Field Mills (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 07 Jul 2004 21:16:34 +0930
From: Matthew Smith <matt@xxxxxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Field Mills

Hi All

I've had another look at the Scientific American field mill schematic.  I've got
samples of appropriate opamps ordered from National and TI.  Being a digital
guy, I'm going to feed the output into an Atmel AT90S8515 or AT90S8535
microcontroller so that I can get RS232 out.

I'll probably do this as two boards, so that I've got a universal analogue to
RS232 module which I can pop onto other front ends.  I still fancy the idea of a
digital "grid dip" meter for finding the resonant frequency of Tesla coils, and
this module could be part of it.

The field mill board will be pretty much as described in the article, with part
substitution at the front end.  (The part specified is equivalent to an old
Burr-Brown chip; I'm using a more modern replacement.)  I'm looking at replacing
the range resistors with something that can be controlled electronically (by the
microcontroller).

Software wise, commands to the microcontroller could be:
* motor on/off
* range select
* select sample period

My idea is that, once running, the uC will send a value up the wire every
second, or whatever interval you choose.

Cheers

M

-- 
Matthew Smith
Kadina Business Consultancy
South Australia