Car Park Movement switching or sensor options

Actually you need to think out of the box. Lights off all the time, then on if a car enters, or a person enters through the door., perhaps on for 5 minutes then off again. Notices pointing out this operation. Override with receptionist if car breaks down or similar whilst it is fixed. Parked cars do not need light! You could probably save £20k per year or more, for the cost of a few remote type PIRs, and fixing the contactors if broken! Car park still lit while anyone there for potential personal safety issues. You might need a relay controller to get the logic right and programmable.

I normally charge a lot for this kind of advice!

How safe is this against vandals, and generally how are the environmental conditions, ? Electronic sensors vary in their IP rating.

As noted 'mostly off' can be the default state, perhaps enough to maintain an emergancy exit level but it does mean some extra cores in the wiring, so that cost needs to be offset against the saving.

Some hard sums about what it costs to run need to be done first and how much labour that will pay for.

Depending how the LED fittings are made it may or may not be possible to add a sensor into each lamp but it is not the way I would, as it makes it hard for someone following  to maintain also - you do not want really the consumption of too many  of sensors at 5W each, to switch  LEDs at 20W each.

The central contactor or one per large zone is a nice idea, and coupled with a timer of perhaps 15 mins and a number of sensors  in key places that trigger it .

Mike.

Why 15 minutes Mike, it is only 100m in size or so? If access is unlimited then every entry is potentially a problem and CCTV of the entrances is the answer, not more power consumption on the lighting. And 5W per PIR is ridiculous. This needs a proper Engineering answer not a "What if" kind of view, it is just too expensive.

To allow folk to get to their cars, put their bags in, start the car, manouvre round other cars and drive out without sudden change in light level causing an accident.  And to avoid excessive switching at peak times.

M.

How  much current do you think a PIR sensor draws ? On and off states both need to be considered It will be less in the off state.

Do we need to address switching times to reduce switching operation numbers? Are LEDs along with filament lamps and fluorescent lamps  life expectancy de-rated by numerous energising/de-energising cycles?

They shouldn't be affected. There is no known mechanism provided that the power supply can cope and not overload the LEDs during switching. LEDs running on Unsmoothed rectified mains for example are switched on and off at 50Hz.

Thanks for that clarification David

Are there any access controls? For example if there is a shutter or barrier that has to open to allow a vehicle to enter, this could trigger a timed activation of the lights. If there are any pedestrian entry doors these too could act as a trigger.

If you are concerned about motion you could add some motion detectors operating on the basis that a bit of logic means an entrance must have been triggered first if there are concerns of spurious triggers from foxes or similar. This will ensure that if someone has entered the carpark the lights stay on until they've left and might be a bit more accurate than purely relying on motion detection.

A simple approach could be time lag switches on entrances.

If there is CCTV in place you may be able to take a trigger out of that on detection of movement, or virtual trip wires etc.

Key will be to lay out the requirements and prioritise the most important to the least important and that should guide towards a solution(s) which can be costed.

Thank you all for the responses to this post.

Kind Regards

Tatty

Very interested in this thread. I am currently putting together a project proposal to have sensor-controlled lighting for our external areas. I am an electrical supervisor for a civil engineering company which operates 24/7. We are trying to be more eco-friendly and one of the areas i am looking at is the depot lighting which is currently on all night. i have split the site down to 3 areas with a total of 30 led floodlights (already existing) and i am looking to install a mix of Master motion sensors and slave sensors. Obviously, the masters trigger all lights within a zone whereas the slaves are independent of and work in conjunction with, the master sensors. I am currently in discussion with a well-known lighting company. I will let you know how that works out. in the meantime, if you find a suitable solution i would love to hear about it!