07 – Experimenting Circuit for a PICAXE-08M

The School Experimenter Board (AXE092) circuit diagram is an excellent experimenter circuit for the PICAXE-08M microprocessor. With this circuit one can demonstrate the capabilities of the PICAXE-08M in a practical and fun way. 

The full circuit description is available in the PDF document from PICAXE but I will quickly highlight the most important aspects.

Pin No.

Description of the circuit functions

Pin 1

Pin 1 is the +5V Supply.

Pin 2

The 10k and 20k resistors connected to pin 2 is part of the programming circuit for the PICAXE microcontroller and is connected to the serial download socket.

Pin 3

Pin 3 is used as an analogue input with the LDR and the 10k resistor in a voltage divider circuit. With no light the LDR has a high resistance and the input voltage will have a low value. With a lot of light the LDR has a low resistance and the input voltage will have a high value. 

Pin 4

Pin 4 is used as a digital input with a pull-down resistor of 10k. Normally the input will have a low input (push-button’s default state is open) but when the push-button is pressed the input voltage goes to a high.

Pin 5

Pin 5 is used as an output to drive a green LED and a piezo sounder. The 330 Ohm resistor is used to limit the current through the LED within safe limits.

Pin 6

Pin 6 is used as an output to drive a yellow LED. The 330 Ohm resistor is used to limit the current through the LED within safe limits.

Pin 7

Pin 7 is used as an output to drive a red LED and it is also used as the Serial Out pin used in the programming and is connected to the serial download socket. The 330 Ohm resistor is used to limit the current through the LED within safe limits.

Pin 8

Pin 8 is the 0V supply. 

You can construct the circuit on solder-less breadboard or strip-board but obtaining the School Experimenter Board (AXE092k) will probably be the best option to start experimenting.