Intelligent thermostat temperature sensor LM75 circuit diagram consisting

The circuit features simple smart temperature sensors utilizing an I2C bus interface, designed as a thermostat controller circuit. It employs the LM75 temperature sensor connected to a 2N3904 transistor, which drives a relay coil. The relay operates based on the measured ambient temperature levels to control the power to the thermostat, facilitating climate control.

The described thermostat controller circuit operates using an LM75 temperature sensor, which communicates over the I2C bus. The LM75 is a digital temperature sensor that provides accurate temperature readings and can be configured to operate in various modes, including alert modes for temperature thresholds.

In this circuit, the LM75 outputs a digital signal that represents the ambient temperature. This output is connected to the base of the 2N3904 NPN transistor, which functions as a switch. When the temperature reading exceeds a pre-defined threshold, the LM75 sends a high signal to the transistor. The 2N3904, when activated, allows current to flow from its collector to its emitter, thereby energizing the relay coil.

The relay is essential for controlling the power to the thermostat. It acts as an electrically operated switch that can handle higher voltage and current levels than the LM75 and 2N3904 can manage directly. The relay contacts are connected to the power supply of the heating or cooling unit, allowing the thermostat to turn these devices on or off based on the ambient temperature readings.

This configuration allows for effective climate control by automatically adjusting the heating or cooling system in response to temperature changes, ensuring a comfortable environment. The use of the I2C bus interface simplifies the wiring and communication between the temperature sensor and the controlling circuit, making the design more efficient and scalable for various applications. As shown by simple smart temperature sensors based on I2C bus interface configured as shown thermostat controller circuit. LM75 through 2N3904 transistor to drive the relay coi l K, according to the measured level of ambient temperature to control the thermostat off power to achieve climate control.