Sample PC Interface using Liberty Basic (Mar, '05)
This is an assembled unit which interfaces with a PC COM port and provides the capability of measuring the relative humidity and temperature using a
When any character is received by the unit, a temperature measurement and relative humidity is performed and the result is returned to the PC;
28.62 55.13Note that the temperature is in degrees C.
If a communications error occurs, the temperature and RH is returned as;
The PCB is professionally fabricated. However, it was adapted from another design and includes a minor amount of hand rework.
The module includes a female DB9 connector, RS232 level shift circuitry, an on-board 5 VDC supply, a Microchip PIC processor, the SHT-71 sensor mounted on an SOIC to 8-pin DIP adaptor which is mounted in a socket and a two conductor screw type terminal block. There are three hole on the PCB to permit the user to mount the module in a box or on a plate. Three standoffs and #4-40 screws are provided.
The processor may be reset by momentarily connecting the two leads on the terminal block. This should not normally be necessary.