Time to get down and dirty with the Marlin firmware for the RAMPS 1.4.
Luckily bq have made the Hephestos firmware avaliable as a well documented github repository, just what you need to get started.
Sourcing the firmware:
As this is a an open source printer, there is no issue in retrieving the firmware used for the RAMPS 1.4 breakout for the Arduino MEga 2560 controller
(13-02-2015: v1.4 of the Hephestos fork released on 10-02, link above now links to V1.4, the changes below still stand.)
Modifying the firmware:
Change Those Settings:
#define TEMP_SENSOR_BED 1
The value 1 is uesd because i am using 100Kohm thermistor, you can specify other values that are indicated in the well commented configuration file.
#define X_MAX_POS 215
#define X_MIN_POS 0
#define Y_MAX_POS 180
#define Y_MIN_POS 0
#define Z_MAX_POS 170
#define Z_MIN_POS 0
These were set to define my print area.
I have lowered the Y Max Pos to 180 mm, from 210 mm, as the bed kept slamming into the end-stops.
I have lowered the Z Max Post to 170 mm, from 180 mm, because the print head returns to the very top position and as i have raised the print bed by nearly 1 cm, including the z-stop, this change stops the printer from overshooting the top end of the z-axis
I found it helpful to send the print-head home then use the jog dial to indicate the values used.
You can also change a couple of lines in language.h to name your printer; I chose to name mine Salti Heph.
Compiling the firmware:
- Grab yourself the older version of the Arduino IDE, The repository we are using recommends Arduino 0023
- Download and unpack the IDE files
- Download and unpack the Marlin Source Code
- Start the IDE and load the Marlin.ino
- Select Tools > Board > Arduino Mega 2560
- Select Tools > Serial Port and take note of what is currently available.
- Connect the Arduino to your computer via USB, be sure to power the Arduino directly (not just off USB)
- Select Tools > Serial Port and select the new one.
- Hit the “Play” button just under the file menu to Verify and compile your code.
- Last step, upload your firmware to the device and wait for the upload to complete.
Having selected a better model from thingverse.com it was time to test that heatbed… again.
I started the printer and saw the LCD startup show “Salti Heph,” good start!
I then started the print of the model and saw the display change to “Bed Heating” and then BOOM! red light on front of the heatbed with temperature rising.
Startup time is a little longer while you wait for the heatbed to warm up but boy oh boy does that filament stick to the heated glass.
- Change the longer screws for ones that can be turned with Alan Keys/Hex Keys: This is to make levelling the bed easier as it is very hard to use a standard screwdriver when the print head is in the way.
- Replace the M4 nuts with washer stack or cut tubing
- More thought out secondary support layer of cork to allow for clamps