A PicAxe programming and hardware construction exercise for students.
This project is based on the PicAxe 28X2 microprocessor and a SparkFun Geiger tube circuit (now obsolete). Using the PicAxe-28 Project Board is the simplest method to create a circuit for the counter. The microprocessor drives an OLED and an analog meter in order to display the count rate of a Geiger tube. The scale is self-selecting within the program. The hardware is laid out, soldered together and assembled onto a breadboard. Then the program is written and downloaded onto the microprocessor.
The Project Board and the Geiger tube circuit are mounted on a breadboard along with the OLED and the analog meter. A line of LEDs is used to indicate the analog meter scale.
The overall scheme of the software program: count the events in the Geiger tube and display the counts-per-minute on both the OLED and the analog meter.
The basic technique: count the events over sequential four second periods and store the running sum in a wordvariable and send to the displays. Update the count every four seconds.