Content area
Full Text
J Comp Physiol B (2009) 179:451458 DOI 10.1007/s00360-008-0329-x
ORIGINAL PAPER
ModiWcation and miniaturization of Thermochron iButtons for surgical implantation into small animals
Barry G. Lovegrove
Received: 30 October 2008 / Revised: 4 December 2008 / Accepted: 8 December 2008 / Published online: 25 December 2008 Springer-Verlag 2008
Abstract Thermochron iButtons are being used increasingly by animal physiologists to measure long-term patterns of body temperature in reptiles, birds and mammals. Typically, iButtons are surgically implanted into the intraperitoneal cavity where they measure and store body temperature together with the date and time from an onboard real-time clock. In 16-bit resolution, the DS1922L iButton can store a total of 4,096 data points over pre-determined sampling intervals. iButtons have proved invaluable in measuring patterns of torpor and hibernation in animals larger than 70 g. Weighing around 3.5 g after potting with wax, iButtons are too heavy and large to implant into animals smaller than 70 g because their weight exceeds 5% of the animals total body weight. This paper describes how the stainless steel canister housing the DS 1922L iButton battery and circuit board can be removed to reduce the weight of the components to 1.49 g after waxing (ready for implantation) without compromising the function or battery life of the iButton. The modiWed iButton can be implanted into animals as small as 2030 g. Calibration data revealed an oVset of ca. 1C on average, conWrming that iButtons must be calibrated prior to implantation.
Keywords Thermochron iButton Body temperature
Aethomys Rhabdomys
Introduction
Thermochron iButtons (Dallas Semiconductor) are small (ca. 3 g) data loggers that integrate a thermometer, real time clock and memory for storing temperature, time and date recordings. The circuit board and battery of the iButton are encased in a robust stainless steel capsule. The recordings are stored at a user-deWned rate. iButtons communicate with host computing devices through a serial 1-Wire protocol, which requires a single data lead and a ground return.
Although Thermochron iButtons were designed for monitoring the temperatures of perishable goods during transportation, they are being used in many Welds of science as a relatively inexpensive, reliable and versatile means of measuring long-term temperature proWles. They are being used increasingly by animal physiologists to measure the internal body temperatures (Tb) of reptiles, birds...