Reading analog sensors through ADC in Raspberry Pi - Mini Project: Build & Apply

Reading analog sensors through ADC

📖 Scenario: You have a Raspberry Pi connected to an analog temperature sensor through an ADC (Analog to Digital Converter) chip. The ADC converts the sensor's analog voltage into a digital value that the Raspberry Pi can read.Your task is to write a Python program that reads the sensor value from the ADC and converts it into a temperature reading.

🎯 Goal: Build a Python program that reads the analog sensor value from the ADC, converts it to a voltage, and then calculates the temperature in Celsius.

📋 What You'll Learn

Create a variable to simulate ADC raw data reading

Create a variable for ADC reference voltage

Calculate the sensor voltage from the ADC raw data

Calculate the temperature from the sensor voltage

Print the temperature value

💡 Why This Matters

🌍 Real World

Reading analog sensors like temperature, light, or humidity sensors is common in Raspberry Pi projects for home automation, weather stations, and robotics.

💼 Career

Understanding how to interface analog sensors with digital devices and convert raw data into meaningful values is a key skill for embedded systems and IoT developers.

1

DATA SETUP: Create ADC raw data variable

Create a variable called adc_raw and set it to 512 to simulate the ADC raw reading from the sensor.

Raspberry Pi

# Create a variable called adc_raw and set it to 512
# Your code here

Hint

The ADC raw value is a number between 0 and 1023 for a 10-bit ADC.

2

CONFIGURATION: Set ADC reference voltage

Create a variable called v_ref and set it to 3.3 to represent the ADC reference voltage in volts.

Raspberry Pi

adc_raw = 512
# Create a variable called v_ref and set it to 3.3
# Your code here

Hint

The reference voltage is the maximum voltage the ADC can read.

3

CORE LOGIC: Calculate sensor voltage and temperature

Calculate the sensor voltage by creating a variable called voltage using the formula voltage = (adc_raw / 1023) * v_ref. Then calculate the temperature in Celsius by creating a variable called temperature_c using the formula temperature_c = (voltage - 0.5) * 100.

Raspberry Pi

adc_raw = 512
v_ref = 3.3
# Calculate voltage from adc_raw and v_ref
# Calculate temperature_c from voltage
# Your code here

Hint

The sensor outputs 0.5V at 0°C and increases 10mV per degree Celsius.

4

OUTPUT: Print the temperature

Write a print statement to display the temperature in Celsius with the text: Temperature: {temperature_c} °C using an f-string.

Raspberry Pi

adc_raw = 512
v_ref = 3.3
voltage = (adc_raw / 1023) * v_ref
temperature_c = (voltage - 0.5) * 100
# Print the temperature in Celsius
# Your code here

Hint

Use an f-string to include the variable temperature_c inside the print statement.