Como hacer un Termómetro que pueda medir de 0ºC a 50ºC
How to Build an Electronic Thermometer
Introduction to the LM35 Temperature Sensor
- The LM35 sensor measures temperatures from -2°C to 150°C, providing a small output of 10 millivolts per degree detected.
- Due to the low signal strength, an operational amplifier is necessary to amplify the signal for accurate readings.
Configuring the Operational Amplifier
- The operational amplifier is set up as a non-inverting amplifier using negative feedback for signal multiplication.
- Resistance values are crucial; for example, using a 3.3kΩ resistor and a 1kΩ resistor results in a gain of approximately four times the input signal.
Testing Signal Multiplication
- After connecting the LM35 directly to pin number three of the operational amplifier and powering it with 6 volts, initial readings show around 240 millivolts at the sensor.
- The output from the operational amplifier reads about 1000 millivolts, confirming that amplification is functioning correctly.
Integrating with Analog Multiplexer (BHU Metro)
- An analog multiplexer divides voltage into ten outputs; prior amplification ensures effective operation within this setup.
- A specific resistance (10kΩ) is connected at one output to manage static and voltage drop issues effectively.
Calibration Process
- To calibrate, replace the temperature sensor with a potentiometer that simulates its output in millivolts; adjust it to represent maximum desired temperature (e.g., 40°C).
- By varying settings on another potentiometer linked to BHU Metro, users can determine when outputs activate based on simulated temperatures.
Final Adjustments and Color Coding
- Calibration allows measurement ranges from 0°C to 50°C; color coding each output helps indicate different temperature levels: red for high, yellow for medium, green for normal, and blue for low temperatures.
- Extend pins from the temperature sensor using single-strand wires for better coverage during detection; labels can be added indicating temperature ranges next to LED indicators.
This structured approach provides clarity on building an electronic thermometer while emphasizing key components and processes involved in its construction and calibration.