Re: New project...PCI based servo control board

[Robin Szemeti <robin-at-redpoint.org.uk>]

On Thursday 27 March 2003 07:37, Malte Rütemann wrote:
> Hi,
> I've a simple but i think good idea:
> Jon why dont you sell the FPGA alone?
> I think most people want to build the interface at home, to save a lot of
> money, and if they could get the FPGA for around 100-200$,more people would
> buy it. So if you only sell the FPGA, and perhaps the PCB, you could "make
> more" money, and we(??), would all be happy, and nobody wants to invent it
> new.
> And perhaps, when you have sold enough, you can make the wohle GPL, because
> I think the most people are not able  to burn the FPGA, so you could still
> sell them.
> Its only an idea, but it is the way to earn enough money for buying the
> daily bread.

Well ... look at it from Jon's poin tof view ... he did all the work and at 
$200 its a fair price (I'd say a cheap price)  ... he builds and tests the 
boards, sends them out ... job done ... as soon as you start selling them in 
kit form, for less money, he loses out on the assembly time (which is 
included in the $200) .. so has to sell even more to get his investment back 
(it doesnt sound like he's sold that many that he's up night and day 
assembling them ... lets assume that at the moment, hes got time to do this 
task) ... and .. then he'll get all those questions from people who have 
problems ... 'hey ... I just assembled htis board and I can't get it to work 
...' and thats more hassle for no money .. (go on, just how many people do 
you think will solder in a surface mount FPGA right first time ?)  I htink 
Jon's approach of selling only pre-built units is the right one for now at 
least.

Sure .. one option would be an 'open source'  project, with just some FPGA 
code, a postscript file of the board and some instructions ... the other 
route is someone burns the FPGA, sources the boards, but then it up to them 
how htey sell it ... when someones putting in the investment to do that, I 
reckon they are entitled to a little profit.

FWIW, I prefer an 'outboard' solution rather than PCI.  Couple of reasons, 
the breakout from a board in a computer to means another interface board and 
connectors ... and what about solid state relays? ... mounted on the PCI 
card? machine voltages inside the computer case? .. will the breakout 
connector take the current? ...  and then theres positioning ... the best 
policy is to keep the leads from the encoders as short as possible ... that 
means mounting the interface as near to the motors as possible, in some 
situations that may be some way from the controller PC .. (think big router 
tables) ... IMHO, the computer is best viewed as 'the controller' and any 
interface units are best done outboard and connected to the controller using 
one of the many interfaces (serial/printer/firewire/ethernet .. shall I go 
on?) that are available ...

Still, I'll watch with interest if you get it going .... 


-- 
Robin Szemeti

Redpoint Consulting Limited
Real Solutions For A Virtual World