We developed a low cost telemetric system through a combination of a wireless microphone for signal transmission and a computer sound card for recording of signals. Three common communication systems, which are normally used for voice transmission, were compared for data transmission. The final developed telemeter provides a high potential for remote monitoring up to a distance of 30 m with a sampling rate of 10 Hz and 100% accuracy with low noise. The working signal range was from 0 to 2 volts, with resolution of more than a 10 bit A/D. A satisfactorily good precision of 0.1%RSD was achieved. The system works well for wireless monitoring of output from a spectrophotometer and pH meter. This work also demonstrated successful applications of the telemetric system with various chemical analyses.
Figure 1. An application of the telemetry for pH measurements. (a) Testing for wireless signal transmission from a pH meter. (b) Efficiency testing of two mixing devices (aquarium pump and air-bubbling bars). AQP: aquarium pump, E: combined-glass electrode, VCO: voltage-controlled oscillator.
(1) Amornthammarong, N.; Nacapricha, D.; Sereenonchai, K.; Anujarawat, P.; Wilairat, P. Telemetry: Research, Technology and Applications, Nova Science Publishers Inc., New York, 2009, 205-214.
(2) Nacapricha, D.; Amornthammarong, N.; Sereenonchai, K.; Anujarawat, P.; Wilairat, P. Talanta. 2007, 71, 605-609.