Sensor reading through ADC (temperature, light) in Embedded C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is ADC in embedded systems?

ADC stands for Analog-to-Digital Converter. It changes analog signals, like temperature or light levels, into digital numbers that a microcontroller can understand.

beginner

Why do we use sensors like temperature or light sensors with ADC?

Sensors output analog signals that vary continuously. ADC converts these signals into digital values so the microcontroller can read and process them.

intermediate

What is the typical process to read a sensor value using ADC in embedded C?

1. Initialize the ADC hardware.<br>2. Start the ADC conversion.<br>3. Wait for conversion to complete.<br>4. Read the digital value.<br>5. Convert the digital value to a physical unit like °C or lux.

intermediate

How do you convert an ADC digital value to temperature?

You use the sensor's datasheet formula. For example, if the sensor outputs 10mV per °C and ADC reference is 3.3V with 12-bit resolution, calculate voltage from ADC value, then divide by 0.01V to get °C.

beginner

What is the role of reference voltage in ADC readings?

Reference voltage sets the maximum voltage the ADC can measure. The ADC value is proportional to the input voltage divided by this reference voltage.

What does ADC stand for in embedded systems?

A Automatic Data Controller

B Analog-to-Digital Converter

C Analog Data Calculator

D Advanced Digital Circuit

ADC means Analog-to-Digital Converter, which changes analog signals to digital numbers.

Which step is NOT part of reading a sensor value using ADC?

A Initialize ADC hardware

B Start ADC conversion

C Read digital value

D Convert digital value to analog

ADC converts analog to digital, not digital to analog.

If an ADC has 12-bit resolution, what is the maximum digital value it can output?

A 1023

B 65535

C 4095

D 255

12-bit ADC outputs values from 0 to 2^12 - 1 = 4095.

Why is reference voltage important in ADC?

A It sets the maximum input voltage the ADC can measure

B It powers the sensor

C It controls the sensor's output

D It converts digital to analog

Reference voltage defines the max voltage the ADC can convert.

What type of signal do temperature and light sensors usually output?

A Analog signals

B Digital signals

C Binary code

D PWM signals

These sensors output analog signals that vary continuously.

Explain the steps to read a temperature sensor value using ADC in embedded C.

Think about how the microcontroller talks to the ADC and sensor.

Describe why ADC is necessary when working with light sensors.

Consider the difference between analog and digital signals.