Currently working on the electrical wiring and Arduino control of my penultimate year group project in Design Engineering. We're recycling milk bottles, grinding them up, heating through a screw, extruding, cooling in water and then spooling.
I'm bound to have loads of questions that learned folk like yourselves would love to answer. I have been working on this aspect of the project since early January so it is progressing, I think!
The extruded filament needs to be 2.9mm +/- 0.1mm. We would love to measure this diameter whilst the extrudate is still molten and therefore untouchable. There are a few methods we are exploring but today photodetector arrays have really gotten me excited (would be sad if I wasn't admitting it here :P), more specifically this one: http://www.active-robots.com/products/parallax/tsl1401-linescan-imaging-sensor-daughterboard.shtml
Reading through the documentation I have found I gather that it is possible to digitally read each one of the 128 sensors in the array in turn converting their voltage into a simple 1 or 0.
How does one go about coding this. At the moment I can imagine having an array that is filled by the sensor readings. How do I then inspect the contents of the array to find the edges of my filament? The idea being that then, with some calibration, I would know if the hot filament was currently too big or small in diameter and speed up / slow down the haul off motor accordingly.
Would really love any help with this, be as brutal as you like about it if it's stupid... :D
Thanks in advance!