On 13/04/2018 10:24, newshound wrote:
On 13/04/2018 07:48, Halmyre wrote:
On Thursday, April 12, 2018 at 1:59:45 PM UTC+1, newshound wrote:
On 12/04/2018 12:51, The Nomad wrote:
On Thu, 12 Apr 2018 12:37:06 +0100, newshound
wrote:

For reasons I won't bore you with, I'm interested in building a cheap,
simple data logger to monitor mains voltage, ideally two channels
(live
to earth and neutral to earth). In the dim and distant past I have
designed and built such things more or less from scratch, but surely
someone has already done this.

I havn't used either Arduino or Pi before, but I assume one or other
would be the obvious starting point.

However ATM google isn't giving me a strong lead. Thoughts?

A quick google came up with:

https://openenergymonitor.org/forum-archive/node/58.html

https://circuitdigest.com/microcontroller-projects/arduino-ac-voltmeter


https://www.briandorey.com/post/ardu...e-and-current-
logging

Avpx

Thanks, that second one looks like a good basis.

Won't the capacitor smooth out any transients you might want to observe?

I am looking for transients longer than maybe a second or so. Obviously,
might need to experiment with capacitors a bit.

You need a simple mains transformer to a few volts and feed it into the
A-D converter on an arduino and do some maths on the samples.
Only a couple of resistors required to set the voltage range to be
within the ADC input range.

A nodeMCU will almost certainly do everything you want including logging
to a remote database.