jamesdanielv Wrote: ------------------------------------------------------- > is this the forum for that? yes.by madscifi - Firmware - experimental, borrowed, and future
Jamesdanielv, I think the chipkits are nice boards that are very inexpensive given the capabilities of the hardware. However, I still have concerns about their software. They've certainly oversold their compatibility with Arduino and I've not seen any movement on an opensource c-library. What bothers me most is that they seem to be mostly ignoring questions about the topic on the chipkit forum.by madscifi - Firmware - experimental, borrowed, and future
By "this" I assume you mean this firmware? It's not dead, but I have not had time to do any significant work on it recently. Although the approach used in the firmware to generate the stepper pulses has some technical advantages, I think the approach used by EMC and some other firmwares (single high speed constant interrupt driving all axis) probably makes more sense as it simplifies handling accby madscifi - Firmware - experimental, borrowed, and future
I've pretty much stalled for the moment on this project. I have things I'd like to try out, but I'm not certain when that will I'll get back to it. I'm not aware of any other ongoing work by anyone else on the subject at the moment. Hopefully I'm wrong and someone will correct me. On a related issue Johnrpm has been working on a powderbed design.by madscifi - Powder Printing and Selective Laser Sintering
ABS and PLA do degrade rather quickly in UV - try putting a piece outside in the sun for a couple of weeks. I suspect enough UV to melt the plastic will cause problems, but that suspicion is not based on any hard evidence.by madscifi - Plastic Extruder Working Group
A lot of those salts are rather poisonous, and most are sensitive to water (the water content of the plastic (and air, really) will quickly ruin the nozzle). Silicon or germanium look like they might be plausible candidates.by madscifi - Plastic Extruder Working Group
That is true - I did overstate the case. IR fused silica only allows .2 to 3.5 microns or so to pass, so it would allow a significantly wider region of IR to pass than glass. I don't know whether or not that is sufficient to do what ElectricMucus suggests. I only meant to suggest a material that should work better than normal glass. Edit: Well, it turns out that normal soda lime glass allows .3by madscifi - Plastic Extruder Working Group
IR grade fused silica would allow the IR to pass.by madscifi - Plastic Extruder Working Group
I would certainly be interested in an inexpensive visible-light curable product. It is the possibility of printing very high resolution objects that makes it attractive. However, at the moment I cannot envision any realistic scenario where I would want more than a couple of liters a year.by madscifi - Polymer Working Group
Those samples look good. What layer height are you using? I have not used anything smaller than a 0.4mm nozzle so I don't have anything useful to contribute at this time.by madscifi - General
I suspect that the clay will have to be too wet when extruded from a syringe to make a good support for PLA . However, I plan to try some experiments as soon as I get all of the necessary equipment.by madscifi - General
I've been playing around with the idea of using clay as a manual support material for PLA, and I've written up an page on the Wiki that describes the process.by madscifi - General
See this thread. You may be able to eliminate the problem by adjusting belt tension. If not, one approach to solving the problem is to use a toothed idler pulley. It does appear to improve the situation significantly. I ended up replacing the 5 mm belt with a 1/4 inch wide MXL (0.08 inch, 2.032 mm) belt and used a commercially made pulley. An extra washer was added to each idler bearing assembby madscifi - General
The air pump sounds like an good idea, actually. Another idea to consider is limiting the chamber so that it encloses only the nozzle of the extruder (use a turkey bag or similar to define the upper surface of the chamber). I think the first mention of using a turkey/duck bag is in a post by Adrian. See here.by madscifi - Mechanics
Pearce, that is the kind of information that is not generally available, sadly. Basically, you'll have to ask the maker of the print head or reverse engineer the signals on a working printer.by madscifi - Powder Printing and Selective Laser Sintering
On microcontrollers that supports 4 or more output capture style hardware units (Pic32 and some ARM, probably others as well) it is possible to generate the leading edge of the step pulse from a hardware comparision of a high resolution timer with a changable value. A similar approach can be used with an XMOS chip by dedicating a thread per step generator. On such microcontrollers the timing forby madscifi - Firmware - experimental, borrowed, and future
Which temp sensor are you using?by madscifi - Firmware - experimental, borrowed, and future
rebecca.palmer - thanks for the references. I was not aware of the two PIC32 firmwares you've listed. I believe that Microchip/Diligent's plan is not to open source the current PIC32 libraries but to provide new open source libraries in conjunction with the Multi-platform version of the Arduino code. But, we shall see if they follow through.by madscifi - Firmware - experimental, borrowed, and future
Triffid_Hunter - Thanks, I'll take a look. I'm not quite at the stage of wanting to stop worrying about floating point operations outside of interrupts, the Pic32 chips are not quite that fast, but it is one of the things I plan to do some timing tests on. jamesdanielv - 8 bit pics certrainly could run a RepRap. One of the reasons, i think, that there has not been a lot of work done with them inby madscifi - Firmware - experimental, borrowed, and future
EMC certainly can and has been used to run Reprap machines reliably. However, once you start using acceleration you'll run into print defects due to the fact that there is a significant delay between applying a change to the filament feed and seeing the change reflected in the extruder's output. Matthew Roberts has done some work to address this problem (See here).by madscifi - General
I've started a new firmware project designed for Pic32 microcontrollers, specifically the ChipKit Uno32 board. It is hosted on github and can be downloaded from here. The code is largely a derivative of Teacup but it is no longer strictly C code. The step generation code is completely new and it uses the output capture hardware on the Pic32 chip to generate the step pulses in order to reduce jiby madscifi - Firmware - experimental, borrowed, and future
What values are you using for STEPS_PER_MM_Z and MICROSTEPPING_Z? If the result of STEPS_PER_MM_Z*MICROSTEPPING_Z is greater than 1000 then Teacup will ignore the max setting.by madscifi - Firmware - experimental, borrowed, and future
What version are you running? I have seen Teacup send a stepper off into the wild blue yonder, but not for a long time (I don't remember what version it was). Also, can you post up your config file, that might, or might not, contain some clues? If you have not tried the latest in the master branch on github please do try it out.by madscifi - Firmware - experimental, borrowed, and future
A couple of 64 bit operations (48 bits even) and this would be easy to resolve. Sadly, 64 bit operations on an atmega are extremely expensive. Just out of curiosity I coded a 64 bit conversion using long long to steps and another back to um. It added almost 5000 bytes to flash and over 200 bytes to ram. I did not bother looking at the execution time. I was wrong about the use of the requested umby madscifi - Firmware - experimental, borrowed, and future
Some of us peanuts should pay more attention... Thanks for pointing that out. I'll just state the obvious and point out that best way from an accuracy point of view would be to write an appropriately scaled steps_x_to_um function and use that to convert dda->x_delta to um for use within the function. However, that is relatively expensive and I don't know if it would really be worth the executby madscifi - Firmware - experimental, borrowed, and future
Traumflug, I've taken a look at the patch and I believe it solves the drift problem (although I've yet to actually run the code). However, I think that all uses of x_delta_um in the dda_create function should be replaced by dda->x_delta * UM_PER_STEP_X. My argument is that the distance and limits should be calculated based on the actual motion of the machine, not the requested distance in um.by madscifi - Firmware - experimental, borrowed, and future
The Uno32 chipKIT board looks like a really good candidate as a target for porting Teacup. The cost is currently slightly less than that of a Arduino UNO and it has more io pins available. The only real downside looks to be that is runs on 3.3 volts - the base Pololu boards support 3.3 volts so the only question is whether or not the heater mosfets can be adiquately turned on by 3.3 volts. Whatby madscifi - Firmware - experimental, borrowed, and future
Traumflug, consider what happens when one issues a long series of x-axis only moves, each move only one quarter of a step in length. The internal position tracks to the precision of the math as the series of moves is executed, but since the delta in micrometers from one move to the next is always below that required to issue a step the x-axis never physically moves.by madscifi - Firmware - experimental, borrowed, and future
It's not exactly well tested yet, but one has to start somewhere. I'll pull a copy and start running in on my machine. Does anyone have any suggestions on a good way to track which configurations are known to work reliably?by madscifi - Firmware - experimental, borrowed, and future
I'd like to lend support to Sublime's suggestion that there should exist a well tested stable branch (or tags, or snapshots).by madscifi - Firmware - experimental, borrowed, and future