Infared light for night time
 

Diagram here if anyone interested? it can be made up on veroboard if you are
not bothered about a PCB one.

The more leds on the cicuit the better the night vision.
http://www.reject.org/tsd/liz/gbppr/...v/ir_illum.pdf

Infared light for night time
 

"George" wrote in message
.uk...
Diagram here if anyone interested? it can be made up on veroboard if you
are
not bothered about a PCB one.

The more leds on the cicuit the better the night vision.
http://www.reject.org/tsd/liz/gbppr/...v/ir_illum.pdf




Whats the best infareds for this project,Blue or Clear? as I found this site
out of a few to be a lot cheaper in price.

http://www.esr.co.uk/Optoelectronics.PDF

TA

Infared light for night time
 

On Thu, 31 Jan 2008 17:44:11 +0000, George wrote:

"George" wrote in message
.uk...
Diagram here if anyone interested? it can be made up on veroboard if
you
are
not bothered about a PCB one.

The more leds on the cicuit the better the night vision.
http://www.reject.org/tsd/liz/gbppr/...v/ir_illum.pdf




Whats the best infareds for this project,Blue or Clear? as I found this
site out of a few to be a lot cheaper in price.

http://www.esr.co.uk/Optoelectronics.PDF

TA

Probably part number 720-530 on page 21. Those will give 80mW radiant
power each, if you adjust the resistors to put 100mA through each string
of LEDs. Using a 12v supply you could make R1-R8 15 ohms rather than 39
ohms. This is running them close to their maximum so perhaps a slightly
higher value may be better... Note that your total load current would be
400mA, so this isn't really for battery operation.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info http://mixpix.batcave.net

Infared light for night time
 

mick wrote:
On Thu, 31 Jan 2008 17:44:11 +0000, George wrote:
"George" wrote in message
.uk...

Diagram here if anyone interested? it can be made up on veroboard if
you
are
not bothered about a PCB one.

The more leds on the cicuit the better the night vision.
http://www.reject.org/tsd/liz/gbppr/...v/ir_illum.pdf




Whats the best infareds for this project,Blue or Clear? as I found this
site out of a few to be a lot cheaper in price.

http://www.esr.co.uk/Optoelectronics.PDF

TA

Probably part number 720-530 on page 21. Those will give 80mW radiant
power each, if you adjust the resistors to put 100mA through each string
of LEDs. Using a 12v supply you could make R1-R8 15 ohms rather than 39
ohms. This is running them close to their maximum so perhaps a slightly
higher value may be better... Note that your total load current would be
400mA, so this isn't really for battery operation.

Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT

Infared light for night time
 

wrote in message


Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT

Hmmm! yes I can see my electricity bill now. ;-)

ps I don't want to resemble part of blackpool illuminations

Infared light for night time
 

George wrote:
wrote in message


Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT


Hmmm! yes I can see my electricity bill now. ;-)

ps I don't want to resemble part of blackpool illuminations

unclear how thats relevant here. Filament lamps are about as
efficient as LEDs at IR.


NT

Infared light for night time
 

wrote in message
...
George wrote:
wrote in message


Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT


Hmmm! yes I can see my electricity bill now. ;-)

ps I don't want to resemble part of blackpool illuminations

unclear how thats relevant here. Filament lamps are about as
efficient as LEDs at IR.


NT

IR Leds will last cosiderably a lot longer than filament bulbs.

Infared light for night time
 

On Fri, 01 Feb 2008 19:50:30 +0000, George wrote:

wrote in message
...
George wrote:
wrote in message


Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT


Hmmm! yes I can see my electricity bill now. ;-)

ps I don't want to resemble part of blackpool illuminations

unclear how thats relevant here. Filament lamps are about as efficient
as LEDs at IR.


NT

IR Leds will last cosiderably a lot longer than filament bulbs.


I suspect that they will be much more efficient than filament bulbs as
the energy produced is monofrequency and the beam width is quite narrow
(40 degrees for the part number given). Filament bulbs waste a lot of
power radiating well into the visible region (even at half voltage) and
also radiate in all directions.

It would be interesting to test this.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info http://mixpix.batcave.net

Infared light for night time
 

In message , George
writes

wrote in message
...
George wrote:
wrote in message


Why use LEDs when filament lamps radiate IR well when run at under
half rated voltage. Producing IR is the filament lamp's forte, or
weakness when you want visible.


NT


Hmmm! yes I can see my electricity bill now. ;-)

ps I don't want to resemble part of blackpool illuminations

unclear how thats relevant here. Filament lamps are about as
efficient as LEDs at IR.


NT

IR Leds will last cosiderably a lot longer than filament bulbs.

How much longer will a filament lamp last at 50% it's rated voltage ?

--
geoff

Infared light for night time
 

In message , writes
On 1 Feb,
geoff wrote:

How much longer will a filament lamp last at 50% it's rated voltage ?

From experience of using two in series in a past life, I'd say for ever,
unless they were 15w pigmy.

S'wot I was thinking

I used to use pigmys as loads for soak tests and found that even they
lasted almost forever when run at lower voltages


--
geoff