VHF Systems for Turtles and Tortoise (TOR)

Opt. MDC MK8 Duty Cycles. Transmitters can be programmed to cycle through up to eight sequential time periods or "duty cycles" in order to extend transmitter life. Within each duty cycle, the transmitter can either be "on" or "off". Pulse rates can be uniquely defined for each "on" duty cycle. Each duty cycle can be defined from eight seconds to approximately 50 months in length. Duty Cycle timing begins at the moment the magnet is removed to initialize the transmitter. Upon completion of the last programmed Duty Cycle Period, the transmitter begins again at the first duty cycle.

Opt. MA Activity Sensor. Varies the pulse period depending on the relative activity level of the animal. A motion-sensitive switch detects animal movements and the microprocessor monitors changes in the state of the switch (open vs. closed). A user-defined evaluation time is established and the number of switch state changes is recorded by the microprocessor. The maximum number of state changes is limited to one per second by the software. The transmitter pulse period varies between two user-defined pulse periods. One pulse period corresponds to "no activity" and the other corresponds to a user-defined "maximum activity level". A graph supplied with the transmitter correlates activity level and pulse period.

Opt. MS4 Temperature Sensor. Monitors body temperature in proximity to the collar on the animal (pulse period varies with temperature). User may define the desired pulse period vs temperature characteristic of the transmitter (contact factory for details). Standard temperature resolution is approximately 0.4°C. Optional high-resolution circuitry provides approximately 0.1° C resolution.
The MS4 temperature sensor circuitry provides accurate temperature measurements, even when the transmitter cannot be recovered and recalibrated after period of data collection. This virtually eliminates calibration drifts due to aging and battery voltage changes over time.

Opt. MS5 Temperature-Triggered Mortality Sensor. This option determines a mortality event in an endothermic animal with a stable body temperature. Faster (mortality) pulse rate is triggered when body temperature drops below a user specified temperature. Note:
Pulse rate is returned to original rate if temperature rises back above the specified temperature. Consideration of the ambient temperature is a consideration in selection of the transition threshold. For example, temperature-controlled sensors would probably not be suitable in areas where high ambient temperatures would prevent rapid cooling of body after death. This option is often used in monitoring waterfowl mortality events where motion sensitive mortality sensors may not be applicable (e.g. where the body may continue to be rocked by waves on the surface of a lake). Available in all implant configurations. Please contact the laboratory to discuss implementation of this sensor before ordering.

Opt. MS6 Mortality-Motion Sensor. Provides "active or alive" or "inactive or dead" pulse period depending on activity state of the study animal. A motion-sensitive switch is incorporated in the unit to detect animal movements. The microprocessor continuously monitors the motion switch to determine when motion occurs. Once per second, the microprocessor increments an "activity counter" if motion was detected during the preceding one-second time period. This "activity counter" keeps a running total of the number of times motion was detected over a user-defined mortality evaluation time (8 sec to 6 days). The active pulse period is maintained as long as the number of switch closures in the mortality evaluation time is greater than the mortality threshold. If the number of switch closures falls below the established threshold, the unit produces the inactive period. A separate resurrection threshold allows the unit to return to the active pulse period if the number of activity counts during the mortality evaluation time exceeds the resurrection threshold. Note:
The microprocessor updates the active/inactive pulse period at intervals of 1/16th of the evaluation time. This means that after the "resurrection" threshold criterion is met, there will be a delay of up to 6.25% of the evaluation time before the transmitter reverts to the "active" pulse period. The same is true with the transition between "active" and "inactive" pulse periods. The actual time between cessation of motion and initiation of the "inactive/dead" pulse period can be up to 6.25% longer than the evaluation time.

Opt. MS9 Tip Switch Sensor. Transmits one of two different pulse rates depending on orientation of the transmitter. Usually designed to switch pulse rates as it passes through an angle of 0° (parallel to horizontal). Other switching angles may be selected with some configurations (factory set within 10°).** Typical uses include monitoring "head up" and "head down" positions.