68 lines
2.3 KiB
Markdown
68 lines
2.3 KiB
Markdown
# Hall filament width sensor
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This document describes Filament Width Sensor host module. Hardware used for
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developing this host module is based on two Hall linear sensors (ss49e for
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example). Sensors in the body are located on opposite sides. Principle of operation:
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two hall sensors work in differential mode, temperature drift same for sensor.
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Special temperature compensation not needed.
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You can find designs at [Thingiverse](https://www.thingiverse.com/thing:4138933),
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an assembly video is also available on [Youtube](https://www.youtube.com/watch?v=TDO9tME8vp4)
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To use Hall filament width sensor, read
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[Config Reference](Config_Reference.md#hall_filament_width_sensor) and
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[G-Code documentation](G-Codes.md#hall_filament_width_sensor).
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## How does it work?
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Sensor generates two analog output based on calculated filament width. Sum of
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output voltage always equals to detected filament width. Host module monitors
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voltage changes and adjusts extrusion multiplier. I use the aux2 connector on
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a ramps-like board with the analog11 and analog12 pins. You can use different pins
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and different boards.
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## Template for menu variables
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```
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[menu __main __filament __width_current]
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type: command
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enable: {'hall_filament_width_sensor' in printer}
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name: Dia: {'%.2F' % printer.hall_filament_width_sensor.Diameter}
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index: 0
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[menu __main __filament __raw_width_current]
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type: command
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enable: {'hall_filament_width_sensor' in printer}
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name: Raw: {'%4.0F' % printer.hall_filament_width_sensor.Raw}
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index: 1
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```
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## Calibration procedure
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To get raw sensor value you can use menu item or **QUERY_RAW_FILAMENT_WIDTH**
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command in terminal.
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1. Insert first calibration rod (1.5 mm size) get first raw sensor value
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2. Insert second calibration rod (2.0 mm size) get second raw sensor value
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3. Save raw sensor values in config parameter `Raw_dia1` and `Raw_dia2`
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## How to enable sensor
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By default, the sensor is disabled at power-on.
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To enable the sensor, issue **ENABLE_FILAMENT_WIDTH_SENSOR** command or
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set the `enable` parameter to `true`.
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## Logging
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By default, diameter logging is disabled at power-on.
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Issue **ENABLE_FILAMENT_WIDTH_LOG** command to start logging and issue
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**DISABLE_FILAMENT_WIDTH_LOG** command to stop logging. To enable logging
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at power-on, set the `logging` parameter to `true`.
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Filament diameter is logged on every measurement interval (10 mm by default).
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