Wireless RF Transmission of Temperature Reading

The project was created to measure temperatures of remote objects with the use of wireless RF transmitter using TXM-433 module and the receiver uses ATmega8 SILRX-433 with connection to PC through RS232 port.

During the operation, 6 bytes of data at fixed interval are being sent by through RF temperature transmitter. There are 3 temperature values, light level at photocell and battery voltage that are measured by the module. The data collected by the small Visual Basic program is displayed in a table view. The program code is written for GCC compiler and the device is universal making it suitable for other purposes.

The design originally uses AT90S4433 and is replaced with an ATmega8 with added timing charge capacitor circuit. The use of power down sleep mode instead of idle mode is allowed due to the slowly discharging capacitor instead of the internal clock for the long time delay, which makes use of no current effectively except when transmitting. The 78L05 regulator was replaced with a TL750L05 LDO regulator since 98% from the 5V regulator is being drawn by the board.

The software needs to be installed like any other Windows application.

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