Analog to Digital Conversion

Analog to Digital Conversion

Analog vs. Digital

  • Analog: infinite variations / states
  • Digital: discrete (or finite) states
  • How do we represent infinite variations in a system that has limited / finite values?

Analog to Digital Conversion

  • Argon is a digital system so we need to convert the infinite analog input to a discrete values
  • At regular intervals, the Argon samples (“reads”) voltage on analog input pin it sees
    • The sampling frequency is how many times per second
  • The resolution is how many bits are used to store the voltage
    • Higher resolution means greater detail, but also more bits (more memory)

Understanding Resolution

  • Red line is actual analog input voltage (in volts)
  • Blue line is the digital sample value (just a number with no units)

Argon ADC Resolution is 12-bits

  • When we read the analog input voltage, ADC converts the voltage to a number
  • There 2^12=4096 possible values (think “buckets”)
  • In Binary
    • 0 = 000000000000
    • 4095 = 111111111111

Argon ADC

  • The range of analog voltage is 0v to 3.3v
  • The range of digital values is 0 to 4095
  • Q: How many digital values per 1v?
  • Q: How many volts per each digital value?
  • Q: If there is 3.3v on an analog input, what is the value of analogRead()?
  • Q: If there is 1.67v on an analog input, what is the value of analogRead()?



  • Connect potentiometer to analog pin A0
  • Connect LED to digital pin D2 (do we a pin with PWM?)
  • Control LED brightness with potentiometer