Filament diameter sensor

youmagine

This is a prototype filament diameter sensor, designed specifically for an extruder making filament. The filament's centerline is positioned 90mm above the mounting surface. It detects the filament's diameter between two bearings and amplifies it by a factor of 3.6 through a lever that moves a magnet in front of the hall sensor. The hall sensor's depth is adjustable and securely locked into place via an M3 bolt. To prepare for use, bend the hall sensor leads 90 degrees to the back and position the sensor in its recessed spot. Then, lead the wires out to the front. A 6x2mm magnet fits neatly into the matching hole on the lever, while a second hole is reserved for a ballpen spring, which is typically unnecessary. To test the sensor, upload the included sketch to an Arduino board and connect the hall sensor to 5V, ground, and attach its signal pin to A1 on the Arduino. Next, establish a serial connection at 115200 baud and you'll receive two values per line: the smoothed ADC value and the calculated diameter. To calibrate the sensor, insert a test object with the maximum diameter you want to measure between the bearings, then adjust the hall sensor carriage until the ADC value reaches its maximum point. Secure the carriage in place and use this value in conjunction with the diameter of the object as the final entry in the Arduino's lookup table. Insert additional objects of varying sizes (like drill bit shafts) and complete the lookup table. Use the idle position without any inserted items for the zero-diameter reference point. Note that some files may require support material due to 30-degree overhangs, and if you're using Slic3r, it's recommended to opt out of support material altogether. Unfortunately, the Solidworks source file is quite disorganized, so please bear with us.