- Station for PTC based soldering irons -
Building from source files
A pre-build HEX-File for programming the controller is included within the project files. If you want to build the firmware from the sources, you will need WinAVR and AVRStudio4 which are both free. Make sure that you use the right fuse settings also described in main.c.
Changing the firmware
It will probably be necessary to reverse the direction of the encoder in the software depending on the encoder type used. Please refer to the project documentation for details.
If you want to use another iron, calculate the offset and slope of the PTC heating element by doing some measurements at different temperatures of the iron. Then change the values of the "Slope" and "Offset" constants. The Atmel ATMega8 also measures (at its pin 28) the value of a resistor within the connector of the soldering iron. I think it is used to determine, which iron is connected to the station. You can change the firmware by adding irons with different sense resistors to the "GetSolderIronType" routine and by using different values for "Slope" and "Offset" for specific irons.
You will probably have to measure the value of the reference voltage at pin 21 of U1 and change the value of the "VRefMV" as the internal reference of the ATMega8 is not very accurate in its absolute value.