Help regarding choosing solution for adding UVA/UVB LED's to a DIY COB LED grow light.

nachooo said:

Just found it

The mutated one versus the normal one..well even the normal one is a little changed

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I did not try to plant any of them as they will probably be hermies anyway(like her mother). It is quite possible that the seedlings also show mutations or are not viable at all. One would have to try that.
Many seeds look quite normal too. I found most of the deformed ones were only in the tops where the UV radiation was the strongest.

You are right, it come from the top..the ones below were normal.

nachooo said:

You are right, it come from the top..the ones below were normal.

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I'll soak a few beans at the next opportunity just to see what happens...

Well if you see crystals over the cotyledons report us it as son as posible

pulling up a chair for mutated seeds

Thank you for all answers, sorry for being absent for so long.

@Airwalker16
Good suggestion, I hit a brick wall when looking for around 30mA adjustable LED drivers, this has 30mA as it's minimum(31mA actually IIRC) which might work just fine. Although this suggestion sparked ideas that has now ended up in me thinking that I will be best of using a simple LM317(or similar) linear voltage regulator in the "constant output current" configuration which simply connects a resistor between the regulators output and it's ADJ terminal/pin to regulate the current out of the output.
I will need to create a around 12V rail for my system anyway and it seems far easier to use such a DIY'ed linear constant current source than to buy a DC-DC converter although in the end a switching DC-DC converter of one kind or another will be used.


I have been talking to a guy at a hydro store and he's idea is similar to at least 1 of the answers in this thread, which is to not do as I first intended and calculating the amount to the best of my ability with the intention of running the UV LED's the hole time the white COB's are lit and instead run them something like 30min each time and x times a day and experiment to see when the leafs start to show sun-burn which apparently should be very visible and easy to spot. Experiment with the duration of each period and also the number of periods, or just decide upon 30min 3 times a day and if that isn't too much then test 40min 3 times a day, or similar.

But I am considering to not get one of those

I'll also like to add that I am far from a beginner when it comes to electronics, I am very comfortable with this situation and I foresee no problems or hazards to my person.

But I do have gotten a headache from this LED selection, oh wait, first up, why don't I go with tubes?

Well I already have problems from my grow light being too strong and in that situation I really don't need the extra 400nm - 700nm light, instead I really like to avoid that.

Also my budget is such that LED's although possibly more expensive in the long run is cheaper in regards to the initial investment which I am able to afford right now.

But I am already in week 3 of flowering and I had hoped to be able to expose the plant to UV the last few weeks, if I decide upon a solution(which LED's and what drivers) then I can have the system up an running within a week.
But it almost sounds as I might be too late already for this grow?


In any case, these are the range of choices.
UVA:
LST1-01G01-UV01-00, 365nm, 875mW $21.80
LST1-01G01-UV02-00, 385nm, 1015mW $11.48
LST1-01G01-UV03-00, 395nm, 1015mW $11.48
LST1-01G01-UV04-00, 405nm, 930mW $11.48
(at Digi-key)

MTSM340UV-F5120S, 340nm, 55mW $57.8
(at Digi-key)

UVB:
MTSM275UV-F1120S, 275nm, 2mW $54.60
MTSM285UV-F1120S, 285nm, 2mW $54.60
MTSM295UV-F1120S, 295nm, 2mW $54.60
MTSM310UV-F1120S, 310nm, 2mW $54.60
(at Digi-key)

RVXP1-280-SB-075408, 280nm, 18mW $81.00
(at digi-key)


But I am considering to not get one of MTSMxxxUV-F1120 UVB LED's and instead maybe get one of each of:

If I would go with all 4 LST1-01G01 UVA LED's which I think(without actually having a clue) would be much more than enough if driven at 500mA which at an unknown distance sums up to(according to the datasheet, if the values are simply added):
3835mW
12,42µMol/s
7,22µMol/J

I don't know if it is even relevant that around the equator at sea-level the surface of the earth sees about 6% UV out of which 5,7% is UVA and 0,3% is UVB, but I have found other values which was sort of 50% of those numbers.

I am sort of considering ether getting all those 4 previously mentioned UVA LED's or to get 1 RVXP1-280-SB-075408 which outputs 18mW and 1, maybe 2 of the UVA LED's.

But I find that 340nm 55mW LED(MTSM340UV-F5120S) to be interesting, I have read some claims that UVA can do the same job as UVB but I don't know what to believe, at least that one is in the lower spectrum of UVA closer to UVB than the others.

I am quite confused right now so I will sleep upon this, but if anyone have any suggestions or opinions regarding what you would think is a good choice granted that I can spend max $100, sort of I would love to hear what you think.

Thank you very much for all the activity in this thread, I really appreciate and enjoy the conversations.

I would only use three wavelength 290, 340 and 365nm. Below is a screeny from an Arcadia reptile bulb and it's known that their spectrum works. If it's possible to do it better? For sure! But without more knowledge about this topic I would try to mimic it and good. Maybe there will be some scientific research about UVB soon as there is a lot of demand right now also in the professional area and many users want's to optimize their crop quality.

And this is the spectrum from and Agromax PureUV bulb. As you can see there is almost no light below 280nm and I would not use near UVC light too because it's realy dangerous.

Humple said:

Anyone have any idea of the effective lifespan of some of these UV diodes?

Airwalker16 said:

I'm sure it's similar to other LEDs. 10's of 1,000's of hours.

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In my experience UVb leds last anything from 50 or so hours to a few hundred depending on how they're driven but more importantly the lower the wavelength the shorter their life.
UVa diodes are still going but I've no intention of ever replacing the UVb as they simply don't last long enough given their prices

I have a plan, first of I want to tell you about my safety features.

I will install a magnetic sensor(don't know the name but those that are often used for home-alarm systems where there are 2 peaces, one magnet and one receiver which senses if the magnet is close or not, perhaps a reed-switch) on my tent so that the microcontroller which is controlling the ON/OFF of the UV LED's.
So the UV LED's will only be allowed to be active when the door to the tent is closed, I really like this idea, and I will use a RTC clock to determine when and if the LED's should be active, and experiment with duration of activation and number of occurrences each day.

I haven't decided yet if I will dim the LED's with PWM from the microcontroller or using a potentiometer, in ether case I will have the option of dimming in order to dial in the best characteristics of the UV exposure.

SSR said:

In my experience UVb leds last anything from 50 or so hours to a few hundred depending on how they're driven but more importantly the lower the wavelength the shorter their life.
UVa diodes are still going but I've no intention of ever replacing the UVb as they simply don't last long enough given their prices

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This makes me think that paying $81.00 for a 280nm diode is a mistake.
Could you elaborate a little about what you mean by "how they're driven"?
Do they last longer if I reduce the current somewhat?


Let me ask this, is there any reason to think that it wouldn't/couldn't work out pretty much the same if I exposed my plant to periods of UVA light using all 4 of the LST1-01G01 series?
LST1-01G01-UV01-00, 365nm, 875mW $21.80
LST1-01G01-UV02-00, 385nm, 1015mW $11.48
LST1-01G01-UV03-00, 395nm, 1015mW $11.48
LST1-01G01-UV04-00, 405nm, 930mW $11.48

I am actually leaning towards getting the above mentioned 365nm, 385nm, 395nm and 405nm diode starboards and use that too see if I get any results, the thing is that I am not an experienced grower so I can't tell if it works or not(I'm on my first grow). The UVB LED is so very expensive and what if I would only get 50h or 100h out of it, that would feel like wasted money.

I have found my self feeling that I should add UV ASAP, the flowers of my first plant have begun developing.
As long as I order early during the coming week(alright it is Monday already where I live anyway) I will get the UV LED's up and running during the coming weekend.

I will go ahead and order those 4 UVA LED's as well as a suitable driver, I can add UVB later in case the conclusion becomes that UVB is needed rather than only UVA.

Edit:
Mean-Well have a very nice driver called LCM-40 which features a selectable output current(while also allowing PWM or DC voltage dimming) between 350mA - 1050mA, I'll order one of those and those 4 UVA LED's.

Why do not you gain some growing experience first?
UV light can cause damage that can be defeated with nutrient deficits or PH fluctuations and it is important that you recognize the difference. I would do a few grows and if I know how to keep my plants happy without UV I would start using it. You can not put a novice driver in a tank and expect him to drive it perfectly. If it's too much it cause damage but if it's not enough it does nothing. Don't get me wrong, I like to add these wavelength but you should realy improve your grower skills at first and then get use of it.

Planet Tomato said:

I have a plan, first of I want to tell you about my safety features.

I will install a magnetic sensor(don't know the name but those that are often used for home-alarm systems where there are 2 peaces, one magnet and one receiver which senses if the magnet is close or not, perhaps a reed-switch) on my tent so that the microcontroller which is controlling the ON/OFF of the UV LED's.
So the UV LED's will only be allowed to be active when the door to the tent is closed,

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That's standard machine safety guard practice and will work fine.

Planet Tomato said:

This makes me think that paying $81.00 for a 280nm diode is a mistake.
Could you elaborate a little about what you mean by "how they're driven"?
Do they last longer if I reduce the current somewhat?

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Youre exactly right, the more power you run through them the shorter their life. This mainly applies to diodes below about 350nm the higher UVa diodes are fine in my experience.

Planet Tomato said:

Let me ask this, is there any reason to think that it wouldn't/couldn't work out pretty much the same if I exposed my plant to periods of UVA light using all 4 of the LST1-01G01 series?
LST1-01G01-UV01-00, 365nm, 875mW $21.80
LST1-01G01-UV02-00, 385nm, 1015mW $11.48
LST1-01G01-UV03-00, 395nm, 1015mW $11.48
LST1-01G01-UV04-00, 405nm, 930mW $11.48

I am actually leaning towards getting the above mentioned 365nm, 385nm, 395nm and 405nm diode starboards and use that too see if I get any results, the thing is that I am not an experienced grower so I can't tell if it works or not(I'm on my first grow). The UVB LED is so very expensive and what if I would only get 50h or 100h out of it, that would feel like wasted money.

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Give them a try and see how it goes, what i found were peaks in the UV spectrum just like in the PAR spectrum, these are about 395nm and 365nm in the UVa and 280 nm in the UVb.
Before adding diodes remember that you need to get a spread that covers your plants but you need to stick to the ratio of UV to PAR, your plants will be seriously unhappy with too much. You also need the ratio of UVb to UVa.
Don't know if this parts in my head but when playing about trying to get things dialled in it seemed like UVa helped repair damage from UVb to an extentbut again only if you didnt exceed normal ratios.

UVa alone has effects and the diodes seem to last long enough, mines are still going but i spent hundreds on UV diodes trying to figure some of it out and no way im spending more till i think reliability has increased. It was worth it for the info i suppose lol
UVa alone wont give the same results as mixed UV

Planet Tomato said:

I really like this idea, and I will use a RTC clock to determine when and if the LED's should be active, and experiment with duration of activation and number of occurrences each day.

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UV is similar to far red in my experience in as far as its a micromol quotent that needs fulfilled but with UV its a percentage of your daily supplied PAR micromol count and it needs delivered in low doses at high output or low output for longer periods.

Hope that's if some help, its about all I learned from my experiments

Randomblame said:

Why do not you gain some growing experience first?
UV light can cause damage that can be defeated with nutrient deficits or PH fluctuations and it is important that you recognize the difference. I would do a few grows and if I know how to keep my plants happy without UV I would start using it. You can not put a novice driver in a tank and expect him to drive it perfectly. If it's too much it cause damage but if it's not enough it does nothing. Don't get me wrong, I like to add these wavelength but you should realy improve your grower skills at first and then get use of it.

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Fair and just point that i should've mentioned too, it really doesnt take much to lose the effect gained.
I figured if folks are asking they must have their grows dialed in pretty well

agreed. you can grow GREAT weed without supplementation and unless you are growing consistently great weed you risk overcomplicating things and reducing your overall quality and yield.

Hi fellows.
why nobody try to buy a Seoul Viosys UVB diodes.the look so cheaper than rayvio,have good range of spectrums from 275 to 410nm
the uvb 275nm cost 25$ and have a good price drop on qtty
Enjoy and have fun to all RIU.
cannot add the links((((
so here s a part number
CUD7GF1A

Here's the link. Very interesting. And he's right. HUGE price drop over 25+.

http://www.futureelectronics.com/en/Technologies/Product.aspx?ProductID=CUD7GF1ASEOULVIOSYSCOLTD6084036&IM=0

I find it funny that all these years every write up or study attributes THC and resin production based on UV Rays. But we've proven that not to be the case using LED. So it must just be a part of photosynthesis in itself like normal biomass is generated.

Airwalker16 said:

I find it funny that all these years every write up or study attributes THC and resin production based on UV Rays. But we've proven that not to be the case using LED. So it must just be a part of photosynthesis in itself like normal biomass is generated.

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UV stimulates growth as well in my experience.
I did a run with reduced blue and higher uv and found they grew pretty much the same so the blue receptors must use the UV too IMO, i agree that the added effects of UV aren't the be all and end all studys can make them out to be and as previously mentioned the effects are easy enough to lose

Those diodes are fairly priced I'd agree but think about the 275nm. That's UVc territory, im not saying it wont work but there's more than plants to think about.
I've no doubt the 280's i used must have emmited some UVc
Ive played a lot with spectrums, green and yellow too.
I still wont be buying any more UVb leds until prices are better than that tbh

SSR said:

UV stimulates growth as well in my experience.
I did a run with reduced blue and higher uv and found they grew pretty much the same so the blue receptors must use the UV too IMO, i agree that the added effects of UV aren't the be all and end all studys can make them out to be and as previously mentioned the effects are easy enough to lose

Those diodes are fairly priced I'd agree but think about the 275nm. That's UVc territory, im not saying it wont work but there's more than plants to think about.
I've no doubt the 280's i used must have emmited some UVc
Ive played a lot with spectrums, green and yellow too.
I still wont be buying any more UVb leds until prices are better than that tbh

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like Viagera...….growth simulant

Dave455 said:

like Viagera...….growth simulant

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Dunno if its a growth stimulant but im sure the blue receptors are using it