Raspberry Pi

[Robin Hewitt]

Sadly my knowledge of Linux is insufficient to do such a port myself. I was thinking more of a stand-alone solution along the lines of FASM or DEX-OS...

Hi Irving

And very nice to have you back, Sir. I think the Raspberry could be a bit of a red herring, I think you really need an ARM processor on a board with a crystal, USB socket, IO pins and the six pin header that puts in the USB loader so you can program it live.

The problem is getting started, but once past the "Hello World" stage you should be on a roll. The processors start at a couple of quid, if you stay below 60MHz they are dirt cheap. If you fancy a collaboration I am your man.

Robin

[Jonathan]

If you fancy a collaboration I am your man.

Me too. If there's one that's available in a sensible package, i.e. not much smaller pin spacing than SOIC then I'm up for making us some 'development boards' as you suggest. Unless of course there's something cheap and suitable already available.

[bobc]

There are many cheap ARM eval boards around, I set a goal to find the cheapest! The cheapest so far I have found is the STM32 discovery http://uk.rs-online.com/web/p/proces...-kits/7458434/ for £10. No wait, here is a cheaper one! http://uk.rs-online.com/web/p/proces...-kits/7587554/

I've got one of the former, haven't done anything with it yet. Instead I build one of the LPC1343 boards you can here http://code.google.com/p/micropendou.../Older_Designs. The nice thing about the LPC chips is they come with a USB bootloader built in, it loads likes a USB flash drive. You just need the GNU compiler and you can start using it.

I have been using it to make a Control Panel for a 3d printer, you can just make out the board here http://www.flickr.com/photos/4829929...in/photostream

There are some many options now, we are spoilt for choice. The only thing is if you are into DIY hardware, there are virtually no ARM chips in a DIP package, all LQFP or smaller. The '1343 board above is not too hard to build, I used the two soldering iron technique, a magnifier, and patience ;)

I have some spare blank PCB's if anyone wants one, most of the parts are available via RS or Farnell.

ETA; design files and sample firmware for my project is at https://github.com/bobc/bobc_hardware

[Robin Hewitt]

I have been using it to make a Control Panel for a 3d printer,

Blimey! I thought all the "interesting" people on the planet lived miles away from me, but here you are just up the road

[bobc]

Blimey! I thought all the "interesting" people on the planet lived miles away from me, but here you are just up the road

Heh, I didn't expect to find a "high-tech" client in Eastbourne, for some reason they have a factory and design centre here. Normally I am found cruising up and down M25/M4. It's a gentler pace of life down here, shall we say ;)

[irving2008]

Maybe the Pi isn't the way to go, but my thought process was to create a g-code interpreter to drive the stepper drivers etc. and provide a real-time display of the process. Sort of MACH3 in a matchbox... (or should that be EMC2 in a matchbox)... anyway, a cut down version. No frills, no bells n whistles, just motion control and some graphics. I don't think the other boards suggested can do this (well of course with a multitude of added perpherals maybe). Big ask? maybe.

I/O isnt an issue, already sketched some ideas for a 16 port TTL compatible I/O module that uses a minimal # of GPIO and will be fast enough for this purpose (a few uS switching time and some bit-banging software) with an RTC as well. Also looking at using the I2C interface for the same, albeit slower...

So far just knocked up a simple I/O connector to get to the breadboard easily.

[bobc]

Maybe the Pi isn't the way to go, but my thought process was to create a g-code interpreter to drive the stepper drivers etc. and provide a real-time display of the process. Sort of MACH3 in a matchbox... (or should that be EMC2 in a matchbox)... anyway, a cut down version. No frills, no bells n whistles, just motion control and some graphics. I don't think the other boards suggested can do this (well of course with a multitude of added perpherals maybe). Big ask? maybe.

It is entirely possible, it is what all the Reprap printer controllers do, they take GCode sent from a PC over RS232, plan the motion and control the steppers, and on the 8 bit Arduino platform. There is also software for CNC, have a look for GRBL.

It is the sort of project you can do from scratch, you may not achieve reliable motion control on the first go, but steppers are quite easy to work with. If you have got a Pi, you may as well use it. The nice thing about the Pi is you can use a nice sized display with it.

My Pi should arrive any day now!