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By rikur_
FLYER Club Member  FLYER Club Member
#1839723
Has anyone got any pointers to a 'dusk until midnight' timer switch, that automatically tracks when dusk is based on the date>

At the moment I'm using a conventional timer, but every month I have to update the 'on' time.

A photocell switch isn't an option due to the location, nor is anything that requires an internet connection (it's to light a monument located in a traffic island).
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By VRB_20kt
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#1839726
Sounds ridiculously overkill, but the simplest way might be a Pi with a simple Python script and a lookup table.

Are you sure you can’t use a photocell? Perhaps with an optical pipe back to the cabinet where the switch is located?
By Cessna571
#1839732
Actually, may look like a Tapo Smart plug with a schedule set.

You can set a schedule at home, and then take it there.

It says “the schedule doesn’t need the internet to continue” so it keeps time and continues when you lose your internet.

I don’t know if it needs the internet to know when dusk is though if the schedule is set “from dusk” rather than “from time”.

Would be perfect if it doesn’t.
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By rikur_
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#1839764
VRB_20kt wrote:Are you sure you can’t use a photocell? Perhaps with an optical pipe back to the cabinet where the switch is located?

A couple of reasons why I'm keen to avoid this:
1) The controls & supply are all in a weather tight steel cabinet. It keeps the safety case easier to have no 240v outside the cabinet (the lights are all 12v)
2) The area is illuminated with streetlights and passing headlights. We tried a 12v photocell switch, and it kept toggling spuriously.

Colonel Panic wrote:Sangamo do solar time clocks - and they are dumb / no need for www.

That's the sort of thing I was looking for. Ideally without the £150 price tag, but that's not necessarily a show stopper if that's what it needs to be.
Cessna571 wrote:Actually, may look like a Tapo Smart plug with a schedule set.
You can set a schedule at home, and then take it there.

I did ponder something like this - the difficulty was working out whether they e.g. use an internet connection to initialise their time or fetch periodic updates to sunset times. I actually have an old X10 controller which will control an X10 switch exactly as required. However, it has to be configured via a WinXP laptop and a serial lead, each time the two x AA batteries go flat. Doesn't feel like something I could fairly handover to someone else!
#1839767
rikur_ wrote:That's the sort of thing I was looking for. Ideally without the £150 price tag, but that's not necessarily a show stopper if that's what it needs to be.

There are loads on eBay for much less - just search on Sangamo, and make sure you get the correct model.
rikur_, Flyin'Dutch' liked this
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By stevelup
FLYER Club Member  FLYER Club Member
#1839818
The Steinel thing is excellent - this one:-

https://www.steinel.de/en/lights-sensor ... 50516.html

You can buy it here:-

https://www.tlc-direct.co.uk/Products/STNM3000B.html

But it does not feature any kind of fixed time clock - so won't turn off at exactly midnight. What it does is come on at dusk, then go off a certain number of hours later (which you can adjust). It then comes back on just before sunrise and goes off again at sunrise. It's all automatic and learns the changing lengths of the day throughout the year. Passing headlights and street lights do not fool it.

Highly recommended.
Flyin'Dutch' liked this
#1839829
But that Steinel unit requires a lux input - something that the OP said wasn't possible.

The Sangamo units can be programmed to come on at dusk (+/- mins IIRC) and go off at a fixed time (eg 23:59). You set the latitude & DD/MM once, and from then on it knows when dusk is.

NB: The round mechanical units do NOT just for GMT / BST, but the digital DIN rail units might.
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By Flyin'Dutch'
FLYER Club Member  FLYER Club Member
#1839849
In keeping with the mantra, when in Rome do as the Romans we have these blinds on the windows and until a few years ago they were controlled by a bog standard clock.

I got pretty quickly fed up with that as especially in spring and autumn you have do change them every week or so to achieve something resembling sensible times. Replaced them with units which work out SS/SR after you have adjusted time and lattitude once and job done forever.

Would have thought something was available for some light as well.
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By rikur_
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#1839854
stevelup wrote:It’s only not possible because of the artificial requirement not to penetrate the box. The 240V must get into there in the first place. It’s just a second hole!


There are two ducts to the cabinet.
The 240v comes in on armoured cable in one duct from the adjacent lamp post. The other duct takes the 12v cables to the lighting. The cabinet is set in concrete, with the ducting surfacing through the concrete in the base of the cabinet. The 12v ducting is not suitable for mains cabling (it's ducting in a public highway, so specific standards apply), and the safety case for the installation was on the basis of not having 240v outside the cabinet. Further there's not really anywhere suitable to mount a photocell. The cabinet is low level next to the pavement/crossing, the monument being illuminated is listed so can't easily fix anything to it.

So whilst we probably could dig up the pavement to get an additional duct in, put in a pole to mount a photocell, and get someone out to signoff a revised safety case - it's probably just easier to replace the existing timer, with something like what @Colonel Panic suggested.

Just need one to come up on ebay from Zone 3.
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By rikur_
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#1839860
stevelup wrote:Can’t the photocell be fitted to the lamppost?

Possibly, with some sort of wayleave agreement with the highways authority that owns the lamp post. Technically I could even drop a line down the post from the existing photocell on the light.

To put it in perspective, we could have technically run all the electrics from the junction box in the base of the lamp post, but it was easier procedurally to install a new cabinet 2ft away as it was too difficult to get agreement to put one authority's equipment in another authority's lamp post. It was explained to me 'we can get two lads to dig a trench for a new cabinet in a couple of hours, or you can get two lawyers to draft a wayleave agreement over a couple of weeks, I can tell you which will be cheaper'.