Microcontroller-based DAQ System

A microcontroller-based DAQ uses a microcontroller as the central unit to acquire, process, store and transmit data. It is compact, low cost, low power and portable.

Hardware organization

Block	Role
Sensors	Convert physical quantity to electrical signal
Signal conditioning	Amplify, filter, isolate
Multiplexer	Selects among several channels
ADC	Digitizes the signal
Microcontroller	Controls sampling, processing, scaling, logging
RTC	Adds timestamps
Memory	Stores data (SD card, EEPROM, Flash)
Display / keypad	Local user interface
Communication	Sends data to PC (UART, USB, SPI, I2C, Bluetooth, Wi-Fi)
Power	Battery or regulated supply

Working

1. Timer triggers sampling at fixed rate.
2. MCU selects channel and starts ADC conversion.
3. The result is scaled, filtered and time-stamped.
4. Data is stored and/or sent to the PC.

Advantages

Low cost, portable, programmable, flexible and expandable. Limitations: limited speed and memory compared to PC-based DAQ.

Exam tip

Draw the block diagram with MCU at the centre and explain the 4 working steps.