LED experiments begin

[Mrobert]

Perhaps: LED Grow Light DIY
The guy I am working with tells me this is a very amateurish attempt.

It would be cool to have a small arrays per 2-3 plants in a Wardian case. I think this would be possible by using small prewired boards.

[Korxi]

I've actually done this

I've installed 4 1W highpower LED's and 2 3W highpower LEDs in my terrarium. THese are FAR FAR FAR better than those "normal" 5mm LEDS one 3W led emmits 100lm in an angle of 110 degrees. Comparred to using the normal 5mm LEDs you get a higher output pr. Watt, and it is very much easier to replace one of these than 70 "normal" LEDs

The type called Seoul p4 is really good! And you can get them in several different colors. For now I've tried using a combination of warm and cool white and a "natural white" this gives me wavelengths mostly in the 450nm area and from 600-650nm.

As I've read - these highpower LEDs are the future of LED lighting!

Christian

[Mrobert]

Korxi, Thanks for chiming in with the info. Can you include some pictures?

Progress:
My prototype array is being worked on as we speak. It is being used preengineered circuit boards, either 4X9 (36 diodes) or 5X9 (45 diodes). Not sure about what LEDs I'm going to use...

[Ron-NY]

I also would be interested in pics and knowing how far from the lights that your plants are positioned.

[Mrobert]

Ron- I did some searching on many hydroponic forums. Seems that LEDs are the lighting de jour. I am reserving final judgment on LED-distance-to-plant until when I conduct my own experiments. The hydroponic setups I've seen that are being used to grow "regular" plants seems not much different than setups that use conventional lights. Apparently LEDs are big with the marijuana growers as they don't suck wattage or produce a large thermal signature...just FYI...there is a lot of good information to be gleaned from those law breakers.

[Korxi]

Korxi, Thanks for chiming in with the info. Can you include some pictures?

Progress:
My prototype array is being worked on as we speak. It is being used preengineered circuit boards, either 4X9 (36 diodes) or 5X9 (45 diodes). Not sure about what LEDs I'm going to use...

I'll post pics as soon as possible, I actually think I need more light, but that will have to wait - I'm on a tight student budget

When you say you don't know which kind of LEDs to be used, do you then mean whether it should be highpower or regular 5mm LEDs??
If you do, you should know that highpower LEDs are nothing like 5mm LEDs - they are mounted on an aluminum hexagon and do not have "legs" or anything, they do however need to be mounted on an additional heatsink since they generate some heat. So if you are considering using highpower LEDs a "normal" circuit board will only do little good But you probably know all this

Christian

[Mrobert]

Actually I didn't know that! I've sent a query to my EE-guy. OK, so what bulbs did you select? Any info you can give me on wavelength, model #, or beam pattern is appreciated.

[Korxi]

I've used:
1W LEDs - Luxeon star, 3 warm white and one cool white (it probably should have been the other way around since the plants need more of the "blue" light of around 450nm tech. sheet you can get alle info you need here


3W LEDs - Seoul zled p4, 2 natural white. I found that this color should provide a good basis for phot synthesis with peaks in both 450 nm and aprox 600-650nm Tech. sheet

I just read something today regarding white LEDs, that they are actually phosphorised blue leds that emmit light that for us looks like white light but really isn't and that the plants are not "fooled".. I have no idea whether this is true or not - but if it is, I just wasted alot of money on my setup! I'm hoping it's not, and since the manufacturers can provide spectrums of the light showing peaks as I mentioned before I think I'm good with my setup, but who knows?! In any case blue red or amber colored LEDs could be used to create a perfect spectrum for the plants, however it might not be that pretty in the living room or windowsill...

I'll snap some pics of my setup a little later today.

Christian

Edit: Another really good bet would probably be Luxeon K2 Tech. sheet
I didn't use these since they need a constat current supply of at least 1000mA, and the LED drivers readily availible only go up to 750mA, and this can easily drive the Seoul p4's (they can also handle 1000mA though). If you have some tech wiz on your side you should really look into these - I believe I read somewhere that they can hadle temperatures of up to 125 degrees celcius with out taking damage - which lessens the need for additional heatsinks..
Oh and another thing is - they come in more colors that the seoul p4, but you can see this from the tech sheets

In any case, if you choose to go for highpower LEDs you should also look into collimator lenses, since the LEDs emmit at an angle of around 100-130 degrees, and the FC or lux would be way to low. Something like 5-25 degrees would be prefferable depending on how far above the plants the lights are fixed. I believe that there are companies called Carclo and Kathod that produce them..

[Korxi]

Here's some pics of my setup

I did a pic with and without the LEDs on at the exact same apperture and shutterspeed so you can see the difference under the same conditions.

I also took a pic from below to show you how I set it up. The proffesional lenses are Carclo as I mentioned above, those I had to camuflage with biig bulky silicone pads covered with background material.

The others I made myself by pressing aluminum foil over a pointy thing and applying silicone to the back, while it was still wet I spplied cut up background material. THis was actually the best sollution since you can make the lenses as you want and cut back anything not needed

The LEDs mounted on heatsinks are the 3W Seoul P4. The others are just mounted on some metal that is pushed in to the background - acting like a heatsink aswell.

Christian

[Brutal_Dreamer]

Very cool idea. Thanks for sharing it with us.

Cheers,
BD