Share Your Hackaday Story As We Celebrate 10 Great Years

October 3, 2014 by 8 Comments

Tomorrow we mark 10 wonderful years of reading Hackaday. Share your experience by recording a 1-2 minute video about how you discovered Hackaday and your favorite hack from all the greats that have hit the front page. Tweet the link to your video to @Hackaday with the hashtag #10years and we’ll add it to the playlist.

It doesn’t need to be anything special (but go nuts if you wish). I recorded a one-shot talking-head format as an example.

If you are lucky enough to be in the LA area, get a free ticket for Saturday’s event. In addition to all the clinicians and speakers, there’s a small collection of the Hackaday crew in town.

Trek To Evil Mad Scientist Laboratories

October 3, 2014 by 5 Comments

I’ve been a huge fan of EMSL for quite some time now, and my recent field trip proved that it has earned the name Evil Mad Scientist Laboratories for a good reason. For instance, look at the reflection in the glass near the bottom and you’ll glimpse the hearse that [Lenore] and [Windell] have sitting in front of the shop. But stop at the threshold, inside there are delights that ate up a couple of hours without me even noticing. And they thought they were going to get work done that day.

Don’t judge me by my appearance. This is late afternoon on a summer Saturday in Sunnyvale. Why does that matter? Obviously summer Saturdays in Silicon Valley always start with the Electronics Swap Meet and Engineer’s breakfast! That was a ton of fun but if you’re doing it right it’s also a bit tiring. No worries, a shot of excitement came over me as soon as I walked in that front door.

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Leap motion controller plus oculus rift

Interacting With Virtual Reality Brings Us Even Closer To A Real Holodeck

October 3, 2014 by 6 Comments

One of our readers has been playing around with virtual reality lately, and has come up with a pretty cool beta run of his research — virtual interaction using your hands.

Using an Oculus Rift, the Leap Motion controller and a beta run of Unity 4.6, [Tomáš Mariančík] put together a test environment for physical interaction. The Leap Motion controller is capable of tracking your fingers with extremely high detail, which allows him to create a pair of virtual hands inside the test environment that almost perfectly mimic his movements. The hack here is making it all work together.

In the following demo he shows off by interacting with holographic menus, grabbing body parts off of anatomically correct human being (thanks to Unity3D), and manipulating his environment.

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Joule Thief Steals Power For A Clock

October 3, 2014 by 14 Comments

A common project among electronics tinkerers is the joule thief, a self-oscillating circuit that can “steal” the remaining energy in a battery after the voltage has dropped so low that most devices would stop working. Typically the circuit powers an LED until almost all of the energy is extracted from the battery, but [Lionel Sears] has created a specialized joule theif that uses the “extra” energy to power a clock.

The circuit uses four coils instead of the usual two to extract energy from the battery. The circuit charges a large capacitor which provides the higher current pulses needed to drive the clock’s mechanism. It can power the clock from a single AA battery, and will run until the voltage on the battery is only 0.5 volts.

Normally the clock would stop running well before the voltage drops this low, despite the fact that there’s still a little chemical energy left in the batteries. The circuit can drive the clock for an extended time with a new battery, or could use old “dead” batteries to run the clock for a brief time while the final little bit of energy is drawn from them. If you’re so inclined, you could even use hot and cold water with a joule thief to run your clock! Thanks to [Steven] for the tip.

Transformer Inductive Coupling Simulation Is SFW

October 2, 2014 by 12 Comments

[James] has a friend who teaches at the local community college. When this friend asked him to build a transformer coupling simulation, he was more than happy to oblige. Fortunately for us, he also made a video that explains what is happening while  showing the output on a ‘scope.

For the simulation, [James] built primary and secondary coils using PVC pipe. The primary coil consists of 11 turns of 14AWG stranded wire with 4V running through it applied. The first secondary he demonstrates is similarly built, but has 13 turns. As you’ll see, the first coil induces ~1.5V in the second coil. [James] first couples it with the two windings going the same way, which results in the two 2Mhz waveforms being in phase with each other. When he inserts the secondary the other way, its waveform is out of phase with the primary’s.

His second secondary has the same diameter PVC core, but was wound with ~60 turns of much thinner wire—28AWG bell wire to be exact. This match-up induces 10V on the secondary coil from the 4V he put on the primary. [James]’ demonstration includes a brief Lissajous pattern near the end. If you don’t know enough about those, here’s a good demonstration of the basics coupled with an explanation of the mechanics behind them.

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Auto Bike Light: On When Moving Off When Not

October 2, 2014 by 72 Comments

If you’re plagued by perpetually dead bike light batteries you’ll like this one. It’ll also fix the problem of remembering to turn the lights on in the first place. This hack uses an accelerometer to switch the light when the bike is in motion.

In this case the bike light was chosen for its ability to fit the control board inside the case. But with this proof-of-concept you can easily spin a tiny board with uC and accelerometer to replicate the functionality (the Bluetooth module shown above is going unused in this application). Many accelerometer chips have low-power mode that can be used to was a uC so we could easily see this having very little impact on the normally battery life of your light. The one caveat being the need to regulate the voltage as many of these lights take a 12V cell.

The other alternative is to make sure your battery is always charging during the day. This solar setup is one way, but then you won’t want to leave the thing unattended.

 

Even More Power Wheels Racers

October 2, 2014 by 18 Comments

With the Power Wheels Racing series wrapping up for the year, the teams are winding down and writing up their build and rebuild logs for their cars. In previous years, the kids from MIT, a.k.a. MITERS, have brought small electric cars to the races, but nothing like this. It’s a true Power Wheels, or at least the plastic shell, an alternator, a huge battery pack, and a completely custom drivetrain.

[Dane], [Ben], [Rob], [Mike], and [Ciaran] started their build with an alternator that was salvaged from [Charles]’ Chibi-Mikuvan, added a motor from a CDROM drive for a sensor, and basked in the glory of what this cart would become. The frame was crafted from 1″ square tube, a custom disc brake machined, and a 10S2P battery pack built.

The alternator the team used for a motor had a rather small shaft, and there were no readily available gearboxes. The team opted to build their own with helical gears milled on the MITERS Bridgeport mill. That in itself is worth of a Hackaday post. Just check out this video.

With the build held together with duct tape a baling wire, the team headed out to the races in Detroit. Testing the racer before getting to Detroit would have been a good idea. During the endurance race, a set of 10″ rear tires were torn apart in just four laps, impressively bad, until you realize the smaller pink tires that were also from Harbor Freight fared even worse.

After a few races, the MITERS team figured out the weaknesses of their car and managed to get everything working perfectly for the race at Maker Faire NY.

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