I wrote a press release for the project.
There is a consensus in the electronics community that a quality power supply is crucial for computer engineering but most variable power supplies plug in to a wall outlet and they are large and very inconvenient to carry while traveling.
Mike, a systems architect and designer of the VariPower 500A device explains how the device came about. "Many times while traveling, I have had the need to debug my firmware on a circuit board. Unfortunately, I was not carrying a power supply. So in turn, I had to wait until I reached my lab before I could power my circuit board to test the new firmware. This new innovative project, the USB Based Variable Power Supply, will solve this issue effectively, affordably, and reliably."
VariPower-USB-500A is open source hardware, all hardware design files and firmware source code are released under the GPL v2 license.
With 24 pledges on Kickstarter and over $800 potentially raised the first day, this device appears to have caught the eye of their target audience.
Brad Hunter, also an inventor, designed the devices sticker and t-shirt that is a pledge reward. Brad says this about the VariPower USB power supply, "When Mike first asked me my opinion about the concept, I was floored that there was not something in the market already. The premise is simple and the function is needed. There is a whole community of students, hackers and engineers that can benefit from this device. Devices like Arduino and similar project boards will benefit greatly from a stable and easy to use power supply."
The project is on Kickstarter.com and is officially called "USB Based Variable Power Supply for Small Projects." Currently, Kickstarter.com is the only way to get one of the devices. The basic device on Kickstarter requires a $30 pledge. To make a pledge and or get a unit, go to www.kickstarter.com and search "variable power supply".
I had a quick look at the schematic of this design and it isn't really very nice at all.
It takes power from a USB port but has no connections to the data lines so it's pot luck if any given host will supply more than 100mA.
It uses a buck mode switching regulator specced to work from 4.75V upwards - that's not really enough margin for a device powered from USB where, in practice, you often get less than 4.75V.
The (regulated) output voltage range will be 4.5V down to perhaps 1.25V.
It does have a 3 digit display which is based on a little Renesas micro.
Some of the parts are hard to source in the UK (only a problem if that's where you are !)
For 99% of applications a fixed 3.3V supply would do as well (and you could do without the meter).
VariPower-USB-500A is an USB based variable power supply. It is an open source hardware, all hardware design files and firmware source code are released under the GPL v2 license.
Here is the detail,