On Fri, 28 May 2021 14:31:22 +0100, Robin wrote:

On 27/05/2021 23:27, T i m wrote:

snip


I'm not trying to actually 'measure' anything (although the sorts of
levels are interesting if they are correct and when compared with the
stated light output levels of domestic lighting) but to just get the
comparable levels that could be useful to automate what might equal
'it's a bit dark outside, better turn the light on', or enable the
'turning on a light on in the hall automatically with a PIR during an
overcast day and before sunset' ... sort of thing. ;-)


For that purpose I think you can safely forget about losses from
anything that starts off looking clear and is stable.

The bit of very clear blister pack seemed to have quite an impact so
I'll run some tests and compare. ;-)

The odd 20% is
neither here nor there.

True, if I'm only interested in the difference in levels etc.

The difference in illuminance between direct
sunlight and an overcast day is around a factor 100.

Yeah, So I've already observed, or even a cloud going over.

https://ibb.co/QHfKhv9

It's another
factor 10 or so down to a typical living room at night.

Noted.

JOOI does the home automation software have built-in facility to ignore
short-term changes so e.g. the headlights of a car arriving don't turn
off the lights on the stairs?

Hehe ... erm, I'll say 'yes' in as much as you can set thresholds and
delays plus conditions where once triggered (because it was much
darker than usual say 1hr before sunset) then it would trigger the
lights on but wouldn't allow the lights to be turned back off till say
midnight or sunrise etc.

Within each Automation you can have multiple triggers, multiple
conditions and multiple actions (turning on several lights at specific
brightness etc).

Cheers, T i m