Final Project

In this final project you will be bringing together all your circuit and programming skills into one task.


You will be building adders with IC chips and then have your Micro:bit as the inputs. You will then have LEDS as the output and have to convert the output by hand from binary to decimal. Here is an example:

  • 0 + 0 = 0, 0 -> both output LEDs will be off so answer is 0
  • 0 + 1 = 0, 1 -> sum output LEDs will be on and other off so answer is 1
  • 1 + 0 = 0, 1 -> sum output LEDs will be on and other off so answer is 1
  • 1 + 1 = 1, 0 ->carry output LEDs will be on and other off so answer is 2

You must complete the following circuits and output correctly. Once done you can move forward to the next one. Your mark will be whatever latest one you have completed fully before the end of semester:

  • 1/2 Adder -> Level 1
  • 1-bit Full Adder -> Level 1+
  • 2-bit Full Adder -> Level 2-
  • 2-bit Full Adder 2s Compliment-> Level 2
  • 2-bit Full Adder / Subtractor -> Level 2+
  • 3-bit Full Adder -> Level 3-
  • 3-bit Full Adder 2s Compliment -> Level 3
  • 3-bit Full Adder / Subtractor -> Level 3+
  • 4-bit Full Adder -> Level 4-
  • 4-bit Full Adder 2s Compliment -> Level 4
  • 4-bit Full Adder / Subtractor -> Level 4+
  • 4-bit ALU -> Level 4++

Please note: It turns out the the 3.3V on the Micro:bit does not have enough power (Amperage) to run the IC chips. Due to this you will need to use the power supply with the 9V battery. You can then connect your power supply USB to the Micro:bit. This way they are all connected to the same power source. The "Power and GND" on each IC chip should be connected to the power supply rails on your breadboard and only the inputs coming from the Micro:bit. For a better picture, see the "Half adder in motion" video.

What to submit for each section: For each section you must submit a PDF that includes:

  • your code
  • the truth table
  • a picture of your breadboard
  • and actually show me it working, so I mark it off