[chbot] SMD experiment #1

[Chris Hellyar]

> Nice project.  It sounds successful, despite the lack of polish.

:-).  I have no idea what you mean, this is a very polished, and
professional process...

I'm in another hold-loop now waiting for the MAX6675's to turn up
from the US, the MOQ and pricing from the NZ agent was a little 
nuts for the scale of this project.

FYI, if you're looking at doing thermocouple voltage sensing in 
the range 0 to 700c the Max6675 is cool, thermocouple in one side,
SPI interface out the other.  12bit result.  Gives 0.25c steps and
3c accuracy which is more than enough for many things.

Down sides are that is doesn't do negative temps, and it only comes
in an SMD package.

ref: 
http://datasheets.maxim-ic.com/en/ds/MAX6675.pdf

Cheers, Me.