What is it?

Note: You are buying a limited beta run. This does not mean you get an unfinished product. The hardware you receive is final hardware, however due to limited resources I do not have the opportunity to test my firmware and software on every possible computer configuration. As an introductory offer, I give you a $20 discount on the regular product price and in exchange you promise that if you find bugs or have feature requests, you contact me. Also I will ask you to fill out a questionnaire after about a month of use. All firmware and software upgrades will be provided free of charge, so after the beta period you will have a finalized product.

You might have come across USB power sensors on eBay - little USB-stick sized devices with a screen on it that tells you how many mA (and mAh) is flowing to some downstream device. What I'm selling is essentially one of those sensors on steroids. My USB-sensor has:

• 1.8-5.5V, 0-2.5A (high range)/0-82mA (low range) sensing at up to 2.5µA/LSB resolution
• 0.75% +/-4mA basic accuracy, 0.05% +/- 28µA after calibration (1-day at 23C)
• True 18kHz analog bandwidth, allowing you to view details like the power consumption of a single USB packet transfer and power-up spikes
• 125kS/s sampling rate, meaning you will not get aliasing artefacts at any point
• Browser-based interface that can work anywhere - you can plug in this USB sensor halfway around the world and still read it out over the internet at full speed
• You don't have to use it just to view USB product power consumption; any 1.8-5.5V powered device can be read out by attaching the auxiliary power input port to your lab power supply (or battery). This allows for power consumption analysis of battery-powered devices like phones and tablets.
• You can log your data to CSV. Essentially unlimited logging is supported using sample decimation.
• The protocol documentation (provided with the sensor) allows you to develop your own software for this sensor, and any of my sensors in the future.

Essentially; this is a full replacement of a 2-multimeter setup PLUS convenient interface software for anyone developing USB hardware or developing apps and wanting to track down those nasty battery-draining code bugs.

Why did you make it?

This USB-sensor is the first sensor in a line of products under the series name MADPSU. I'm an engineer who mostly works in energy efficiency and IT equipment optimization. After fiddling around with LabVIEW and NI sensor boxes - which cost a fortune yet still require you to program essentially all analysis software - I figured I'd try designing my own sensor products. I initially designed this just for my own use, as I did most of my sensors. The USB-sensor was the first thing to make it to market simply because it's one of my simplest hardware products.

Also, this ties in with a very old project on my blog, which I called MADPSU or Measurable and Adjustable DC Power Supply - a PicoPSU-like product with in-built adjustable voltage regulators and accurate power sensing. Read more about the development of this project on my blog: http://ssj3gohan.tweakblogs.net/blog/6211/madpsu-a-measurable-and-adjustable-dc-psu-part-1.html. I even won an R&D prize for this!

What makes it special?

The combination of high-precision, very fast-sampling hardware and incredibly versatile software makes this a one-of-a-kind USB power sensor. I don't know of any other project with similar specifications (which is of course why I built it).