Time for a purpose built motion control computer.

[ecat]

Ok, let's run with this:

I have a little chip sitting right beside me, 80MHz clock, 1/2MB flash, 32k RAM and something like 80 I/O pins, it costs about £5.

It's a surface mount component so add £15 for a board we can work with.

We need some way of getting data to it, say £5 for USB and/or £15 for Ethernet.

A keyboard of some sort, either discrete buttons, say 50pence each, or we could possibly use a USB key pad of some description.

Display options, the possibilities are vast. Off the shelf graphical LCDs are expensive and can be tricky to interface, say £50 for a 3 inch screen - have a look around for options. Or maybe just a set of old fashioned 7 segment units, say £1 each including glue logic.

Case, say £10 to £20.

Assorted connectors £20 <shrug> always more then you think.

Power supply for logic, a wall-wart is the safe option, £10.

The above is guess work but pretty much reflect UK prices.

These are your basic hardware building blocks. We now need a full hardware design and complimentary software design, as I still know feck all about CNC I'll leave these open for discussion :)

[Robin Hewitt]

I have a little chip sitting right beside me, 80MHz clock, 1/2MB flash, 32k RAM and something like 80 I/O pins, it costs about £5.

I have a little chip, 40MHz, 64 pins, £1.88 at 1000 off, already soldered to a PCB.

On the back 4 RJ45 sockets for 3 stepper drivers and 1 phase converter, 3 switched outputs, 6 buffered inputs, 1 USB socket and one header plug to connect one of those big fat positioning knobs. On the front an RJ45 for the pendant, a spindle speed knob, 5 push buttons and one concealed RST button.

I built if for my machine so it has everything I want. Would work for anyone who built their machine around it, but people build their machine then think about how to control it. Cart before the horse perhaps, but that's exactly what I did :naughty:

[GeoffV]

Robin

Thank you for your contribution, you clearly have much valuable experience in these matters.

Geoff Vaizey

[GeoffV]

Dear ecat

Thank you for your previous contribution with the link to slides and ballscrews, but most of all thank you for getting the ball rolling.

I have to start by saying much of the above sailed clean over my head, but if your initial cost estimates are realistic you have confirmed my suspitions that a suitable controller need not cost a fortune. I wish I could contribute technically but I can't, however I can help with organising such a project and would be prepared to fund a prototype or two to prove the system, after which those in the team could progress however they wish.

Perhaps when you have a moment you could list the other difficult areas so that members with relevant experience may be enthused enough to join in.

Geoff Vaizey