On Friday, 13 April 2018 15:23:29 UTC+1, dennis@home wrote:
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.

How often will it sample and what sort levels of spikes and transcients.
And don't forget the ADC can only really 'see' DC voltages.


Only a couple of resistors required to set the voltage range to be
within the ADC input range.

doesn't help much though, in fact depending on these spikes you might not 'see' much after reducing it through a transformer and rectifier.



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

Problem is dealing with mains AC voltages and having to reduce them first.