MIDIbox Hardware Platform, Motorfader NG Module
The MF_NG module is the successor of the MBHP_MF module and has following design targets:
- find a solution to handle high-quality faders like Alps K faders with "coreless" motors
- find a solution for MBHP_CORE_LPC17 which doesn't deliver stable enough ADC conversion results due to the reduced 3.3V voltage range
- find a solution for MBHP_CORE_LPC17 which cannot handle touch sensors properly without heavy CPU load (resp. without an additional external device or microcontroller)
- find a solution which is compatible with PIC based projects for best usability
- find a solution which is DIY friendly and doesn't require additional gear for something which isn't part of the MBHP yet
- find a solution which can be easily tested and troubleshooted (no need to learn new processes)
And this module is the result:
- a dedicated PIC controller controls the motorfaders directly.
- the firmware can be updated via MIDI!
- motorfaders are accessed via MIDI - this allows standalone usage, cascading (to chain multiple modules), and the re-use of existing infrastructure such as MIOS, MIOS Studio and MIOS Bootloader
- the module can either be connected to a PC directly, or controlled from a second PIC or STM32 or LPC17 (note that MBHP_CORE_LPC17 has a third and even a fourth MIDI IO port at TTL level so that the available two MIDI IO pairs are still free)
- native support of various protocols (e.g. PitchBender, CCs, even Logic Control and Mackie Control Emulation)
- support for 8 touch sensors
- instead of TC4427 I'm using L293D now - not at least because of the integrated diodes.
- due to the direct motor control connections, the PIC is now able to generate PWM with 50 uS steps for improved motor speed control while a motor is moved
- since the firmware is dedicated for this task, there was enough memory free to integrate advanced features, such as runtime-calibration and motor position tracing which are supported by MIOS Studio:
|PCB data, can be viewed, modified and converted with Eagle Light. The .pdf based schematic has been created with xcircuit. There are no special eagle schematics available, since components have been netlisted in the .brd file directly!
More informations (e.g. recommended motor voltages and fader comparison) will follow soon.
Link to Forum Thread
Thank-you goes to SmashTV who created the PCB layout and will provide the Kits in his MIDIbox Shop.
Last update: 2017-02-26
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