Dataloggers @ SmartSpark Energy Systems

Four versions
	of dataloggers developed at SSES After graduating with my degree in Electrical Engineering, I sort of fell into working at SmartSpark, the company I was moonlighting for while a student. They were designing a family of charge balancing devices for long strings of batteries. My first task, among others, was to design, assemble and test a family of embeddable dataloggers. The purpose of these loggers was to gather all the data we could about batteries including temperature, current, and individual cell voltages. These values were sampled at programmable time intervals, and the data stored as a CSV table on a FAT-16 file system on an SD card. All used some variant of the MSP430, since it is low power, has relatively cheap development tools, and a very nice set of a/d peripherals are available on board.
The family grew to five versions for different projects we were working with, four of which are shown at right. The far left in the photo was the first prototype, the next one for an "intelligent" battery pack, and the next two were versions of a standalone version to be installed in the customers' equipment. The most tricky thing about doing this, which kept getting in the way, was doing cheap, relatively high accuracy current measurement.

Weatherproof datalogger The final version I worked on was for a really, really slick product that SSES has. This product is called ForeverPower, a battery-free box that provides small amounts of power for long-term unattended loads. The datalogger in this photo was used in some of our early testing for ForeverPower. Two of these units were mounted on the roof of our building. I learned a great deal about weatherproofing electronics and low-power design. I'm a big believer in MSP430's now. The dev kits are cheap, the facilities are wonderful, and there is a fair amount of available libraries out there to make certain tasks easier. I used enclosures that I had in my personal parts archive, and I modified the boxes, mounted the batteries, and wired up the connectors in my apartment. This was easier than crudding up the Lab at work with extra tools and plastic shavings. This particular unit has channels for time, temperature, current, and voltages.

A datalogger
	installed on a battery pack demo board This is a twelve channel board installed atop one of our charge balancing boards. This unit does 12 voltage channels, a current, a temperature, and time. The logger PCB, sitting up on standoffs, is only something like 1.5" x 3" . To my knowledge SmartSpark Energy Systems is still developing these units for internal development, specifically the one for ForeverPower, which was not exactly bug free when my career plans changed.