Advice on LEDs for the hard of thinking

  • Thread starter J T Pearson Outdoor Train
  • Start date
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J T Pearson Outdoor Train

Guest
I am looking for some advice and a basic circuit to convert a conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
 
"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message
news:Zq6Jc.182$N77.119217@news.xtra.co.nz...
I am looking for some advice and a basic circuit to convert a conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
Click to expand...
Probably better to buy one, like don't re-invent the wheel :)
However if it's a personal 'Quest', basically if you are using the high
output white leds there are several approaches. You can drive combinations
of LED's by connecting them in parallel with a current limiting resistor in
series with each.
Many designs for 'pulsed current' circuits have been advanced.
Really you have not given much information like how many cells and type you
plan to use.
There are many combinations and battery styles out there !!

--
Regards ........... Rheilly Phoull
 
What I'm trying to do is convert an old Petzl head torch to LED. They take a
4.5v MN1203 battery as standard but I also have an adaptor to use 3no AA
cells instead.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:2lkd0gFdhn5qU1@uni-berlin.de...
"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message
news:Zq6Jc.182$N77.119217@news.xtra.co.nz...
I am looking for some advice and a basic circuit to convert a
conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of
blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz



Probably better to buy one, like don't re-invent the wheel :)
However if it's a personal 'Quest', basically if you are using the high
output white leds there are several approaches. You can drive combinations
of LED's by connecting them in parallel with a current limiting resistor
in
series with each.
Many designs for 'pulsed current' circuits have been advanced.
Really you have not given much information like how many cells and type
you
plan to use.
There are many combinations and battery styles out there !!

--
Regards ........... Rheilly Phoull
Click to expand...
 
"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message
news:lh8Jc.224$N77.121419@news.xtra.co.nz...
What I'm trying to do is convert an old Petzl head torch to LED. They take
a
4.5v MN1203 battery as standard but I also have an adaptor to use 3no AA
cells instead.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:2lkd0gFdhn5qU1@uni-berlin.de...

"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message
news:Zq6Jc.182$N77.119217@news.xtra.co.nz...
I am looking for some advice and a basic circuit to convert a
conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of
blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz



Probably better to buy one, like don't re-invent the wheel :)
However if it's a personal 'Quest', basically if you are using the high
output white leds there are several approaches. You can drive
combinations
of LED's by connecting them in parallel with a current limiting resistor
in
series with each.
Many designs for 'pulsed current' circuits have been advanced.
Really you have not given much information like how many cells and type
you
plan to use.
There are many combinations and battery styles out there !!

--
Regards ........... Rheilly Phoull




Sounds borderline to me :) I seem to recall that the headsets are about
Click to expand...
A$10 on Ebay.(Plus post)
Prolly time to update ??
--
Regards ........... Rheilly Phoull
 
"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message news:<lh8Jc.224$N77.121419@news.xtra.co.nz>...
What I'm trying to do is convert an old Petzl head torch to LED. They take a
4.5v MN1203 battery as standard but I also have an adaptor to use 3no AA
cells instead.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:2lkd0gFdhn5qU1@uni-berlin.de...

"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in message
news:Zq6Jc.182$N77.119217@news.xtra.co.nz...
I am looking for some advice and a basic circuit to convert a
conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of
blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz



Probably better to buy one, like don't re-invent the wheel :)
However if it's a personal 'Quest', basically if you are using the high
output white leds there are several approaches. You can drive combinations
of LED's by connecting them in parallel with a current limiting resistor
in
series with each.
Many designs for 'pulsed current' circuits have been advanced.
Really you have not given much information like how many cells and type
you
plan to use.
There are many combinations and battery styles out there !!

--
Regards ........... Rheilly Phoull
Click to expand...
There are special ICs to power multiple LEDS with equal brightness -
have a look at the Linear Technology and Maxim/Dallas websites for
details.

Fred.
 
"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in
message news:Zq6Jc.182$N77.119217@news.xtra.co.nz...
I am looking for some advice and a basic circuit to convert a
conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of
blue,
white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
Click to expand...
Nichea white LEDs (model NSPW515BS) have a forward voltage drop of
around 3.6V, with a test current of 20mA. If you use 6 to 10 of them,
your torch will require between 120mA and 200mA. With a 4.5V supply,
each LED will need a 47 ohm resistor. The resistor can be on either
side of the LED.

These NSPW515BS LEDs cost about $1 US each. You can get cheaper ones
on EBAY, but according to recent experiments, they aren't going to
last as long.

Regards,
Bob Monsen
 
What's that Lassie? You say that J T Pearson Outdoor Training fell
down the old sci.electronics.basics mine and will die if we don't
mount a rescue by Wed, 14 Jul 2004 20:47:56 +1200:

I am looking for some advice and a basic circuit to convert a conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of blue,
white & amber. Guidance greatly appreciated.
Click to expand...
Look here:
http://www.candlepowerforums.com/

--

Dan
 
Robert C Monsen wrote:

"J T Pearson Outdoor Training" <jtpoutdoor@xtra.co.nz> wrote in
message news:Zq6Jc.182$N77.119217@news.xtra.co.nz...

I am looking for some advice and a basic circuit to convert a
conventional
torch to LED. I want to use 6-10 white LEDs or possibly a mixtire of

blue, white & amber. Guidance greatly appreciated.

--
Jane Pearson & Bill Wheeler
J T Pearson Outdoor Training
12 Mountfort Street
Outram
New Zealand
Tel. 643 486 1363
jtpoutdoor@xtra.co.nz
Click to expand...

Nichea white LEDs (model NSPW515BS) have a forward voltage drop of
around 3.6V, with a test current of 20mA. If you use 6 to 10 of them,
your torch will require between 120mA and 200mA. With a 4.5V supply,
each LED will need a 47 ohm resistor. The resistor can be on either
side of the LED.

These NSPW515BS LEDs cost about $1 US each. You can get cheaper ones
on EBAY, but according to recent experiments, they aren't going to
last as long.
Click to expand...
Nichia NSPW500BS white LEDs are available from www.whitelightled.com for
a dollar each. This 500 is different from the 515 in that the beam is
narrower, which is more appropriate for flashlights/torches. I've
bought several hundred from him with no problems. The Hong Kong ones
from Ebay are junk. :-(

I use 33 ohm resistor in series with each for three AA cells because the
voltage drops a bit when several LEDs are connected in parallel.

Regards,
Bob Monsen
Click to expand...
 
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