Jonny Galvo: A Small, Low Cost Wireless Galvanostat

Abstract

A wireless, high resolution galvanostat is fabricated using smart dust technology for under $100 dollars using free software and general use hardware. We demonstrate a design that uses either PWM or DAC to set a current with up to 100 picoamp resolution for any value between -15 and 15 mA. An ADC measures the potential of the battery during charge cycles using a short (~400 µs) interrupt. A small foot print Java program controls the galvanostat and logs the ADC data. The device preforms well when tested against calibrated values for a variety of capacitors and resistors.