It's always the way. Just when you have to make that important phone call, your smartphone tells you it's time to recharge your battery and then promptly dies. Little wonder then that the backup charger market has become such a crowded space. Arguably the most appealing battery blocks available are those that can also offer off-grid emergency power from sources like PV panels or kinetic energy. The Voltmaker takes the latter approach, providing your smartphone with enough juice to make a quick phone call with a flick (or more accurately, several flicks) of the wrist.

CEO and founder of Paris-based Voltmakers Christophe Touchard told Gizmag that the four-strong design team explored a number of approaches to portable mechanical power generation before settling on the ratchet-inspired Voltmaker. After 18 months of development, tweaking and testing the team now has a working prototype they're happy with.

Housed within the Voltmaker's 6.1-in (15.5 cm) long, 1.6-in (4 cm) diameter painted aluminum tube sits a 2000 mAh Li-ion battery. It reportedly takes under 2 hours to charge the battery to capacity using a USB port on a computer, or via a USB adapter plugged into a wall outlet. Once it's full, a smartphone, music player or Satnav can draw juice from the device courtesy of the 5-volt Type A USB port at the bottom of the device. An LED status indicator will keep you posted on charge level.

But the main attraction is of course the ability to charge off-the-grid. When released from the grip of a hidden magnet, a rod secured to a spring-loaded mechanism at the top of the Voltmaker is pulled away from the device's body. Getting your rattle groove on causes the rod to spin around, and kinetic energy is harvested. After a few minutes of waving the device around like a person possessed, you should have enough juice to make a quick phone call on an otherwise dead phone, listen to a song or two, or light the way with the help of the LED torch attachment that slots into the USB port at the opposite end.

Though it is possible to fully charge the Voltmaker's battery using single-handed wrist action only, it will take you around 2 to 3 hours, so the developers recommend recharging its battery pack via the USB port for everyday use, and fall back on the shaker-method only when disaster strikes.

A built-in microcontroller takes care of the power management of different connected devices. It allows a computer/laptop to detect the Voltmaker and supply it with 500 mA of current instead of 100 mA for faster charging, and can increase the resistance of the spin as you fling your wrists around to generate more energy. Protection against deep discharge and overcharging is also in its brief, therefore increasing the operational life of the battery. It also has the potential to interact with smartphone apps to check remaining charge levels or indicate how much energy you're frantic wrist flicking is generating, for example, or perhaps even allow the Voltmaker to be used as a game controller.

The Voltmaker team has hit crowd-funding platform Indiegogo to raise enough money to take the device from working prototype to consumer product. A rather lofty target of US$200,000 has been set, but backers are promised a full refund in the event of an unsuccessful campaign. If successful, the first units will start shipping in October.

A few subtle changes are planned for the production units, including anodized aluminum (instead of painted) tubing and a slightly slimmer profile at 1.4 in (3.6 cm) in diameter. The team is also placing the Voltmaker on a diet and reducing its weight from 10.6 oz (300 g) to 8.8 oz (250 g), and swapping out the Li-ion battery pack for a more stable Li-Pol equivalent.

Given that it's bound to wind up in the great outdoors, the enclosure is sealed against dust and moisture penetration, though no IP rating has been given. There's also talk of releasing all of the custom code under a GNU GPL license to cater for third party app development, and the design team is currently working on expanding the range of plug-in attachments to include a radio, a fan, and an emergency strobe light.

Early bird specials are still available for $69, in a choice of green, blue, pink or aluminum. If you want a Voltmaker with flashlight attachment, however, you'll need to pledge at least $89.

The Voltmaker pitch video is below.

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