Another data logger?

[Andrew Skinner]

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Every good electronics engineer feels impelled and excited at the concept of
designing a new data logger, and its easy to convince yourself that you have
a special reason for doing so. 

This is a temptation I have had to resist myself for the 17 year lifetime of
this small company dedicated to data logging applications (and with a real
track record in building hundreds of data logging systems based on Unidata
loggers, DataTaker loggers, TinyTalk and Hobo loggers etc)

There are two reasons to resist: -
1) The 50% rule

A new product entering an existing market must obey the 50% rule.  It must
either be 

*	50% better and the same price,
*	20% better and 30% cheaper
*	30% cheaper and 20% better
*	50% cheaper and the same quality.

Can you do this?

2) Here's the real clincher! The cost of a data logger is not in the
electronics, although that's the "brick" you buy. 

The real development money is in the software. Firstly in the logger
"firmware", which is the software that makes the logger work when it is
discinnected from the "mother" computer. Lets call this 20% of the cost. 

Then there is the PC-based software which is the "window" through which your
customer will view his application, generate graphs and plots and tables,
view real-time information, export files, load and unload the data logger,
generate new applications and so on.

Big bucks, this...the other 80% of the cost. 

In fact, if the manufacturer of the logger you buy isn't up to providing
good software, and some aren't, then you have to write your own, as we have
done (MEA's "Magpie" software). Allow at least two man years as the most
optimistic forecast for you expensive software engineers to get this done.

So avoid that temptation unless there is no other possibility, or unless you
already have an existing product or product range that you can build up
from.


Andrew

Andrew Skinner FIICA  FIEAust CPEng
Engineering Director
Measurement Engineering Australia
41 Vine Street
MAGILL  SA  5072
Ph 08 8332 9044  Fax  08 8332 9577
Andrew.Skinner@mea.com.au
www.mea.com.au