Simple Telemetering System for Signaling High Rumen Pressures

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Science  26 Feb 1960:
Vol. 131, Issue 3400, pp. 611-612
DOI: 10.1126/science.131.3400.611


The construction of a modified Hartley oscillator transmitter activated through a pressure switch is described. When this device is placed within the rumen of a cow which is allowed unrestricted movement in the pasture, frequency-modulation signals are transmitted to a recording receiver whenever a preselected pressure is exceeded. The pressure at which transmission begins is determined by the capacitance across the coil of the circuit.