Toy Helicopter Charging Fix

February 20, 2011 by Mike Szczys 16 Comments

[Onefivefour] was surprised that his E-flite Blade MCX radio controlled helicopter came with a charger that used AA batteries to recharge the lithium batteries in the flying unit. Yeah, that’s a bit crazy. He set out to modify the base unit to work with AC power. There are four batteries inside this base unit, one of them powers the charge detector circuit and the others are used to juice-up the chopper’s rechargeable cells. He took a 5V regulated charger from a Motorola cellphone and modified it to interface with the contacts for the three AA cells. Like the Magic Trackpad hack, he did this without altering the holder by cutting a couple of pencils to length and attaching the positive and negative contacts from the AC charger to them. Check out the video after the break for a walk though, noting how he still has the option to go back to battery power if he so chooses.

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Breathing Motion Powered USB Charger

December 5, 2010 by Mike Szczys 32 Comments

When your batteries run low you can use your body to recharge them. This contraption generates power from chest expansion while breathing. [Jmengel] used some gears from old optical drives to boost the RPM generated by a belt around your torso that he calls a thorax expansion coupler. When you breath in, that belt pulls on a plate that spins the gears, ultimately rotating a small motor. The AC current generated by that motor is run through a rectifier and a boost converter, then fed to a charging circuit.

Does it work? Not really, as this only outputs around 50 mW. But we like the twinge of Dune nostalgia we get looking at it. Wouldn’t this be a perfect addition to a stillsuit?

Ridiculous Exerciser Becomes Useful As A Charger

November 22, 2010 by Mike Szczys 41 Comments

[Scott Nietfeld] built a charger from a Dyna-flex wrist exerciser. We hadn’t heard of a these gyroscopic devices before but once we saw the promo video (embedded after the break) we realized that this is the kind of thing that infomercials were made to sell. [Scott] knew the internals spun to fairly high RPM and figured that adding a few magnets on the inside and coils on the outside would turn this thing into a generator. Four rare-earth magnets fit the bill, with two external coils feeding a rectifier and linear regulator. Below you can see his demonstration video where he takes the orb apart, then spins it up, generating 250 mA at about 7.5 volts to drive the regulator and charge a cellphone. Not bad!

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The Quest For A Bicycle Power System

August 3, 2010 by Mike Szczys 22 Comments

[Garote] has been extremely busy. Busy building an electrical system into his bicycle, and even busier writing a monumental post about it. He covers an impressive range of topics, starting with the goal of adding a generator, battery, charging system, lights, and accessories to the bike. From there he clicks off one thing at a time, researching and ordering a wheel with a Dynamo hub for the generator, assembling and testing the cells of his battery, choosing the controller board for the charging system, and designing the accessory circuits like the iPhone charger above. If he adds too much more to the two-wheeled rig he’s going to have to plan a big road trip with it.

[Thanks Xuxo]

Reverse Engineering Apple’s Recharging Scheme

August 3, 2010 by Mike Szczys 52 Comments

[vimeo=http://vimeo.com/13835359]

[Ladyada] has been hard at work reverse engineering the charging method used by Apple products. This saga takes us through the years as new devices were released and subsequently broke Minty Boost’s charging capabilities. It seems the data lines were gradually adopted as a means for iPhones and iPods to identify the charger that had been connected. By adding voltage dividers to the D+ and D- lines you can instruct the handheld to pull 1 Amp (with data voltages of 2.8v and 2.0v) for wall chargers or 0.5 Amps (2.0v on both data lines) for portable chargers. In the video above [Ladyada] removes the surface mount resistors from a commercial charger in order to measure the voltage divider and discover the secret.

Update: Custom Cellphone Induction Charging

August 1, 2010 by Mike Szczys 12 Comments

This is a custom back plate with induction charging circuitry that [Derek Hughes] build for his HTC HD2 cellphone. When we checked in with him last week he showed us how to add an inductive charger without voiding the warranty but it wasn’t very pretty because the stock back plate blocked the inductive field and couldn’t be used. The solution he came up with will work with any device if you want to put some time into the build.

He took two different aftermarket cases; one fits his cellphone and the other is a BlackBerry case meant for housing a credit card. After cutting a hole in the back of the cellphone case he epoxied the credit card holder in place, smoothed the seam with Bondo, and repainted. Not only does the charger fit in the credit card case, but there’s still room for a credit card. [Derek] also measured the magnetic fields around the circuitry and found they will not damage the magnetic strip on that American Express Black you’ve been keeping on you. In the video after the break he mentions the last step in finishing this case will be to locate a 90-degree USB plug as the current connector is a bit of an eyesore.

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

A More Powerful Boost Charger

May 2, 2010 by Mike Szczys 28 Comments

[Meseta] built a powerful boost charger to top off his portable devices. He was inspired by the Minty Boost but wanted to overcome the rather limited capacity provided by the two-celled product. He ended up building his own DC to DC boost circuit rather than using an all-in-one IC. As you can see, the result uses four 18650 lithium-ion cells, normally found in laptop batteries, and can power two USB devices at the same time.