I just purchased a 3D Chameleon based on the belief that the boards have TMC stepper drivers and that it can do sensorless homing, automatic calibration, etc as per the 2 minute mark in this video:
The board I just received has 4988 drivers.
Did I get an old board or something?
The latest video that I've seen so far.
The Mk4 comes with the stock electronics we've always used... however, we have several open source options that will be available and are supported by the board you have through the I2C interface (indicated by the two white connectors in the lower left) that will allow much more capability than the TMC drivers we initially were trying (that video is several months old and is out of date.) Check out some of the more recent videos of the Rocky Mountain RepRap Fest where we went over a lot of the new features/capabilities. One of those options is an AS5600 based Rotary Motor Encoder that will attach to the extruder motor to track it's motions. This will allow us to close loop control the motor along with detect "passive movements", for example, when the filament is inserted, as well as detect the extruder's drive gears, when the extruder is pulling as well as where the Y adapter is located physically, so that autocalibration can happen.
All of the Mk4 Pro accessories will be 100% open source and freely available to anyone who wants to install it on any previous version of the 3DChameleon, which is why we didn't physically change the board or the drivers.
Moving to the I2C expansion bus, also allowed us to design an entirely new architecture in the software that allows for even more expansion capabilities, like additional I/O for filament runout, an OLED display and many other options in the future.
We'll be posting information about some of the first expansion extensions soon as well as detailed instructions, bill of materials and all necessary hardware models to support them.
Stay tuned...
Bill