Hi: We are wiring 15 hives to continuously monitor anything and everything that we can - brood nest temperature, relative humidity, bee flight activity, air flow direction and speed, etc. These are small nucleus hives, with 1-3 pounds of bees, and 10-30 pounds total weight (depending on time of year, experiments being conducted, etc.). All of the hives are mounted on a roof and all of the measurements are being conducted using a 486 IBM-compatible PC with an A-bus card data system. Our biggest technical problem is in finding an accurate, yet inexpensive, sensor to monitor hive weight changes. We have tried a variety of pressure transducers, pizeos, etc. They tend to either be too insensitive to pick up small changes such as bees coming and going, or too expensive (we can't afford to put a research grade electronic balance under each hive). We would like to keep the cost below $200 per hive. If anyone has any insights or can point us to components - or even better - circuit diagrams, please respond directly to us. Thanks Jerry J. Bromenshenk The University of Montana Missoula, MT 59812 Tel: 406-243-5648 Fax: 406-243-4184 E-Mail: [log in to unmask]