Where's the microcontroller? I think you want a controller rather than just a driver, looks like there's no microcontroller in either of those. See , note that it has its own microcontroller, a pic16Fsomething. Also see , note that the arduino (atmega168 microcontroller) provides the proper signals for several stepper motor drivers.by Triffid_Hunter - Controllers
I think the amount of glycerine controls the texture. no glycerin = hard and brittle, lots of glycerin = rubbery and flexible.by Triffid_Hunter - Polymer Working Group
) A salt, in chemistry, is defined as the product formed from the neutralisation reaction of acids and bases. Ammonium can be a cation instead of a metal, and most of the anions aren't metallic. So, while most salts are metallic, not all are. Sometimes I wish I'd done more chemistry in school...by Triffid_Hunter - Polymer Working Group
Sodium Chloride (NaCl, common table salt) is also a metallic salt, since sodium is a metalby Triffid_Hunter - Polymer Working Group
can make plastic from starch too.. see (step 3 has the recipe)by Triffid_Hunter - Polymer Working Group
Don't bother trying to solder. The wire will get hotter than solder's melting temperature and solder doesn't stick to nichrome very well, so soldering is both futile and dangerous. Instead, crimp them. Some copper or brass thin walled tubing should do nicely if you don't have anything more suitable lying around. I use my wirecutters to crimp stuff like that. Remember that the wires you attach tby Triffid_Hunter - Controllers
My multimeter's display has 3.5 digits - that is, 3 full digits and a "1". Therefore, it can only show me the 4 most significant digits of any reading. So, when set to 2000v, if I measure 1v, it'll (probably say) 1, whereas on the 2v range it'll say 1.013 or something. Clearly, using the lower range gives me more precision. However, every digit has its own decimal point, and that point will alwaby Triffid_Hunter - Controllers
Has anyone tried using a rolamite bearing for any parts of the reprap? See for detailsby Triffid_Hunter - Mechanics
The 555 has a reset pin, and its frequency stabilises almost on the first cycle, so polling every so often should still work fine. Like this: R2 limits the self-heating of the thermistor, and since the duty cycle will (asymptotically) approach 50% as the thermistor's resistance drops, we get two measurements to use. C1 can be adjusted to suit whichever frequencies work best for the code.by Triffid_Hunter - Controllers
How about using a 555 oscillator with the thermistor as one timing resistor? With a low enough capacitance, it would run at quite a high frequency and allow us to simply put a lowpass on the output to get the analog voltage, although counting cycles with the microcontroller would be far more accurate, especially at lower frequencies. Also, we wouldn't have any problems with very low resistancesby Triffid_Hunter - Controllers
The power supplies that drive car audio systems often run at over 100khz, and can provide thousands of watts if necessary, however it probably is quite a bit more complex than wrapping some heater wire around the barrel. See if you do want to try it out I have an arduino on the way, and several printers from which to scavenge partsby Triffid_Hunter - Plastic Extruder Working Group
monoslam should be able to build 3d models of objects if tweaked to give a much higher density of keypoints. see youtube.com/activevision for demos of what it's capable ofby Triffid_Hunter - Plastic Extruder Working Group
Hi, Has anyone considered induction heating for the extruder? I'm interested to see if wrapping 50 to 200 windings around the head and passing 20vac or so through it generates enough heat in the extruder... 12Vac@1A / 50 windings = 0.24Vac@50A around the circumference of the barrel. Common switchmode chips like the tl494 and sg3525 could probably be used to regulate the temperature. Perhaps wby Triffid_Hunter - Plastic Extruder Working Group