Analog to Digital Conversion

Contributors: Nate

The Analog World

Microcontrollers are capable of detecting binary signals: is the button pressed or not? These are digital signals. When a microcontroller is powered from five volts, it understands zero volts (0V) as a binary 0 and a five volts (5V) as a binary 1. The world however is not so simple and likes to use shades of gray. What if the signal is 2.72V? Is that a zero or a one? We often need to measure signals that vary; these are called analog signals. A 5V analog sensor may output 0.01V or 4.99V or anything inbetween. Luckily, nearly all microcontrollers have a device built into them that allows us to convert these voltages into values that we can use in a program to make a decision.

Here are some topics and concepts you may want to know before reading this tutorial:

• Voltage, Current, Resistance
• Binary
• Analog vs Digital
• Arduino analogRead()
• Voltage Dividers
• Digital Multimeter
• Powering Your Project