Lights with low heat output
 

Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

Lights with low heat output
 

Lights with low heat output
 

On 19 Nov 2006 14:33:10 -0800, wrote:

Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

LEDs do not run cool. No form of lighting runs cool. HTH.

Lights with low heat output
 

In article .com,
writes:
Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

There are low voltage fluorescents.
You haven't given enough info for any detailed reply.
LEDs you are likely to find used in most lighting are
similar efficiency to filament lamps.

--
Andrew Gabriel

Lights with low heat output
 

Steve Firth wrote:
On 19 Nov 2006 14:33:10 -0800, wrote:

Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

LEDs do not run cool. No form of lighting runs cool. HTH.

Low pressure sodium comes damn close - IIRC 80% efficient.
'normal' fluorescents are around 50%.

Not to mention that at low enough powers, most forms of lighting won't
heat up much.

Lights with low heat output
 

On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
wrote:

|On 19 Nov 2006 14:33:10 -0800, wrote:
|
| Are there any commercialy-available low voltage lights which run cool?
| Anything other than LEDs?
|
|LEDs do not run cool. No form of lighting runs cool. HTH.

Depends what you mean by cool.
LEDs do not run *cold*, (at ambient temperature) but run at a low lower
temperature than incandescents, halogens etc, which in my book classes as
*cool*
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Lights with low heat output
 

Dave Fawthrop wrote:
On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
wrote:

|On 19 Nov 2006 14:33:10 -0800, wrote:
|
| Are there any commercialy-available low voltage lights which run cool?
| Anything other than LEDs?
|
|LEDs do not run cool. No form of lighting runs cool. HTH.

Depends what you mean by cool.
LEDs do not run *cold*, (at ambient temperature) but run at a low lower
temperature than incandescents, halogens etc, which in my book classes as
*cool*

They generally produce the same amount of heat for a given amount of
light - it's just spread out more.
And the LED junctions themselves have to remain at a moderately low
temperature (50C) to have a reasonable life in most cases.

Lights with low heat output
 

On 20 Nov 2006 10:13:16 GMT, Ian Stirling wrote:

|Dave Fawthrop wrote:
| On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
| wrote:
|
| |On 19 Nov 2006 14:33:10 -0800, wrote:
| |
| | Are there any commercialy-available low voltage lights which run cool?
| | Anything other than LEDs?
| |
| |LEDs do not run cool. No form of lighting runs cool. HTH.
|
| Depends what you mean by cool.
| LEDs do not run *cold*, (at ambient temperature) but run at a low lower
| temperature than incandescents, halogens etc, which in my book classes as
| *cool*
|
|They generally produce the same amount of heat for a given amount of
|light - it's just spread out more.

Just not true :-(
Almost all the power used by a 100W incandescent bulb goes into the room as
heat, only a tiny amount as light. Everyone who has burned a hand on a
lit light bulb will know that. A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Lights with low heat output
 

Dave Fawthrop wrote:
On 20 Nov 2006 10:13:16 GMT, Ian Stirling wrote:

|Dave Fawthrop wrote:
| On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
| wrote:
|
| |On 19 Nov 2006 14:33:10 -0800, wrote:
| |
| | Are there any commercialy-available low voltage lights which run cool?
| | Anything other than LEDs?
| |
| |LEDs do not run cool. No form of lighting runs cool. HTH.
|
| Depends what you mean by cool.
| LEDs do not run *cold*, (at ambient temperature) but run at a low lower
| temperature than incandescents, halogens etc, which in my book classes as
| *cool*
|
|They generally produce the same amount of heat for a given amount of
|light - it's just spread out more.

Just not true :-(
Almost all the power used by a 100W incandescent bulb goes into the room as
heat, only a tiny amount as light. Everyone who has burned a hand on a
lit light bulb will know that. A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

You specifically mentioned LEDs, and my response was clearly about LEDs.
And the tubes of most CFLs hit 100C.

Lights with low heat output
 

I want to light an alcove by mounting a "strip light" of some sorts on
a nearby beam. But the beam is only 4 feet above the floor so I want to
install a light which has less risk of burning or shocking the kids if
they accidentally break it.

Lights with low heat output
 

Andrew Gabriel wrote:
In article .com,
writes:
Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

There are low voltage fluorescents.
You haven't given enough info for any detailed reply.
LEDs you are likely to find used in most lighting are
similar efficiency to filament lamps.

Actually they are about ten times as efficient..

Lights with low heat output
 

Ian Stirling wrote:
Steve Firth wrote:
On 19 Nov 2006 14:33:10 -0800, wrote:

Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?
LEDs do not run cool. No form of lighting runs cool. HTH.

Low pressure sodium comes damn close - IIRC 80% efficient.
'normal' fluorescents are around 50%.

about 20% IIRC. LED about 10%. Incandescent about 1%.


Not to mention that at low enough powers, most forms of lighting won't
heat up much.

Lights with low heat output
 

Ian Stirling wrote:
Dave Fawthrop wrote:
On 20 Nov 2006 10:13:16 GMT, Ian Stirling wrote:

|Dave Fawthrop wrote:
| On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
| wrote:
|
| |On 19 Nov 2006 14:33:10 -0800, wrote:
| |
| | Are there any commercialy-available low voltage lights which run cool?
| | Anything other than LEDs?
| |
| |LEDs do not run cool. No form of lighting runs cool. HTH.
|
| Depends what you mean by cool.
| LEDs do not run *cold*, (at ambient temperature) but run at a low lower
| temperature than incandescents, halogens etc, which in my book classes as
| *cool*
|
|They generally produce the same amount of heat for a given amount of
|light - it's just spread out more.

Just not true :-(
Almost all the power used by a 100W incandescent bulb goes into the room as
heat, only a tiny amount as light. Everyone who has burned a hand on a
lit light bulb will know that. A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

You specifically mentioned LEDs, and my response was clearly about LEDs.
And the tubes of most CFLs hit 100C.

LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Lights with low heat output
 

Lights with low heat output
 

Ian Stirling wrote:
There are many, many enclosed strip-lights.
It may be appropriate to paint the bit next to the beam brilliant white,
and mount it on the side of the beam.

Yes, Ian, I had the same thought about mounting. With regards to a low
volt + low heat strip light though, which would you suggest I take a
look at?. There seem to be a few LED strips and that's all.

Lights with low heat output
 

The Natural Philosopher wrote:

Ian Stirling wrote:
Dave Fawthrop wrote:
On 20 Nov 2006 10:13:16 GMT, Ian Stirling wrote:

|Dave Fawthrop wrote:
| On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
| wrote:
|
| |On 19 Nov 2006 14:33:10 -0800, wrote:
| |
| | Are there any commercialy-available low voltage lights which run cool?
| | Anything other than LEDs?
| |
| |LEDs do not run cool. No form of lighting runs cool. HTH.
|
| Depends what you mean by cool.
| LEDs do not run *cold*, (at ambient temperature) but run at a low lower
| temperature than incandescents, halogens etc, which in my book classes as
| *cool*
|
|They generally produce the same amount of heat for a given amount of
|light - it's just spread out more.

Just not true :-(
Almost all the power used by a 100W incandescent bulb goes into the room as
heat, only a tiny amount as light. Everyone who has burned a hand on a
lit light bulb will know that. A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

You specifically mentioned LEDs, and my response was clearly about LEDs.
And the tubes of most CFLs hit 100C.

LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Hi

Surely the primary reason for using them in traffic lights is to reduce
ongoing maintainance costs?

Steve

Lights with low heat output
 

stevelup wrote:
The Natural Philosopher wrote:

Ian Stirling wrote:
Dave Fawthrop wrote:
On 20 Nov 2006 10:13:16 GMT, Ian Stirling wrote:

|Dave Fawthrop wrote:
| On Sun, 19 Nov 2006 23:12:53 +0000, Steve Firth
| wrote:
|
| |On 19 Nov 2006 14:33:10 -0800, wrote:
| |
| | Are there any commercialy-available low voltage lights which run cool?
| | Anything other than LEDs?
| |
| |LEDs do not run cool. No form of lighting runs cool. HTH.
|
| Depends what you mean by cool.
| LEDs do not run *cold*, (at ambient temperature) but run at a low lower
| temperature than incandescents, halogens etc, which in my book classes as
| *cool*
|
|They generally produce the same amount of heat for a given amount of
|light - it's just spread out more.

Just not true :-(
Almost all the power used by a 100W incandescent bulb goes into the room as
heat, only a tiny amount as light. Everyone who has burned a hand on a
lit light bulb will know that. A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch
You specifically mentioned LEDs, and my response was clearly about LEDs.
And the tubes of most CFLs hit 100C.
LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Hi

Surely the primary reason for using them in traffic lights is to reduce
ongoing maintainance costs?

That as well.
But there are enormous energy savings to be had as well.


Steve

Lights with low heat output
 

Lights with low heat output
 

The Natural Philosopher wrote:
snip
LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

However, this is not the case for white LEDs.
For traffic lights, it's true, for a couple of reasons.

Firstly, most of the light in a normal light is absorbed by a filter,
and secondly, the bulbs are very inefficient as they are run at a low
output to increase time between failures.

LEDs produce light at one wavelength only, so need no filters.
And the way they are used in traffic lights, where there may be hundreds
per light means that they fail gradually.

Lights with low heat output
 

The Natural Philosopher wrote:
Ian Stirling wrote:
Steve Firth wrote:
On 19 Nov 2006 14:33:10 -0800, wrote:

Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?
LEDs do not run cool. No form of lighting runs cool. HTH.

Low pressure sodium comes damn close - IIRC 80% efficient.
'normal' fluorescents are around 50%.

about 20% IIRC. LED about 10%. Incandescent about 1%.

Integrating the minimal power spectrum that looks white and gives a
reasonable colour rendition gives a hard minimum power of about 200lm/W.

Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Most white LEDs get substantially less than 15%, even under optimal
conditions. (for example, with the junction temperature at 25C, which is
unachievable in practice usually without heat pumps)

Lights with low heat output
 

The Natural Philosopher wrote:
Andrew Gabriel wrote:
In article .com,
writes:
Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?

There are low voltage fluorescents.
You haven't given enough info for any detailed reply.
LEDs you are likely to find used in most lighting are
similar efficiency to filament lamps.

Actually they are about ten times as efficient..

Nope.
Take a 500W halogen floodlight - it produces around 10000 lumens, or
20lm/W.

I'll pay you a hundred pounds for a one watt LED (to be delivered in a
couple of weeks max) that outputs 200lm.

The 'state of the art' with dodgy assumptions is around 50lm/W.

Lights with low heat output
 

LEDs do not run cool. No form of lighting runs cool. HTH.

Glow-worms do.

Lights with low heat output
 

..

Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Why do torches and headlamps with LEDs have such an improved battery
life when compared with those with incandescent bulbs? It is
certainly more than the 50% that your figures would suggest.

Lights with low heat output
 

dcbwhaley wrote:
.

Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Why do torches and headlamps with LEDs have such an improved battery
life when compared with those with incandescent bulbs? It is
certainly more than the 50% that your figures would suggest.

It's generally because small incandescent bulbs really, really suck.
They only really start to perform well at sizes of around 5W or so.

Plus - if a LED is running with a flattish battery, it produces usable
light, where a bulb just goes to a useless red glow.

Also, compare the beam patterns.
In many cases, the LED torch may produce more light, but over a narrower
area, which uses less energy.

Unfortunately, this is an area where there is a whole lot of lying going
on.

'100W' replacement spot bulbs that produce a tiny dot that's as bright
as the original light, for example, and rapidly dim over days of
on-time, because they overheat.

But even the makers of the most efficient LEDs - for example
http://www.luxeonstar.com/ don't claim more than about 1.5 times the
efficiency of large filliment bulbs, and that under somewhat optimistic
conditions. (marketing lies)

Lights with low heat output
 

In article ,
The Natural Philosopher wrote:
LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Far more likely their long life if correctly driven. If energy consumption
was important with traffic lights they'd turn them off overnight, etc.

--
*He who dies with the most toys is, nonetheless, dead.

Dave Plowman London SW
To e-mail, change noise into sound.

Lights with low heat output
 

In article .com,
wrote:
I want to light an alcove by mounting a "strip light" of some sorts on
a nearby beam. But the beam is only 4 feet above the floor so I want to
install a light which has less risk of burning or shocking the kids if
they accidentally break it.

Use a fluorescent fitting with a diffuser.

--
*I started out with nothing, and I still have most of it*

Dave Plowman London SW
To e-mail, change noise into sound.

Lights with low heat output
 

The message
from "Dave Plowman (News)" contains these words:

Far more likely their long life if correctly driven. If energy consumption
was important with traffic lights they'd turn them off overnight, etc.

In the States they installed them for energy savings. There was an
article about it in New Scientist once, or at least, a side item.
Apparently at the time LEDs were more expensive than they are now so
they only changed the red and green. The ambers weren't on long enough
to make the payback worth it.

The outcome across the whole of the union was roughly equivalent to the
output of a medium sized power station IIRC.

--
Skipweasel
Pay no attention to that man behind the curtain.

Lights with low heat output
 

In message , Dave Fawthrop
writes

A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

Leave one on for an hour or two and the grasp it firmly with your hand.
Now try and tell me they run 'warm to the touch' after you've finished
applying the bandages.
--
Clint Sharp

Lights with low heat output
 

In message , Owain
writes
wrote:
Yes, Ian, I had the same thought about mounting. With regards to a low
volt + low heat strip light though, which would you suggest I take a
look at?. There seem to be a few LED strips and that's all.

It shouldn't be hard to find a small fluoroescent fitting in a caravan
accessories shop, and 12-14V power supplies are readily available for
running car electronics / radio equipt off the mains.
Umm, no. You can get a nasty shock off a 12v fluorescent because they
usually use a step-up circuit to generate high enough voltages to get
the tube to strike and run, strike voltage can be around 600v and
running voltage is usually high enough to be dangerous if you touch the
wrong bit.

The cable between the two will need to be rated for the current at 12V
and is not necessarily safer than mains if damaged, because the high
current availability can lead to arcing.

Owain


--
Clint Sharp

Lights with low heat output
 

dcbwhaley wrote:
.
Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Why do torches and headlamps with LEDs have such an improved battery
life when compared with those with incandescent bulbs? It is
certainly more than the 50% that your figures would suggest.

I have always heard 1-2% for incandescents.

Not nearly 10%.

Cycle lamps that *pulse* make use of the fact that we can detect short
high energy light a lot better than long dim light..

Lights with low heat output
 

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Far more likely their long life if correctly driven. If energy consumption
was important with traffic lights they'd turn them off overnight, etc.

I think you should research that.

First of all there is an efficiency gain, secondly, when has any council
EVER removed or switched off a traffic light, once installed, no matter
how daft its timing, situation or whatever, been?

Lights with low heat output
 

Ian Stirling wrote:
The Natural Philosopher wrote:
Andrew Gabriel wrote:
In article .com,
writes:
Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?
There are low voltage fluorescents.
You haven't given enough info for any detailed reply.
LEDs you are likely to find used in most lighting are
similar efficiency to filament lamps.

Actually they are about ten times as efficient..

Nope.
Take a 500W halogen floodlight - it produces around 10000 lumens, or
20lm/W.

I'll pay you a hundred pounds for a one watt LED (to be delivered in a
couple of weeks max) that outputs 200lm.

The 'state of the art' with dodgy assumptions is around 50lm/W.

And Ill pay YOU a couple of hundred for a domestic lamp that isn't as
fragile as ****, that can reach ANYTHING LIKE those sorts of power
conversions.

You might as well tell me that arc lamps are actually 'incandecsnt' and
use those as a starting point.

Lights with low heat output
 

The Natural Philosopher wrote:
Ian Stirling wrote:
The Natural Philosopher wrote:
Andrew Gabriel wrote:
In article .com,
writes:
Are there any commercialy-available low voltage lights which run cool?
Anything other than LEDs?
There are low voltage fluorescents.
You haven't given enough info for any detailed reply.
LEDs you are likely to find used in most lighting are
similar efficiency to filament lamps.

Actually they are about ten times as efficient..

Nope.
Take a 500W halogen floodlight - it produces around 10000 lumens, or
20lm/W.

I'll pay you a hundred pounds for a one watt LED (to be delivered in a
couple of weeks max) that outputs 200lm.

The 'state of the art' with dodgy assumptions is around 50lm/W.

And Ill pay YOU a couple of hundred for a domestic lamp that isn't as
fragile as ****, that can reach ANYTHING LIKE those sorts of power
conversions.

http://uk.farnell.com/jsp/endecaSear...sp?SKU=4753586 as an
example of the floodlight - 9000 lm, though I've seen higher in slightly
more expensive lamps.

Or do you mean LEDs.

Lights with low heat output
 

The Natural Philosopher wrote:
dcbwhaley wrote:
.
Fluorescents get about 100lm/W, the very best white LEDs, run under laboratory
conditions get around 30lm/W, and incandescents get under about 20lm/W.

So, about 50%, 15%, and 10%.

Why do torches and headlamps with LEDs have such an improved battery
life when compared with those with incandescent bulbs? It is
certainly more than the 50% that your figures would suggest.

I have always heard 1-2% for incandescents.

This does not make it actually correct.

Not nearly 10%.

http://en.wikipedia.org/wiki/Incandescent_light_bulb
as the first source I find gives 9% for halogen.


Cycle lamps that *pulse* make use of the fact that we can detect short
high energy light a lot better than long dim light..

Only if the flicker is actually perceptible.
If they don't flicker, then they are just as bright - or perhaps less so
for LED physics reasons

Lights with low heat output
 

In article ,
Clint Sharp wrote:
A 22 watt energy saving bulb with
equivalent light output to a 100watt incandescent can only emit under 22
watts as heat. They only feel warm to the touch

Leave one on for an hour or two and the grasp it firmly with your hand.
Now try and tell me they run 'warm to the touch' after you've finished
applying the bandages.

I've got an RO80 one lighting this keyboard. It's in a metal fitting.
Which is only warm to the touch - you could leave your hand on it all day.
The previous filament lamp made the housing too hot to touch.

--
*I pretend to work. - they pretend to pay me.

Dave Plowman London SW
To e-mail, change noise into sound.

Lights with low heat output
 

In article ,
The Natural Philosopher wrote:
LEDS die at around 100C. The reason they are used increasingly in
traffic lights is energy efficiency.

Far more likely their long life if correctly driven. If energy
consumption was important with traffic lights they'd turn them off
overnight, etc.

I think you should research that.

Doesn't need research. The reason is reduced maintenance through longer
life. The energy saving is tiny in comparison to that.

First of all there is an efficiency gain, secondly, when has any council
EVER removed or switched off a traffic light, once installed, no matter
how daft its timing, situation or whatever, been?

Perhaps they would if they were really interested in saving energy. But
there isn't a meter on each set of lights, you know, so they simply don't
see any benefit of the reduced power consumption. However, they do with
maintenance costs.

--
*Who are these kids and why are they calling me Mom?

Dave Plowman London SW
To e-mail, change noise into sound.

Lights with low heat output
 

In message , "Dave Plowman (News)"
writes
Leave one on for an hour or two and the grasp it firmly with your hand.
Now try and tell me they run 'warm to the touch' after you've finished
applying the bandages.

I've got an RO80 one lighting this keyboard. It's in a metal fitting.
Which is only warm to the touch - you could leave your hand on it all day.
The previous filament lamp made the housing too hot to touch.

Right, now touch the glass.
--
Clint Sharp

Lights with low heat output
 

In article ,
The Natural Philosopher writes:
stevelup wrote:
Surely the primary reason for using them in traffic lights is to reduce
ongoing maintainance costs?

Yes. Unfortunately, the first generation turned out to be very
short lived before the LEDs died.

That as well.
But there are enormous energy savings to be had as well.

Traffic lights are not normally on a metered supply in this country.
This was an important reason in the US, where they are more often
metered, and where they use inefficient mains bulbs. UK traffic
lights have used LV halogen bulbs for decades, which are much more
efficient than mains signal bulbs in the first place.

--
Andrew Gabriel

Lights with low heat output
 

In article , Steve Firth
wrote:
LEDs do not run cool. No form of lighting runs cool. HTH.
^
/#\
Available for the retail market,
at the moment, in sizes suitable
for domestic lighting.
And even then, it's really just
painfully expensive, not
impossibly expensive.
Electro-luminescent panels are on the market with output
efficiencies up in the 90s of %, and extremely low heat output per unit
of light. Heat outputs low enough that you can't notice them. But their
sizes are limited to hand-held computers, and limited colour
availability ("white" isn't particularly white).
Cold-cathode lamps have been used in LED screens for a good few
years now, and also produce negligible heat at significantly larger
sizes than ELs are available for. Still not big enough to be usable for
room lighting, but it's getting within reach. Look at the number of 15"
and 17" flat panel computer monitors and TVs being made, and think of
the volumes of lamp production that implies - putting a flat rectangle
of cold light on the wall is already an expensive, but credible, way of
providing in-fill or mood lighting.

Oh ****, I'd better not let the wife see that.

--
Aidan
Aberdeen, Scotland
Written at Mon, 20 Nov 2006 08:35 GMT, but posted later.

Lights with low heat output
 

Owain wrote:
Dave Plowman (News) wrote:
If energy consumption
was important with traffic lights they'd turn them off overnight, etc.

Would the LED lights use sufficiently little energy they could be
powered by small turbines, or photovoltaics, on the top?

My thinking is that with self-contained traffic lights and a en
encrypted wireless networking, traffic lights could be installed and

Oh what a good idea - now traffic lights can be jammed, probably
accidentally.