This electronic project uses temperature sensor LM35 and LM3914 IC to display the results on led bar displays. The sensor outputs 10mV/°C so we must convert this voltage to a visual signal. The LM3914 (Dot/Bar Display Driver) is a IC that senses analog voltage levels and drives 10 LEDs, providing a linear analog display depended on input voltage. This IC can be “chained” to form a display of 30 leds as done in this circuit. With proper adjustment of each IC’s range we can make first display to show 10°C to 19°C, second display to show 20°C to 29°C and so on. Check schematic here.
Electronic Thermometer using LM35 and LM3914 – [Link]