Why you might need to do this
While the HE3D printers come with the software pre-flashed, you might want to change settings. This could be anything from wanting to use a special probe that you position under the nozzle of the extruder, to simply changing the rate that settings change when you twist the knob on the front panel.
What you need to start with
- You should get a configuration.h file from the same model of printer you have. That is, if you have a K200, get a K200 configuration file. If you have a K280, get a K280 configuration file. Look in the files section of the Facebook Group or ask there if you can't find one.
- You should back up your EEPROM settings. If you have Repetier Host you can simply ask Repetier to export the settings after typing ALT-E to bring up the EEPROM adjustment menu. If you are using an Octoprint console, then issue an M205 command and capture the output of that command. While reflashing your firmware is not supposed to blow away the EEPROM settings, it would be good to be able to restore things if this does not work.
Getting the ARDUINO code
There are two types of boards that come with the software used by the HE3D printers. One type is an actual Arduino board with a RAMPS piggyback board that further has motor driver boards attached which are used to drive the motors and heaters, and the other is an MKS board that is a combination of both boards on one PCB, with everything pre-installed.
In either case, they are controlled by Arduino software. You can download the arduino software from https://www.arduino.cc/en/main/software and you should install it. Now, I want to be clear. The arduino software is basically a compiler - it converts source code written for the Arduino into object code, and then uploads it to the Arduino. Follow the instructions on that site to download the software for your system.
Modifying your configuration.h
One of the many things that is good about the Repetier firmware is the online configuration tool. Getting the full version of the Repetier software happens as a result of using the online configuration tool. This is a link to the 0.92.9 version of the configuration tool, at https://www.repetier.com/firmware/v092/. Unless you have a reason, use the most current stable version of the tool.
The first thing you should do is to upload your configuration.h to the tool. Then press Next Step. The configuration tool will lead you through a series of menus and choices. If you change things randomly, your printer might malfunction, but if you know what you are doing, and just change certain things, this works well.
As the last step, the Repetier online configuration tool will tell you that it will download the configuration.h file it has prepared for you. It will also offer you a copy of the whole Repetier firmware suite. The first time, take everything. After that, it is your choice whether to take just the configuration.h or the whole firmware download.
If you have taken it all, download the file and unzip it.
Building the Repetier Firmware
You have two choices when you build. One is to compile and upload and the other is just to compile. You probably want to compile and upload. Make sure that your Arduino is attached to your computer via the USB cable. Make sure that Repetier is not connected to the board. Using the same port that Repetier uses and the Arduino tools menu, set the board and port if needed.
Now find the repetier.ino file that you downloaded. It should be associated with the Arduino program. Open it
At this point, you should be completely ready to go. Use Sketch->verify/compile to compile only, or Sketch->Upload to compile and upload. Unless you are changing things outside of the configuration.h it is unlikely that there is any advantage to compiling without uploading.
Using Repetier-Host or Octoprint, verify that no settings are changed in the EEPROM.
And that is it.