A dynamometer readout (42, 46) and method is disclosed for obtaining dynamometer information (110) related to pumpjacks (10). For this purpose, a change of pivotal direction of the walking beam (18) may be detected by processor (82) utilizing an encoder component (60) with spaced slots (64) therein and light signal devices (68, 70, 72, 74) positioned to have a spacing different from that of the spacing of the slots (64). Software techniques filter out effects of stray mechanical vibrations. An infrared transceiver (46, 50, 100) of a preferred embodiment includes a radio frequency carrier generator (90) and modulator (88) that produces an infrared signal receivable by a low cost consumer radio receiver. The radio frequency modulation technique for infrared signals (96) and related filtering (98, 102, 104) condition formatted infrared signals for utilization in daylight and through a car window for drive-by downloading of data to second computer (108). A sensor (163) may be substituted for the encoder. A sensor (163) may include a moveable light interrupter, such as a ball (160) or a bubble (260), moveably disposed within the sensor. The sensor may also provide one or more apertures (180) for transmitting light through the apertures.