Designing Barometers From Simple Circuitry

EE 45 January 1989 DESIGN IDEAS The contents of this column are based solely on information supplied by the author and do not imply practical experience by Elektor Electronics. DESIGNING BAROMETERS FROM SIMPLE CIRCUITRY by E.A. (Babs) Barber* and Scott Weatherwax Two different types of low-cost, solid state barometers can be designed with the Sensym SCX15ANC absolute pressure sensor. The first uses a 15-volt power supply and produces an analogue output voltage, that is proportional to the barometric pressure, which can be easily scaled to respresent mBar, mmHg or inHg. The second uses a 9-volt battery with a 31/2 digit LCD display signal output. This gives a portable, digital barometer which could be used by a hiker. Analogue voltage output example (scaled in mBar) To construct a barometer with an output voltage directly proportional to the barometric pressure, the circuit shown in Figure 1 is required. Amplifier At is used to supply a 10 V regulated voltage to the sensor. In this...