7 Segment display + 2 button input

This tutorials covers the following topics;

  • Connecting a common cathode 7 segment display
  • Displaying figures 0-9 on the display
  • Controlling the output using 2 input switches

Unlike previous tutorials, this tutorial will not be using the PICAXE 18X developer board during contruction. THis is due to the Darlington Driver which is fitted in in the board.
A normal 18X microcontroller is capable of both sourcing and sinking current but when it is connected through a Darlington driver IC it is no longer able to source current.
The are 2 variations of the 7 segment display, one which has a common cathode (more common) and the other has a common anode. A common cathode display requires the common pin to be connected to the negative terminal of the power supply. Current is then sourced through the microcontroller to light the relevant sections of the 7-seg display. A common anode version requires the common pin to be connected to the positive terminal and then sinks current into the microcontroller. We will be using a common cathode display in this tutorial and as such will require the microcontroller to be able to source current to the display.


Whats required for the tutorial;
  • Battery Pack
  • PICAXE 18X
  • PICAXE 18X developer board (for programming)
  • Breadboard/Prototyping board
  • Common cathode 7 segment display
  • Two micro-switches
  • Wires/Connectors etc

Start the tutorial