-founded the organization and has been the driving force in the community ever since.

Right now the organization is participating in the Google Summer of Code. This initiative allows students to propose open source coding projects which will help move the community forward. Students with accepted proposals were paired with mentors and are paid for the quality code which is produced. One of the projects this year is a 100 Megahertz, 14-channel Logic Analyzer which [Jason] is waving around in the video. It’s the GSoC project of [Kumar Abhishek] and you can learn more from his proposal.

Also of interest in the video is a discussion about the power of the BeagleBone’s PRUs, or Programmable Real-Time Units. They’re basically unused microcontrollers that have direct access to a lot of the processor’s features and are just waiting for you to bend them to your will. Having these is a huge boon for hardware hackers. If you haven’t played with them before, check out our earlier article on what PRUs are all about and then give it a whirl yourself.

After the break there’s a brief table of contents which maps the topics shown off in the video.

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Smart Hat Puts Your Head In The Game

July 22, 2014 by Will Sweatman 8 Comments

man wearing a diy head mounted display

[Arvind] has dropped his hat in the game of head mounted displays. With Google Glass pushing $1,500, it’s only natural for hackers to make a cheaper alternative. [Avind’s] $80 version might not be pretty, but it gets the job done.

Using a Raspberry Pi loaded with speech recognition software, a webcam, 2.5 inch LCD display and a handful of other parts, [Arvind’s] hat mounted display allows him to view email, Google Maps, videos or just about anything he wants.

An aspheric loupe magnifier lens lets him see the display even though it sits around 5cm from his eye. No outside light is allowed in. Only the guts of the webcam were used to give him the video and microphone. We’ve seen other head mounted displays before, and this one adds to the growing collection. Be sure to check out [Arvinds] site for a tutorial on how to build your own, and catch a video of it in action after the break.

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HOPE X: Creating Smart Spaces With ReelyActive

July 22, 2014 by Brian Benchoff 10 Comments

When we hear about the Internet of Things, we’re thinking it’s a portable device with a sensor of some kind, a radio module, and the ability to push data up to the Internet. There’s nothing that says a device that puts data on the Internet has to be portable, though, as [Jeff] from ReelyActive showed us at HOPE X last weekend.

[Jeff]’s startup is working on a device that turns every space into a smart space. It does this with radio modules connected to a computer that listen to Bluetooth and the 868, 915 and 2400MHz bands. These modules turn every place into a smart space, identifying who just walked into a room, and who is at a specific location. Think of it as the invisible foundation for any truly smart house.

The radio modules themselves are daisychained with Cat5 cable, able to be plugged into a hub or existing Ethernet drops. The software that makes the whole thing work can run on just about anything; if you want a Raspi to turn on the lights when you enter a room, or turn off a thermostat when you leave a building, that’s just a few lines of code and a relay.

The software is open source, and [Jeff] and his team are looking at making the hardware open. It’s a great idea, and something that would be a good entry for The Hackaday Prize, but ReelyActive is located in Montréal, and like Syria and North Korea, we’re not allowed to run a contest in Quebec.

USB Rotary Phone: A Lync To The Past

July 22, 2014 by Kristina Panos 16 Comments

[Ivan] is fed up with all this rampant virtualization. When his company took away his physical desk phone in favor of using MS Lync, he was driven to build a USB rotary phone. His coworkers loved it and one of them asked [Ivan] to build another. The build log focuses on converting his coworker’s vintage brass and copper number that must weigh a ton.

He had to do a bit more work with this one because it had rusted out inside and a few of the contacts were bent. The good news is that the speaker and microphone were in working order and he was able to use them both. After restoring the stock functionality, he added a USB sound card and created a USB keyboard using a PIC32MX440F256H.

The rotary phone’s dial works using two switches, one that’s open and one that’s closed when no one is dialing. Once dialing is detected, the open switch closes and the closed switch clicks according to the dialed digit (ten clicks for 0). [Ivan] also reads the switch hook state and has added debouncing. This gave him some trouble because of the quick response expected by the PC bus, but he made use of interrupts and was allowed to keep his seat.

Please stay on the line. [Ivan]’s videos will be with you shortly.

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Judge Spotlight: Andrew “Bunnie” Huang

July 22, 2014 by Mike Szczys 6 Comments

judge-spotlight-bunnie

This week’s Judge Spotlight focuses on [Andrew “Bunnie” Huang]. If you haven’t heard of him you need to pay more attention. His hacker cred goes way back to the original Xbox, which he reverse engineered and laid bare its security flaws. Maintaining his hacker spirit he went on to design and hack the Chumby. More recently he took on the challenge of developing and Open laptop called Novena. All of this while continuing to explore and experiment with all kinds of electronics, posting about his adventures for those of us that care about an electronics ecosystem that doesn’t shut out the user from tinkering with the hardware. Join us after the break for our conversation with The Hackaday Prize judge [Bunnie Huang].

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Retrotechtacular: We’re Gonna Have Manual Transmissions The Way My Old Man Told Me!

July 22, 2014 by Kristina Panos 33 Comments

archimedes Simple machines are wonderful in their own right and serve as the cornerstones of many technological advances. This is certainly true for the humble lever and the role it plays in manual transmissions as evidenced in this week’s Retrotechtacular installment, the Chevrolet Motor Company’s 1936 film, “Spinning Levers”.

This educational gem happens to be a Jam Handy production. For you MST3K fans out there, he’s the guy behind shorts like Hired! from the episodes Bride of the Monster and the inimitable Manos: The Hands of Fate. Hilarity aside, “Spinning Levers” is a remarkably educational nine-ish minutes of slickly produced film that explains, well, how a manual transmission works. More specifically, it explains the 3-speed-plus-reverse transmissions of the early automobile era.

It begins with a nod to Archimedes’ assertion that a lever can move the world, explaining that the longer the lever, the better the magic. In a slightly different configuration, a lever can become a crank or even a double crank. Continuous motion of a lever or series of levers affords the most power for the least work, and this is illustrated with some top-drawer stop motion animation of two meshing paddle wheels.

gears Next, we are shown how engine power is transferred to the rear wheels: it travels from a gear on the engine shaft to a gear on the drive shaft through gears on the countershaft. At low speeds, we let the smallest gear on the countershaft turn the largest gear on the drive shaft. When the engine is turning 90 RPM, the rear wheel turns at 30 RPM. At high speeds using high gears, the power goes directly from the engine shaft to the drive shaft and the RPM on both is equal. The film goes on to explain how the gearbox handles reverse, and the vast improvements to transmission life made possible through synchromesh gearing.