This article first appeared here.
Mindsensors was kind of enough to send me one of their prototype sensors, the Power Meter, to play with. It’s a sensor that allows you to measure, among other things, the current and voltage of anything you care to connect to it (within limits, of course).
The first thing that came to mind was building something that would log the incoming data to an Excel sheet using the NXT HID, but then Andy M scooped me on that so I had to come up with something else (damn you, Andy!). Then it hit me! Why not make an oscilloscope? So without further ado I started programming. This is what I came up with.
The result is quite nice, I must say. Right now it takes a sample every couple of milliseconds and refreshes the screen every 20 milliseconds. There are five scales for each unit (amps and volts), to cover the full range of the sensor (up to 13V5 and up to 3A). You can switch between ranges using the arrow keys and between units using the enter key. This program, together with the driver will be available with the next release of the 3rd Party Driver Suite.
Things I’d like to implement at some point is data recording, zooming and manual scrolling of the screen. I had the manual scrolling implemented at one point but ditched it for the cardiogram-look instead.
Another cool project using the Power Meter sensor can be found here: [LINK].
Written by Xander Soldaat
January 7th, 2010 at 5:44 am