Custom device request (5-10mW pulse infrared)

[Echemythia]

Could one LED each of those be cranked up in wattage to actually deliver noticeable heat? I'm thinking at least 25W or more?
I presume you're talking about an entirely different unit here. 25 watts is entirely doable with LEDs but not usually with a single LED.

If someone is actually willing to come up with plans for a programmable unit like this .......
Programming for the microcontroller is the easiest part of that build.

Fantastic. Can it be done with perhaps 4 LEDs, close to the wavelengths I mentioned above (605, 655, 715, 835)? And yes, I'm talking about a separate unit. If this can be done easier, cheaper, and quicker then I may forego the laser unit for now and try this out first. If not then an 835nm laser would be my choice.

That's really great. I have other ideas but it might raise the bar a bit. For now I should probably just stick with the LED and LD units I have in mind. When I said "programmable" I meant something where the frequency of the pulse could be programmed into the unit manually. That's a whole other animal, no?

 

[Alaskan]

Your specs:

605nm, 655nm, 715nm, and 835nm

5-10mW (switchable power?)

You can modify a constant current driver, or perhaps for LED's something to switch between lower or higher voltage output to affect the amount of power output from either a LED or laser diode. I see LED's at most of those wavelengths but have not researched the availability of laser diodes for those specific wavelengths.

Have you identified sources for either LED'S or laser diodes at those wavelengths using google searches? That should come first, then ask if they can be used for your application. You probably want to find narrowband devices close to the wavelengths of interest, not broadband. You could mix the diodes together to produce a spectrum of those wavelengths, but I am betting the individual devices should be fairly narrow. How many nm from center wavelength can these operate at to do what you want? Get that info and then search for devices.

FYI: LED's are usually broadband devices, lasers very narrowband in comparison.

 

[Echemythia]

How many nm from center wavelength can these operate at to do what you want? Get that info and then search for devices.

I singled out specifically these wavelengths because they are the peak emission and absorption spectra of the copper A protein oxidized and reduced in mitochondria. So I think it's fairly specific based on some of the spikes you can see in that article. For instance the 715nm is based on a 710-720nm peak. That said, there's also a 715-920nm broadband thing going on in there - but I'm not too worried about it either way.

If it'd be easier to go ahead and move forward with the LED unit then I'm perfectly happy with that. Perhaps that's more suited to my purposes anyway. If I had to pick one frequency for a laser unit it'd be 835nm. I'm perfectly happy with that as well.

FYI: LED's are usually broadband devices, lasers very narrowband in comparison.

I'm aware! Thanks. I may not know much about diodes but I know that much!

Have you identified sources for either LED'S or laser diodes at those wavelengths using google searches? That should come first, then ask if they can be used for your application.

Okay, I was not aware it'd fall on me to do that. What kind of criteria do I need to look for? I'm seeing LEDs at the frequencies I want. Also, I can't send links unless someone contacts me outside of this platform - unless I can send links in private messages.

 

[WizardG]

You might want to check out Luminus for high power LEDs in some of the wavelengths you're after if you really want 25 watts of LED output. Those LEDs ain't cheap though. That unit will cost quite a bit more than the 5-10mW laser unit.

Making the output of either unit programmable, in the sense of the user being able to select power, pulse width and rep' rate, is pretty straightforward using a microcontroller. For something with a single laser you could go with a simple 555 timer based circuit if you wanted to make one as cheaply as possible: one knob for rep' rate and another for pulse duration.

 

[Giannis_TDM]

I singled out specifically these wavelengths because they are the peak emission and absorption spectra of the copper A protein oxidized and reduced in mitochondria. So I think it's fairly specific based on some of the spikes you can see in that article. For instance the 715nm is based on a 710-720nm peak. That said, there's also a 715-920nm broadband thing going on in there - but I'm not too worried about it either way.

If it'd be easier to go ahead and move forward with the LED unit then I'm perfectly happy with that. Perhaps that's more suited to my purposes anyway. If I had to pick one frequency for a laser unit it'd be 835nm. I'm perfectly happy with that as well.



I'm aware! Thanks. I may not know much about diodes but I know that much!



Okay, I was not aware it'd fall on me to do that. What kind of criteria do I need to look for? I'm seeing LEDs at the frequencies I want. Also, I can't send links unless someone contacts me outside of this platform - unless I can send links in private messages.

As I have said in our pms I could be commissioned to do such a build but I am kinda afraid of doing so since its gonna be my first project for someone else, If at any time I have the spare parts ill do some experimenting with this with no cost and If it comes out good I'll give it to you.
Ill use a 555 timer circuit with a 2 way switch and a ttl capable driver, I can not give you a time estimate though cause I don't have some of the parts on hand.

 

[Alaskan]

If you just search the wavelengths of the LED’s and laser diodes available on the net which suite your needs from various sources and then try to find manufacturer specs for the spectrum the devices produce it would be easier for me to give my own opinions.

We can help point you to device sources, but you appear better qualified to choose what you might want to use as we are for the most just onlookers with no skin in the project, less you get a commitment from someone here who has enough understanding to help.

At least give some part numbers you think might work and I will see if I can find specs. Maybe that’s the bottleneck in the first place?

 

[Echemythia]

At least give some part numbers you think might work and I will see if I can find specs. Maybe that’s the bottleneck in the first place?

I can randomly select some laser diodes, sure. But I have no idea what the other criteria are for selecting a good diode. You all have the knowledge of what diodes to choose for what, etc. The only parameters I'm looking for specifically are the wattage (5-10mw) and the wavelength (835nm). And the pulse feature.

I'm not sure I ever got a clear answer on whether or not an adjustable power output is a feasible option. Would that be doable in a laser unit?

For all those following this post, please disregard the LED project I mentioned. If I decide to pursue this I will make a separate thread dedicated to that. This post is henceforth dedicated to commissioning someone for the aforementioned laser device.

To reiterate: 5-10mW (adjustable power), pulsed (switchable 500ms/1s/constant), 835nm handheld.

I had a thought that I'd like to bring up... since the laser is invisible, how will I know when the batteries are dead? Any thoughts on that?
A dim, red LED indicator somewhere on the device to indicator either that it's working when its in use or when the batteries are dead?

 

[WizardG]

If I understand how this will be used the beam specs of the diode won't matter much. Wavelength would be your first selection criteria with cost as your second. A laser that's used at point blank range won't need much in the way of optics if focusing is even needed at all.

 

[paul1598419]

If you aren't nailed down to a 835nm diode, go with a 808nm one. They are very common, inexpensive, and the smaller ones can be driven that low. I don't see much use for a 10 mW laser for use on yourself. The power levels are just too low.

 

[Echemythia]

If I understand how this will be used the beam specs of the diode won't matter much. Wavelength would be your first selection criteria with cost as your second. A laser that's used at point blank range won't need much in the way of optics if focusing is even needed at all.

Good to know. I don't even really know what you mean by "beam specs" but sure! You are correct about point blank range.

If you aren't nailed down to a 835nm diode, go with a 808nm one. They are very common, inexpensive, and the smaller ones can be driven that low. I don't see much use for a 10 mW laser for use on yourself. The power levels are just too low.

As I've said before, I get great results with a 5mW device. A class IIIA laser is the basic model purchased by most practitioners for basic low-level laser therapy. 10mW would be twice as strong as what I use now. That said, I'm reviewing some of the scientific literature and there's always a possibility I could be talked into a stronger device.

Also, I am kind of beholden to 835nm. Are these quite expensive? I saw one that was $140 and that's a bit much for this first commissioned device.

 

[Snecho]

I know you now stated that you decided to go for the laser option but I just wanted to point out that just a single 25W LED is as big as half a CD and needs a baseball size chunk of heatsink to work. Having 4 in a handheld unit would be near impossible from what I know.

 

[Echemythia]

I know you now stated that you decided to go for the laser option but I just wanted to point out that just a single 25W LED is as big as half a CD and needs a baseball size chunk of heatsink to work. Having 4 in a handheld unit would be near impossible from what I know.

Lol, excellent. I've learned a lot from you folks already. Thanks.

 

[WizardG]

I know you now stated that you decided to go for the laser option but I just wanted to point out that just a single 25W LED is as big as half a CD and needs a baseball size chunk of heatsink to work. Having 4 in a handheld unit would be near impossible from what I know.

I would point you to Luminus LEDs. They make large single die LEDs. Example: SST-90-W, a 60 watt part with a single 3x3mm die on a MCPCB measuring 10x11 mm. But yeah, you'll still need a lot of heatsink to run it CW at rated power. For a pulsed application like this though you could put it in a handheld relatively easily as long as the duty cycle wasn't too high. Batteries though..........

They make some IR LEDs rated @ 850 nm.

 

[Snecho]

I would point you to Luminus LEDs. They make large single die LEDs. Example: SST-90-W, a 60 watt part with a single 3x3mm die on a MCPCB measuring 10x11 mm. But yeah, you'll still need a lot of heatsink to run it CW at rated power. For a pulsed application like this though you could put it in a handheld relatively easily as long as the duty cycle wasn't too high. Batteries though..........

Thay make some IR LEDs rated @ 850 nm.

Yeah, I did take a look at that site. Pretty cool. It's just the red nm ones I've seen that DTR sells are on a large chip with lots of wires and a huge chunk of heatsink that look pretty ridiculous. But as you said heatsinking and batteries...not very portable in the end I'm afraid.

In any event this does sound like a pretty tempting business opportunity to whomever. And the 835nm laser version seems an easy enough concept. Very tempting indeed...

 

[Echemythia]

In any event this does sound like a pretty tempting business opportunity to whomever. And the 825nm laser version seems an easy enough concept. Very tempting...

Um, yes. I'm offering to buy more than one. Lol. I'll have you know what we are piecing together here is my dream-laser for photobiomodulation. Just sayin'. If these could be mass-produced and I'm satisfied with the product I may even invest or team up with the builder. If you are catching what I'm saying and you are interested, you should PM me.

Note: 835nm is what I'm really looking for.

 

[WizardG]

Would 830nm be close enough: https://www.ebay.com/itm/830nm-30mW...532662?hash=item1efd0d6636:g:HOoAAOSw8gRdEX77

And just a thought here, a ground glass or other translucent (not transparent) window on the front of your device would render it 'eye safe'. As you know the IR wavelengths you're after are not very visible, but anything above 5mW is considered a hazard to our eyes. The diffusing window would prevent the laser output from being focused by the eye to a hazardous concentration of light on the retina. I imagine the diffusing window being placed directly on the skin so there wouldn't be any reduction in the amount of light being delivered to the 'patient' but there would be no 'beam' that could damage anyone's eyes. You'd be able to crank up the power a bit too without creating a dangerous device with an eye-killing invisible beam. The module above is rated for 30mW @ 830nm and it's cheap.