2002 Denver Annual Meeting (October 27-30, 2002)

Paper No. 21
Presentation Time: 8:00 AM-12:00 PM


MCKINNEY, D. Brooks and HALFMAN, John D., Department of Geoscience, Hobart and William Smith Colleges, Geneva, NY 14456, dbmck@hws.edu

A new version of the Hobart and William Smith Datalogger with improved resolution and higher storage capacity is now available to the education and research communities. The HWS Datalogger is a user-built, battery-powered, digital data recorder that can be adapted for use with a variety of analog sensors. The collected data is downloaded to a PC-compatible computer for analysis and storage by a reader unit linked to the computer and datalogger by serial cables. The HWS Datalogger's most important characteristic is low cost. A datalogger can be built in a half an hour for less than $20 and requires only reasonable manual dexterity. This makes it economically feasible to deploy arrays of loggers to monitor spatially and temporally varying environmental parameters in a wide range of educational and research contexts. We use the dataloggers to investigate stream stage height, microclimates and seiche activity. Other investigators apply them to groundwater and soil moisture problems. The new version uses recently introduced integrated circuits with 12-bit rather than 8-bit analog to digital conversion (ADC) and increased storage. The 12-bit ADC boosts the theoretical resolution of the datalogger by 16 times to 1 part in 4096. This higher resolution provides better quality data, but also makes it less critical to fully match sensor output to the expected data range, easing the task of interfacing the datalogger with a variety of sensors. Data storage is increased as well, from a capacity of 4K to16K. These improvements add less than $1 to the cost. Investigators who have built the original 8-bit/4K version can upgrade by reprogramming or replacing the reader and datalogger integrated circuits, updating the PC host software and installing a jumper wire on the datalogger circuit board. A complete description of the datalogger and links to download software, construction and use manuals (including upgrade instructions), and parts lists is available on the datalogger web site, http://academic.hws.edu/geo/logger/logger.html.