ATmega8 Used for Data Acquisition System

This homemade data acquisition hardware is made to connect with a PC for easily producing the GUI for user friendly graphical presentation.

An ATmega8 microcontroller is used to build the circuit since a 10-bit resolution A/D converter is contained in the chip. Connected to the 6 channels ADC input is the temperature sensor while up to 8 sensors can be connected with the ATmega8 TQFP package. The PC is used to send a command that captures the analog inputs. The data will be displayed graphically or as text by the readings and the data can be recorded as the database.

The ATmega8 comes with the serial interface and the LM335 temperature sensor on the board. The reading of ADC is controlled by the on-chip firmware as well as receiving commands from PC and sending the reading to the PC. An 8MHz crystal oscillator is included in the microcontroller although it may be eliminated by using the internal RC oscillator. The temperature can be measured remotely by the LM335 temperature sensor using two wires. An output signal proportional to the Celcius temperature scale is produced by the chip and involves output voltage calibration.

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