Yesterday i got my Arduino-DAC-galvoscanner experimental setup working. Wow! I used an Analog Devices AD5732R DAC on a breadboard, no other components needed (though one should definitely add some decoupling capacitors). In hindsight i should've choosen the AD5734R version with 4 output channels instead of 2, the bipolar signal requires 2 DACs per channel, two channels equals four DACs, obviousby nastybyte - Polymer Working Group
I looked at the Lasershark project and its opensource but is only 12 bits, has more features than i need, and since i already have a show card i think i can get what i need (a simple DAC) for a fraction of the cost. It just means i have to learn how to build one, which, after all, is a good thing! Disregarding the reasons i can take count of the fact that a bipolar analog signal (one signal inby nastybyte - Polymer Working Group
Today i got the galvo to move! The "show card" did not have a USB connection, only ILDA, which means a digital to analog converter is required between the computer and the show card. I had no idea of this when i placed the order... The ILDA standard is eh...not very modern, it seems to me. Instead of talking serial or something you're expected to feed the controller bipolar analog signals (-5by nastybyte - Polymer Working Group
Maybe i should state my question more clearly. Assuming a perfect laser, what properties of the galvanometer scanner will affect the final laser spot quality and its movement? Things i can think of: * Quality & suitability of mirrors: wavelength compatibility, adequate intensity tolerance, what more? * Coils & magnets: haven't studied this much but i read about the guy who built his ownby nastybyte - Polymer Working Group
Thanks for the link, i'm reading through that thread right now. Exactly the kind of info i wanted! But, the problem you mention is caused by the laser, not the galvo? I have a lot of reading and questioning to do before i can even start considering what laser to use - i've come to understand that it is quite a topic...by nastybyte - Polymer Working Group
I'm on the verge of ordering a 2D laser galvanometer from China: EBay. The seller says that the mirrors should be OK with 405 nm lasers, and it has a USB connection and an ILDA connection, i'm guessing the "show card" takes the USB and outputs ILDA. ILDA is an open standard so it should be no problem (more than the work involved) implementing an opensource driver card. Or one figures out how to cby nastybyte - Polymer Working Group
It seems reasonably priced galvo systems can be found: EBay, though they could have given some more info on how to interface to the thing... Next step would be the laser. 405 nm is the thing we want, right? Collimate, or focus to a specific distance? Focus optics seems a bit complicated, but required for good resolution...?by nastybyte - Polymer Working Group
Ok, a DLP printer would be much simpler, but would have a very limited build volume and also a definite limit to resolution. A galvo-based laser system, possibly with more than one laser, would greatly overcome these limitations, and - at least in theory - be even cheaper to build. Sounds like a challenge to me! There's one thing i don't understand: whether you're working from top or bottom, thby nastybyte - Polymer Working Group
I haven't decided anything yet but it seems to me that laser is the way to go. However, i'll need some kind of instruction to follow for the build - laser optics, circuit design and programming are not my areas of expertise. I can think of a number of reasons for choosing the laser-based design: * Cost. I have a lot of time, but correspondingly little (no) money. * Intensity. * X,Y Resolutioby nastybyte - Polymer Working Group
For a UV-curable resin to be suitable for 3D printing i guess the critical property must be how photosensitive it is, to maximize print speed. I'm a chemist by profession but i haven't any experience with polymer chemistry, and i think i'd like to read up on the subject. What mechanism(s) cause a material to photopolymerise, and how would one optimize this behaviour? I've read some very interestiby nastybyte - Polymer Working Group
Hello, i've built a reprap and i love it! However, now that i've started learning to model my own 3D objects i've realized how limited the machine actually is. A DLP printer seems to be the obvious next step (right?). Are there any published open-source designs, working software (i'm not a software guy)? Let's make this thread a list of projects! But please, no crowdfunding projects without anyby nastybyte - Polymer Working Group
Jag har precis fått min att funka tillräckligt bra, den står just nu och test-skriver ut delar till en i2. Utskriftskvalitén är inte 100%ig än så du kan få de riktigt billigt om du vill. Funktionen borde det inte vara nåt fel på, isf ersätter jag förstås. Bor du i Götet? Jag beställde elektronik och specialdelar (heatbed, stegmotorer, linjärlager mm) från (frankrike). Företaget verkar jättebraby nastybyte - Sweden, Gothenburg RepRap User Group
Hah, it really was that simple! Now i have some calibration to do.by nastybyte - Printing
I admit i have to read up on what that even means, but i've set the "g-code flavour" option to "teacup" in slic3r...by nastybyte - Printing
Hello, i've just finished my prusa i2 build and yesterday i did my first try at printing something, namely the bed levelling calibration thing. After adjusting endstops and microstepping settings to get the thing onto the printbed everything seems more or less OK until it gets to a rounded corner, when the extruder starts spinning like crazy! Any ideas why it might be trying to extrude so much sby nastybyte - Printing
To be honest, i don't have a clue how to calculate a good value for those capacitors, just plugged it in and it happened to work (i guess that consumed a good deal of luck, hopefully well used). Bought a new 20 MHz crystal and now i can upload firmware from Arduino IDE, and even connect with pronterface. Whee! For the record, i also had to replace a coil with a plain wire to get the board to woby nastybyte - Next Wave Electronics Working Group
It's blinking!!! It must be the clock crystal that's broken - i de-soldered it and replacing with the 4 MHz one, and it works! I also get data on the serial, no readable text but i guess that is to be expected with the wrong clock frequency. Thank you so much for all the help!! I hope i'll be able to help someone in return!by nastybyte - Next Wave Electronics Working Group
Yeah, i guess that would be very useful to try to find out what's wrong with the board. Just tried writing that .hex file to the chip, avrdude reports no problems but after a reset the chip give no signs of life, neither on the breadboard with 4 MHz crystal nor on the gen7 board. The .hex file should be written to flash (avrdude -U flash:w:whatever.hex), right? I guess that overwrites the bootloaby nastybyte - Next Wave Electronics Working Group
OK, sounds and seems the ArduinoISP programmer doesen't work very well! I finally managed to burn the bootloader using a parallel programmer and a really old computer with a real honest to god parallel port. Programming on the gen7 board did not work (timeout like no connection) but when i had it on a breadboard with a 4 MHz crystal i found, avrdude was finally happy. Now i'm trying to do a serby nastybyte - Next Wave Electronics Working Group
I've checked the resistance between each ICSP terminal and the respective pin on the atmega, each is <1 ohm. I also looked at what happened on the pins when running avrdude with the scope: !RESET: high, goes low for a noticeable period when avrdude is executed. SCK: low, but i can see some signal blinking shortly after avrdude is executed. MISO/MOSI: i think i saw something flashing here tby nastybyte - Next Wave Electronics Working Group
Ah, got a little worried there - 10 & 11 are GND & +5V. A common GND is good, i thought as much, but +5V? I think i read somewhere that one should not interconnect different power supplies like that.. I tried connecting the scope to the XTAL pins and had expected to see something wave-like or just two lines if it's too fast, but there's only one line - direct current, no oscillation? Meaby nastybyte - Next Wave Electronics Working Group
ATX power is on, the yellow led is on but there is 0 V between pins 19 & 20. Does this indicate a defective chip? Also, is it good or bad to connect the GND and +5V lines on the ICSP when the target board is independently powered? At least i think my programmer is working correctly, just verified using another arduino.by nastybyte - Next Wave Electronics Working Group
I think at least one of my problems is with the programmer, right now its "not responding" at all (non-reproducible, a few days ago it definitely worked since i managed to burn a bootloader to a blank m328). Guess the best place to get that sorted out is the Arduino forums, so i'll post a thread there. I do have a scope (an old beauty found at a second hand store, it has vacuum tubes in it! ), anby nastybyte - Next Wave Electronics Working Group
Thanks for the answers! I took the sync errors at baud rates != 19200 as an indication that the wiring is fine...correct? Oh, i forgot to mention i'm running the latest stable Arduino release 1.0.3 on Ubuntu 12.10. When i connect an ATX power supply, the green on/off led lights up but dies out after a second or two, the yellow standby led lights up and stays on.by nastybyte - Next Wave Electronics Working Group
I'm trying to burn the gen7 bootloader to an atmega644, using an arduino as ISP. After many hours of searching and trying, i managed to get a bootloader onto another Arduino, with the programmer attached to the ICSP connector. However, hooking the same setup to my gen7 board, switching board in Arduino IDE and trying to burn the bootloader it says that the device ID is 0x000000. Avrdude from theby nastybyte - Next Wave Electronics Working Group
Hello, i've just started building a prusa i2, and i've noticed that the printed parts for the extruder on the prusa build instruction page is quite different from those shown on the build instruction for "wade's geared extruder". For example, the idler on wade's page is fastened by 4 bolts, but the one pictured on the i2 page only has 2, and - i suppose - some other form of tightening mechanism.by nastybyte - General Mendel Topics