Infrared LED and driver for Convoy S2+

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Nisei
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Infrared LED and driver for Convoy S2+

Hey guys

I have a blue Convoy S2+ with Nichia 365nm UV LED and an added 365nm UV pass filter.
I just bought a black version since they only sell them in black, and switched to a blue host and added the filter.

So now I would also like an 850nm infrared version in a red host but the problem is they don’t sell any infrared versions, nor can I find an infrared drop-in for the S2+
What’s the right way to acomplish something like this? I can solder SMD but I have no idea what parts I need. Or is it possible to buy a different IR flashlight on eBay and transfer the parts to an S2+?

Any help would be appreciated.
Thanks in advance!

ggf31416
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You can get IR leds from Mountain Electronics. For the S2+ you will need a 16mm MCPCB/Star.

http://www.mtnelectronics.com/index.php?route=product/category&path=60_105

Currently the 850nm version is not available, only the 940nm version.
There is a warning in the product page you must follow, so you should also get some non-conductive thermal product:

Quote:
This version must be electrically isolated from the ground/pill of your flashlight or whatever device you install it in!…. You can electrically isolate using a thin layer of Arctic Alumina thermal epoxy or a silicone/fiberglass thermal pad in combination with the thermal epoxy (recommended configuration). ALWAYS check for electrical conductivity between ground/pill and LED+/BATT+ before powering!

There is a 850nm led available in kaidomain , it doesn’t show any warning but I would expect that the same goes for it.

There is also a OSRAM led in fasttech , but only in 20mm or as bare led. IR leds are not hard to find, so I would expect that any of the more specialized electronics companies you can find in the forum would have them as well.

MtnElectronics recommends no more than ~1A maximum current for the leds (3×7135=1.05A is ok). Unless you know better or don’t care if the led dies I would follow that recommendation.

nofearek9
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cheap solution is to buy this : https://www.fasttech.com/p/7261900 and transfer the led to a 16mm pcb which is NOT dtp.
this might work https://www.fasttech.com/products/1611/10006929/1554904-16mm-aluminum-ba... test the pcb to be sure its NOT dtp.

easiest solution will be to ask http://www.mtnelectronics.com build it for you.

TBone
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Led4power has brand new emitter boards that solve the problem that Oslon and Luxeon IR LEDs have non-neutral mid pads. (20 mm boards so you will have to mod the pill and maybe the board)
Their drivers are a bit overkill as your maximum current will be much lower.

You may use a genuine 17 mm Convoy driver and reduce the number of 7136 current regulators on it.

More on the best LEDs later…

Lexel
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Those Oslon and Luxeon Emitters can work on DTP stars

But you need a driver that has the battery positive on the tail and ground on the driver spring
the Biscotti Attiny 13a should be fine with a drive current of 1.4A if played safe and 2100mA with driving LED harder, but should be good on DTP
I did such designs

for Osram IR emitters with Anode on thermal pad

Osram DTP driver Tripledown (TA Bistro/Bistro HD OTSM 3 Channel compatible)

Inverted FET + n 7135

Inverted Biscotti single channel

Lexel
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pony wrote:
You should get the one in 940nm. At 850nm some light is still visible to the human eyes. Just like on the 365nm Nichia.

depends on the gear he uses, most NV and cameras only get high brightness with 850nm
Those quality 850nm IR LEDs have almost no visible spectrum far better than even Nichia UV ones

IR LEDs also have not the white wastelight issues like many cheap UV LEDs

Hunter
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What can you do with IR led?
Does it needs to be focused (in reflector) or you could build S2+ tripe IR with Carclo triple lense!

Henk4U2
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First question should be (IMHO): what do you need it for?

With UV it’s simple. Though it can damage your eyes, you cannot really see it. But you can see the reflection of it.
IR you cannot see, nor the reflection of it. So you need something to see it with.
Do you own night goggles or do you use a camera. First you have to determine at what wavelenght these operate.
The usual suspects are: 850nm and 940nm.

Only then question two is in order: how do I achieve that (see previous posts). Light, LED, driver, et cetera.

I always think long and hard before I say something really stupid.

Lexel
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there are different powerful Osram LED chips

only the 471XAS have 1.5A drive current
so this one is 850nm only so far, no 940nm 1.5A diode released yet

I would still stick this diode into a Convoy C8 host
http://www.kaidomain.com/p/S026840.Osram-SFH-4716AS-IR850nm-IR-Emitter-w...

the shallow dome with reflector gives a lot more throw than this zoom light

but the star has to be mounted with an insulation foil like Kapton tape or use a reverse polarity driver like the one I designed

Lexel
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if you insulate the stars back and screws you can use a normal XML2 C8 7135*6 to use as host for like 14$

all you need is solder iron, some Kapton tape and small insulation washers
also filing the screw slots on the board wider so there is no risk the screws touching the LED board

Sirius9
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pony wrote:
Is it easy to do that for someone who has no experience in building lights?
It’s just like playing the game for the first time, you get shot several times but each time you learn what you need to watch for Big Smile Btw, you can just use cheap non-DTP MCPCB to solder led and a bit weaker driver (don’t push the led so hard), then you won’t need kapton tape.
pony wrote:
Would a Convoy S2+ host work too ?

Yes, but you need 16mm MCPCB for S2+ and maybe use SMO reflector.

 

Lexel
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the thing is there are no presoldered LEDs on non DTP boards

and reflowing is not that easy for first mod

Sirius9
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I just found that I have two 350nm Osram leds (SFH4715AS) that made me happy Big Smile

 

Nisei
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Thanks for all the responses guys, I really appreciate the help!!!

Henk4U2 wrote:
First question should be (IMHO): what do you need it for?
Just fun to have one.
And I have modified a Sony Nex3-N camera to full spectrum so that camera will be able to register the IR light.

pony wrote:
You should get the one in 940nm.
At 850nm some light is still visible to the human eyes.
Just like on the 365nm Nichia.
If the LED still produces some light in the visible spectrum it’ll get filtered out by the 850nm pass filter I’m going to use. I’ve also done this with my Nichia (365nm filter of course) and it has reduced the visible light to a minimum.

Sirius9 wrote:
I just found that I have two 350nm Osram leds (SFH4715AS) that made me happy Big Smile
You mean 850nm Smile
So what are you going to do with them?
I’ve thought about buying all parts to make my own but I have no idea about drivers etc. I even had to look up what DTP means Big Smile
So all the help offered with regards to building one myself is much appreciated but I still have a lot of catching up to do.

Looking at the size I need, I think this model may be easy to have its guts transplanted to a Convoy S2+
$10 18650 IR flashlight on eBay
However, there’s not a word on which LED it contains and its rated power is probably bloated.

ggf31416
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Nisei wrote:
I’ve thought about buying all parts to make my own but I have no idea about drivers etc. I even had to look up what DTP means Big Smile So all the help offered with regards to building one myself is much appreciated but I still have a lot of catching up to do.

If the battery is connected directly to the led and the forward voltage (Vf) of the led is lower than the voltage of the battery, then the led will take an huge amount of current and will likely be damaged. As a general rule the higher the wavelength the lower the Vf, so IR leds have a very low Vf.

The driver regulates the current so that doesn’t happen, also controlling modes in flashlights with several modes. Lineal drivers burn the excess voltage as heat to keep the current regulated. They are somewhat inefficient for low Vf leds but they fit in small flashlight and are cheap so they are quite popular. 7135 chips in linear drivers are connected in parallel and each one allows passage of 350mA of current (in some models 380mA), so a driver with 3 7135 chips will give 350×3 = 1050mA = 1.05A of current to the led.

DTP means direct thermal path. It means that the star (also known more formally as MCPCB) has copper or other highly conductive material underneath the led that continues all the way to the back of the star, so the heat can go quickly from the led to the back of the star and then to the pill, avoiding overheating of the led and allowing higher currents. The problem is that copper conducts electricity as well as heat. That’s not a problem for cree or nichia leds, but it is for OSRAM ones.

Nisei wrote:
Looking at the size I need, I think this model may be easy to have its guts transplanted to a Convoy S2+ $10 18650 IR flashlight on eBay However, there’s not a word on which LED it contains and its rated power is probably bloated.

In that case I would get something like Manta Ray Osram IR850nm and just use it as it is. Unless everything fits exactly, “transplanting guts” is not easier than making your own in the first place.

Nisei
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ggf31416 wrote:
The driver regulates the current so that doesn’t happen, also controlling modes in flashlights with several modes. Lineal drivers burn the excess voltage as heat to keep the current regulated. They are somewhat inefficient for low Vf leds but they fit in small flashlight and are cheap so they are quite popular. 7135 chips in linear drivers are connected in parallel and each one allows passage of 350mA of current (in some models 380mA), so a driver with 3 7135 chips will give 350×3 = 1050mA = 1.05A of current to the led.
Ah cool. So this is regardless of the voltage you supply?
So an LED with a 1.2V forward voltage can be driven by either a 1.2V NiMH or a 3.7V Li Ion and use a constant current of 1.05A when using 3× 7135 regulators?
That’s the most basic thing I need and I assume a controller chip with firmware is only used when you want more modes on a flashlight?

ggf31416 wrote:
DTP means direct thermal path. It means that the star (also known more formally as MCPCB) has copper or other highly conductive material underneath the led that continues all the way to the back of the star, so the heat can go quickly from the led to the back of the star and then to the pill, avoiding overheating of the led and allowing higher currents. The problem is that copper conducts electricity as well as heat. That’s not a problem for cree or nichia leds, but it is for OSRAM ones.
Thanks for the useful information.

ggf31416 wrote:
In that case I would get something like Manta Ray Osram IR850nm and just use it as it is.
Unless everything fits exactly, “transplanting guts” is not easier than making your own in the first place.
Thanks for the tip, I“ve ordered one anyway. It’s cheap and I’m certain to get an Osram LED. Perhaps if I take it apart and see how it’s done I find it to be no problem making one myself.
Lexel
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Nisei wrote:
ggf31416 wrote:
The driver regulates the current so that doesn’t happen, also controlling modes in flashlights with several modes. Lineal drivers burn the excess voltage as heat to keep the current regulated. They are somewhat inefficient for low Vf leds but they fit in small flashlight and are cheap so they are quite popular. 7135 chips in linear drivers are connected in parallel and each one allows passage of 350mA of current (in some models 380mA), so a driver with 3 7135 chips will give 350×3 = 1050mA = 1.05A of current to the led.
Ah cool. So this is regardless of the voltage you supply? So an LED with a 1.2V forward voltage can be driven by either a 1.2V NiMH or a 3.7V Li Ion and use a constant current of 1.05A when using 3× 7135 regulators? That’s the most basic thing I need and I assume a controller chip with firmware is only used when you want more modes on a flashlight?

This is wrong AMCs have minimum voltage specified with 2.7V good ones regulate even moon down to 2.3V bad ones quite moon at about 2.9V

never tested lower voltages as I kept to lithium LVP test with power supply on my driver build

ggf31416
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Nisei wrote:
Ah cool. So this is regardless of the voltage you supply? So an LED with a 1.2V forward voltage can be driven by either a 1.2V NiMH or a 3.7V Li Ion and use a constant current of 1.05A when using 3× 7135 regulators? That’s the most basic thing I need and I assume a controller chip with firmware is only used when you want more modes on a flashlight?

In principle yes for the concept of linear drivers, but I don’t think there is a led with such a low Vf. In practice 7135 also have a bit of voltage loss of their own, so the battery voltage has to be a bit higher than what the led requires. AFAIK they can’t handle more than ~5.5-6V without modifications and as Lexel said, they need a minimum voltage to work as any electronic component.

7135s adapt their resistance automatically to try to keep the current constant, so they don’t need to be finetuned for the Vf range of each led. The Vf is a function of (desired) current or in other words forward current is a function of the voltage that reaches the led, for example a led could take 700mA at 3.0V, 1050mA at 3.2V and 2800mA at 3.6V. If the battery is at 4.0V a driver with 3×7135 will transform the extra 0.8V into heat to keep 1050mA, one with 8×7135 will only need to transform 4.0 – 3.6 = 0.4V to keep current at 8×350 = 2800mA. When the battery (counting losses) goes below such voltage the current will fall accordingly. See for example this test by djozz for the Vf curves of several white leds (the lines in a lighter shade are Vf as function of current, the solid colors are output in lumens).

If you want to run a led with one or two 1.2V batteries you need to use a boost driver. They increase the voltage to what is needed. I don’t really know much about boost drivers. AFAIK small boost drivers can’t handle much current but they may be able to handle 1A output current.

Nisei
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ggf31416 wrote:
In principle yes for the concept of linear drivers…
Thanks again for all the useful info!
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Lexel wrote:
Nisei wrote:
ggf31416 wrote:
The driver regulates the current so that doesn’t happen, also controlling modes in flashlights with several modes. Lineal drivers burn the excess voltage as heat to keep the current regulated. They are somewhat inefficient for low Vf leds but they fit in small flashlight and are cheap so they are quite popular. 7135 chips in linear drivers are connected in parallel and each one allows passage of 350mA of current (in some models 380mA), so a driver with 3 7135 chips will give 350×3 = 1050mA = 1.05A of current to the led.
Ah cool. So this is regardless of the voltage you supply? So an LED with a 1.2V forward voltage can be driven by either a 1.2V NiMH or a 3.7V Li Ion and use a constant current of 1.05A when using 3× 7135 regulators? That’s the most basic thing I need and I assume a controller chip with firmware is only used when you want more modes on a flashlight?

This is wrong AMCs have minimum voltage specified with 2.7V good ones regulate even moon down to 2.3V bad ones quite moon at about 2.9V

never tested lower voltages as I kept to lithium LVP test with power supply on my driver build

I bought a couple of AMC7135 Chips with a Claw Logo from Aliexpress, Are they good ?

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The one you found at eBay is also available at Fasttech:
https://www.fasttech.com/products/1/10049037/9632762-courui-infrared-led...
Named there as “COURUI”. There are 3 models with IR LED just recently added.
If I could think of any reason to own one, I would have ordered it already …