[Ovmsdev] OVMS CAN-USB Call for Assistance

[HONDA S-2000]

> On Sep 2, 2013, at 22:08, Mark Webb-Johnson wrote:
>>> I'll try to rough up a schematic, to see how many components this  
>>> can be brought down to. For China manufacturers, saving even 1  
>>> component brings the cost of both materials and assembly down. I  
>>> remember working with the factory to remove 1 single chip costing  
>>> US$1.10 down to a bunch of passive components costing US$0.10 -  
>>> resulting price difference was US$3 (I think they really didn't  
>>> want to use that chip, not just for the cost but also for the  
>>> hassle of obtaining it).
>> So, passives do not count as a whole component, not compared to a  
>> chip?
>
> Supposedly not. Or, at least they don't concern themselves with  
> them. I suspect that the factories have rolls of hundreds of  
> thousands of these components, ready to go. Sometimes if I specify  
> a 2.3k resistor, for example, they will come back and ask to  
> substitute with 2.2k - but that happens surprisingly rarely. Their  
> biggest concern seems to be the ICs - or maybe they are just  
> concentrating on things that cost more than a buck.


I find myself wondering whether the MCP2551 could be replaced with 2  
or 4 transistors and a handful of passives. Unfortunately, it would  
add significantly to the research effort to design a discrete  
circuit. The block diagram shows a fairly complex setup with a  
reference voltage that would probably require an IC anyway, so I  
don't there's much to gain by removing a chip if it requires another  
chip in addition to some discrete parts.

Brian