Temperature Measurement Range : 0 to 150'C
32 to 300’F
Controller: ATtiny 85
Display type - 4 digit multiplexed 7 segment display(Common Cathode type)
Programming Language: Arduino
The setup can display both in Celsius and Fahrenheit. By default the temperature is shown in Celsius but can be toggled to display in Fahrenheit using the push button.
Step 1: Working
The MAX7219 is a compact, serial input/output common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits. It implements a SPI compatible slave interface that can be controlled from the Arduino using only 3 of the digital output pins.
All the necessary calculations and control signals are generated by the ATtiny85. The Data, CLK & Load pin of MAX7219 is connected to pin 2,1,0 of the ATtiny85 respectively. Analog output from LM35 is feed to the ADC channel 3 of the ATtiny85.