If what you want is horsepower, take a look at the STM32F4 (168MHz/210DMIPS) and the LPC43xx series (204MHz/255DMIPS), both have SIMD and DSP extensions Each of these processors has so many built-in peripherals that there aren't enough pins in a 100-pin package for all of them, including ethernet and USB, and 512kB-1MB of flash. and at least 136kB of RAM The LPC43xx runs in big/little mode--thaby Annirak - Controllers
Quoteledvinap This is true, but it should not be big problem. You only need to know some approximation of current position (just knowing that current configuration is in working space is enough with some robot configurations) and then you can at least plan homing movements. I don't know the math required to work out a homing algorithm that will work for all starting points within the coordinateby Annirak - Delta Machines
Polygonhell Wrote: ------------------------------------------------------- > Actually the 6 arm bot isn't over constrained, > unless you artificially constrain the platform to > be horizontal, and not to rotate. > It has 6 DOF XYZ and some degree of roll pitch > yaw. Maybe overconstrained is the wrong word. I'm not trying to say that both don't have the same number of degrees ofby Annirak - Delta Machines
ledvinap Wrote: ------------------------------------------------------- > In fact calibration of 6-dof robot is quite easy. > Just take some measurements and solve machine > dimensions as optimalization problem - you dont > even need to understand the problem, just use > snandard solvers for bunch of points. The point is not initial calibration, it's that you have a multiply constby Annirak - Delta Machines
NewPerfection Wrote: ------------------------------------------------------- > > Oh, I know that stuff exists. Most people don't > have thermal adhesive, but more likely have both > epoxy and thermal compound. I'm a cheapskate That's fair, but the stuff isn't exactly expensive: about $13. My criterion for this is that if enough thermal adhesive to mount all your stepper driversby Annirak - Controllers
NewPerfection Wrote: ------------------------------------------------------- > I've used superglue, it works quite well. It may > even transfer heat better than the foam stickies > since the interface is so thin. You could also > mix up some epoxy with heatsink compound, about a > 50-50 ratio. You're doing it wrong ;-)by Annirak - Controllers
I think the calibration would be the hardest part. Homing with a 6-actuator head is non-trivial. In fact with any more than three actuators, it's non-trivial.by Annirak - Delta Machines
Have you guys seen Lego's linear actuators? The design behind them is essentially R&P, but done as a worm drive instead. A single unit does linear bearing and linear actuator. Lego actuators themselves wouldn't work for this, but the design might work. I don't know if it's covered by patents or not.by Annirak - Delta Machines
@ Mofosyne: Absolutely, four arms is possible. The math is, in fact, the same. The only problem is that with an additional degree of freedom, the movements of the arms must be more coordinated to prevent binding, which makes calibration far more important, though you do end up with a more stable and more accurate platform. @Darhuuk: There are several tradeoffs involved. You want to have the shby Annirak - Delta Machines
You might need to use telescopic arms, like this one doesby Annirak - Delta Machines
The build area is essentially a Venn diagram of the maximum reach of each arm. The central, intersecting set is the build area. If the reach of an arm is less than the pillar-to-pillar spacing, then there are cutouts in the set where the arms cannot reach. You can see that as the reach of the arms increases, the build area becomes a triangle. As the reach of the arms decreases, the build arby Annirak - Delta Machines
@TonyD I'll be working on that this week; I'll post here either with updates or a link to a more suitable thread.by Annirak - Controllers
Unfortunately, bobc is approximately correct. The gertboard does not bring out enough high-power I/O to make it useful as a single-board expansion for the raspberry pi. You would need to build another board for the stepper motor controllers and the hot-end controller. You'd be better off doing a dedicated board to expand off of the Raspberry Pi.by Annirak - Next Wave Electronics Working Group
I looked at those but I could never find one which was actually in stock. The Stellaris (Luminary) ones seemed better--Cortex M3 vs M0 for the NXP ones--but the ones I could find are SOIC, not DIP.by Annirak - Controllers
My solution shouldn't require any additional controllers; just the RPi since I'm using SPI-based, fully integrated stepper motor motion controllers. R2C2 looks pretty nice. My only complaint about it is the lack of modular expansion of stepper drivers. I'm constantly debating that tradeoff, but I think there's some significant benefits to be had by going with the RPi.by Annirak - Controllers
DeuxVis Wrote: ------------------------------------------------------- > USB communication doesn't seem fast enough for a > lot of little moves following each other - like in > a tiny circles drawn using way too small lines. > > People had noticeable improvement in print quality > using Sd card on the controller, instead of USB > communication from the host - removes the shoby Annirak - Controllers
sam0737 Wrote: ------------------------------------------------------- > And there is a big "but" if the position > computation is moved to the host - you lose the > print by SD function! Or you need a host on the > printer Raspberry Pi? The printer raspberry pi has a pair of USB ports. Why do you need print from SD? You have print from USB.by Annirak - Controllers
With two spare GPIO, you can have enable-in and enable-out, which allows you to set up each device without jumpers, based on its position in the chain.by Annirak - Controllers
pete-theobald Wrote: ------------------------------------------------------- > * Some way to set the nodes address. I was > planning to use a dip switch but i've run out of > pins. I could program it directly into eeprom but > that needs the user to have a pic programmer which > is another £25 If you have a spare ADC pin, you could make something like a R2R DAC with the DIP switchby Annirak - Controllers
If you can keep the PCB size to 50mmx50mm or smaller, iteadstudio will manufacture 10 of them for $9.90.by Annirak - Controllers
Hi Pete, I don't want to completely hijack your thread with my design work, so I'll try to be brief. pete-theobald Wrote: ------------------------------------------------------- > Hi Annirak, > > SPI would seem practical but I'm not sure the data > rate would be up to it. If we assume we have 5 > motors, and we want a max speed of 160mm/s. With a > 16 tooth t2.5 pulley we'd haby Annirak - Controllers
annodomini2 Wrote: ------------------------------------------------------- > But is the PIC32 supported as a result? And if so, > how well is it supported? AFAIK, that's the benefit of using a standardized core. The core itself is well supported (MIPS32 M4K). I can't speak to the support of the peripherals, but that's something that's not too bad to overcome. A quick google brought up tby Annirak - Controllers
As for using the PIC32 as an option, it seems like the only DIP or PLCC package MCU with hardware DIV support. Since DIV is a bottleneck for path planning, and MIPS32 is a gcc-supported architecture, that seems like a sensible solution. Personally, I'm not going to spend any effort on that--either I'll build something with L6470's for my own interest, or I'll buy a R2C2 build. Upon some reflecby Annirak - Controllers
I'm still doing some work towards a RPi solution with the L6470. I know it's not very DIY friendly, but I've concluded that Gen7T is about as DIY friendly as we need to be. No sense in me reinventing that. Instead, I'm trying to work a design so that I can take all the stepper management and timing out of the system and remove the MCU entirely. I don't know if that counts as one-sided. Maybeby Annirak - Controllers
bobc Wrote: ------------------------------------------------------- > The L6470 look like clever devices, do you have an > idea of cost of a system vs typical arduino/pololu > system? The bare chip costs $9.23 in 10 unit quantities. It is small enough to fit two on a 5cm x 5cm board, so the PCB cost is $0.50/axis. Add about $2.50 per axis in connectors, discretes, and passives. Totalby Annirak - Controllers
PIC32 is MIPS32, which has gcc support.by Annirak - Controllers
I'm working on a variant of this approach: I'm going to use L6470 stepper drivers, which are massively integrated drivers: you give them target position, velocity, acceleration, and deceleration arguments, and they do the rest. I'll control these with a Raspberry Pi. I'm about 50% done the design work; I'll let you know how it goes.by Annirak - Controllers
Is 63C sufficient for heated bed applications?by Annirak - Controllers
After looking at R2C2, smoothieboard, and 4pi, there doesn't seem to be much sense in my continuing down this avenue. Several other people have already done essentially what I intended to do.by Annirak - Next Wave Electronics Working Group