if the only difference is the 2nd uart, you should be able to replace all occurrences of USART0 with USART in the firmware, then recompile and run. If you find an occurence of USART1, you may need the 2nd uart after all. avr-libc calls them USART0, USART1, etc when there's many, but just USART if there's only one. You could potentially even redefine USART0* USART* and compile successfully, and yby Triffid_Hunter - Controllers
wesjanik: you're not missing anything - the ethernet cable is carrying power that it can only carry for a short run through free air (and even then it's marginal at best). ensconsed in a wall it would definitely be a fire hazard. I'd personally prefer to run power through a drive molex like all the other boards. lists the maximum current per conductor at just above 0.5A, so that's a mere 1.5Aby Triffid_Hunter - Controllers
the stepper driver v2.3 uses the A3982 driver chip. this chip supports full step and half step. the v3.0 stepper drivers from makerbot use the A3977 chip which has built-in 1/8th stepping. I'm redesigning this board at the moment to accept the TSSOP28 package of this chip, which is significantly cheaper as well as pin-compatible with TI's DRV8811by Triffid_Hunter - Controllers
Microstepping doesn't technically provide more torque, but it does give you smoother movement an less likelihood of slipping when torque is required, so below the motor's regular stall torque, it *behaves* like it has more torque. there's also mid-band resonance to take into account. This is where, at a particular speed, your torque drops to almost zero due to various resonance effects. I read tby Triffid_Hunter - Mechanics
my mendel will use ball chain because the timing belts are too expensive here for reasons unknown to meby Triffid_Hunter - Reprappers
More as a note for myself than anything, but do comment here if you have thoughtsby Triffid_Hunter - Controllers
just fyi, makerbot's v3 stepper controller uses the same chipby Triffid_Hunter - Controllers
why do the gen3 motherboard and the extruder terminate with 180r when cat5's characteristic impedance is 100r?by Triffid_Hunter - Controllers
QuotequadshopMy board runs at 16MHz clock, which means 62.5 ns/cycle. I don't know how many cycles it takes to set a pin in AVR assembly, but if it is less than 16 cycles unlike PIC, AVR core runs at crystal frequency, so it takes just 1 clock to set or clear an outputby Triffid_Hunter - RepRap Host
sounds like ESD to me. just touching the digital inputs with fingers can destroy the chips from electrostatic discharge.. they can only withstand up to 200v discharge maybe once, but we don't feel it until about 10,000v!by Triffid_Hunter - Controllers
QuotewesjanikIs there any danger in putting enough power through cat5 wire to power the extruder board? see this threadby Triffid_Hunter - Controllers
ah, good point about the Rdson.. DRV8811 is about 30% higher ever tried cutting a hole in the board and strapping a heatsink directly to the chip's thermal pad? or mounting the chip upside down for similar purpose?by Triffid_Hunter - Controllers
looks like the DRV8811 and the A3977 TSSOP are pin-compatible with one another, which is awesome for both of us because I'm currently redesigning the v3 stepper board to accomodate the smaller and cheaper TSSOP packageby Triffid_Hunter - Controllers
if you need more ram, just add a 62256 or similar - remember, it doesn't need to be as fast as your processor, only as fast as your stepper! I wouldn't bother though, trapezoidal envelopes are trivial to calculate in real time and should work fine. has some diagrams and a heap of equations if you really want to get stuck into acceleration profile stuff, and google knows of plenty moreby Triffid_Hunter - RepRap Host
Not quite that simple, as barney noted, but certainly possible I believe.. perhaps we'll need paper templates that stick onto the faces of cuts made from other parts of the template or something. Some of mendel's parts require cuts that simply don't lend themselves to a stick-on cutting guide, and will require either a slight re-design or a multi-stage approach or possibly both. I'm going to haby Triffid_Hunter - RepRap Host
just got my motors from ausxmods, had zero issues and they arrived very quickly I was surprised to find that with the windings shorted, I was completely unable to turn the shaft, and with just one winding shorted, it was very difficult and had significant cogging. With no windings shorted, it feels like a brushless motor, a little resistance but nothing significant. This bodes well for torque Iby Triffid_Hunter - General
have never seen the "fine" pitch on anything, ever.. only standard pitchby Triffid_Hunter - Mechanics
You've skipped a carry or something, (0.1 millimeters * 200) = 10mm (circumference) which is far too close to the belt pitch to be practical - you'd need a gear with only two teeth! better off using 1/8th stepping which gives you a gear of diameter (0.1mm * 200 * 8) / pi = ~5cm and if that's too big, go for 50um precision and a 25mm diameter gear. Accuracy is usually lower than precision, ratherby Triffid_Hunter - Mechanics
re: solar melted Al, there are commercial designs for solar power stations that store energy into the night in the phase change of molten salt at 800 celsius!by Triffid_Hunter - Mechanics
I'm in the process of getting parts for a wooden mendel, would *love* to see some 2D projections of the parts online, especially if they've been altered to be easy to make from wood! Perhaps inquire about getting a section in the svn repository to upload yours?by Triffid_Hunter - General Mendel Topics
Yeah I found that bit to be rather bizarre, especially as the motherboard uses the 3.3v from the ATX to supply power to the SD card socket, and everything else has standard drive power molexes on it... I think I'll skip that part and just bolt the ATX psu on somewhereby Triffid_Hunter - Controllers
no technical reason why not that I can think of, just need different wheels to drive it, and maybe different clamps on x and y (z is continuous)by Triffid_Hunter - Mechanics
looks similar to blender's UV unwrap function mentioned elsewhere in that tutorial, could work very nicely especially for stuff with odd anglesby Triffid_Hunter - RepRap Host
pica: dunno if that would work.. toner transfer works by melting the toner, so your chopping block would probably melt too.. if you want to try anyway, glossy magazine paper is far more available and has pretty much the same effect. I'd just glue the paper on and cut through itby Triffid_Hunter - RepRap Host
from your description, sounds like internal faces of drill holes are missing or something.. open up in AoI or blender or something and have a look, they should both have some way of finding missing facesby Triffid_Hunter - Reprappers
ah there it is, didn't notice that the spreadsheet had multiple sheets :/by Triffid_Hunter - Mechanics
have been scouring the site for this tidbit of information, but can't find it anywhere. Quite a number of the assemblies in the mendel mechanical construction guide in the wiki don't mention the bearings used in the BOM. The bearing video suggests that there are 10 per axis for a total of 30, but I'd like something a bit more definite, as much as that's possible with a beta design. I'd expect itby Triffid_Hunter - Mechanics
QuoteJohnWBlimey the chip is nearly £7 from Farnell and Digikey yeah it's expensive for a chip, but consider what it would cost to do the same thing any other way and it starts to look far more attractive.by Triffid_Hunter - Mechanics
in Gen2 land, looks like every module that takes significant current has its own power molex, so there will never be significant current between them and the arduino. You do have to connect arduino ground to reprap psu ground, but a thin wire should suffice as it should only ever carry the miniscule return currents from signals. If your computer and the reprap PSU are connected to different circby Triffid_Hunter - Controllers
yeah, POE is sent at 48v too, so only 500mA per pair. QuoteStephen GeorgeSorry don't quite know what "star point is inside the PSU" as far as I know if you are connected to ground you are connected to ground that ground. (and other grounding-related comments) wire has resistance, so when current flows through it, a voltage develops across it (V=IR). Motors and heaters take significant amountsby Triffid_Hunter - Controllers