The Differences Between Analog and Digital Inputs

Once upon a time .. long long ago .. Mr. Widmer bought his first car.  Cars were very simple electrical and mechanical devices.  Their electrical control systems for windscreen wipers ( for instance ) were all analog controlled.  Cars in 2021 use much more electrical and mechanical systems.  We are moving into an era where we won't even drive the car.  It is important to understand how each little change in each new car model produces significant change in our lifetimes.  Analog systems have been replaced by purely digital systems.

A way to understand this shift from analog to digital is to look at the wiring harness of a car.  If you want to turn on the lights on an old car, there is a wire that connects the light switch to each light.  The more electrical devices you fit into an old car .. the more you needed to run another wire!  European car engineers developed a technology that used less wire.  This technology was called CAN bus.

Please read this week's Tasks and Activities.

  • The picture here shows a wiring bus that you find in cars made before 2000.
  • Since 2001 CAN bus has been compulsory in vehicles sold in the European Union .. the USA was slower to adopt this standard.
  • CAN bus uses less wire but requires each connected device to pick up their signal .. this is just like a student listening to the roll call at the start of the class.

 
  • Here is the photograph of a cable shown in class.  It has 50 separately insulated copper wires.
  • This type of cable was very common when connecting a computer to CDROM and Hard Disk drives.
  • It is cheaper to use less wire but the signal ( on/off for example ) must be understood by the device connected to the wire.
  • Melbourne University teaches a Bachelor of Science subject called "Mechatronics".
  • They require their students to build devices that use both analog and digital control systems.
  • Would you like to study that subject at Uni?

Tasks and Activities

  1. What is a "wiring harness" in a car?
  2. What is CAN bus?
  3. When did CAN bus start replace large wiring harnesses?
  4. Use the Internet to give a different example of analog and digital controls than the one discussed in this lesson.
  5. What do you study if you enrol in a subject called "Mechatronics"? ( Hint -- Look at the Uni Melb website. _

 

  

Don't forget to email your choices/answers to Mr. Widmer by the end of this week.  Keep a copy of that email in your Google Docs folder.