Using LEDs for a project

LEDBE
C

Chingyul

Newly Enlightened
Joined
Apr 6, 2001
Messages
140
Location
Alberta, Canada
Hello all,
Just a couple questions. I'm doing a bio project on light intensity.
Anyways, initially we thought of doing the effect of UV light intensity on photosynthesis, but I just found out that we can't use our school's UV lamp as it can only be left on only for a short amount of time. I was thinking of using a UV led, and i'm wondering where i pick on up in town, as in a walk in store.
Also, if that does not work, i'm thinking of just doing regular light intensity and use a blue LED from a fake photon i have. Anyways, i'm planning on hooking it directly to a battery. However, i'm not sure how much voltage i can put though it. I know that initially it ran on 2 3V batteries. How high can i safely go, voltage wise? Last thing. The light will probably be on for about 24hrs, so what sort of batteries would we need?

Sorry for the long post.
Thanks
Dan
 
No problem, you can get 390nm LEDs for about $2 Each, even lower in quan - I have 100 KingBright 390nm LEDs that I could sell you a couple if you are interested

You could easily make up a bank of them that will draw very little power, and can be left on without fear of damage

My sister is a Botanist, and she says that NASA did some studies and found out Plants "Like" RED LEDs the most
 
Dan---What do you expect to happen if you feed UV to the plants? Mutations?

It would seem to me that chlorophyll is optimized for 550nm, the peak of sunlight. I am NOT a botanist, nor do I play one on TV.---Marc
 
Accually, i'm not quite sure.
The main investigation would be to see the relationship between UV light intensity and photosynthesis rate. I do think it would be the same as light, but just to add that extra little bit, i decide to try UV and see.
Also, i'm thinking that i'm gonna see if high UV light exposure will have an effect on photosynthesis.

This is for an IB GroupIV project. It's pretty much 3 different groups from the 3 sciences (phy, chem, bio) each do a lab with a central theme. The other ppl decided to do light intensity, and this was the best i could think of.
bluesigh.gif
 
How many UV LEDs would you need ?

If you wanted to run them off a conv. power source, say 12v - you could run 3 in each string with a dropping resistor - and it would take 20ma (0.020 amp) per leg, hardly any current at all
 
blue spectrum will add to vegetative growth. red will add to flowering. I think the key to this is looking up 'phytochromes' or something like that. Been a long time.

I would be surprised if red LEDs stimulate more growth than other colors.

FWIW, I don't think green (@ 530nm?) would have much an effect at all, if any (chlorophyll being green should reflect this, not absorb).

Good luck, I'm very interested in how the experiemnt turns out. Volumes could be written (and probably have been) about plant response to narrow wavelengths within the visible spectrum. Dealing with UV might be tricky, but interesting.
 
I thought I remember seeing an article from NASA that did research on the idea of growing plants in space using LEDs, and they said RED was the best color

My sister is a Botanist, and she said the same thing; it would be very interesting to try running a experiment with the same type of plant, in the same temp under the different types of LEDs

I would be willing to sell you some 395nm 5mm LEDs for $2/each if you desire; and help you design up a array - I think 16 should be enough for a small plant
 
Interesting. Did she say what the mechanism involved was? I did a remedial experiement in my plant phys class that involved growing grasses under incandescent lights with blue, red, green and clear (control) filters. Blue and clear were very similar, red was next with green below that.

Of course the grasses are nonflowering plants, perhaps that accounts for some of that? I guess NASA would be interested in fruit bearing ones, however, nutritionally speaking. I was thinking of this from an oxygen producing standpoint (more vegetative surface area).

From my class three, four years ago for my bio degree, I remember that there are substances called phytochromes that break down in the presence of a certain wavelength and that these substances work as chemical regulators, that is, if the concentration of the broken-down substance is greater (lol too much Guiness!) flowering will induce.

Also very important to this is the light and dark cycles... the amount of darkness allows the phytochromes to build back up, if you interrupt this cycle, no flowering will occur.

If you could ask your sister more about this, that would be cool. I'm very interested... if red light produces more vegetative growth than blue, I would really like to know the mechanism behind this.

THANKS!

cheers
 
I am not sure if she had first-hand experience, or was just reviewing the articles by NASA

I think it would be great, if someone just did the simple test of having 5-6 plants each with a different bank of LEDs

If I was assured personally by a school
I would loan them some very expensive high power Luxeon panels (Red, Green, Blue)
 
Actually, when you go to school for stuff like this, it's relatively easy to get grants for equipment, etc. If your research parallels that of a professor, it makes it even easier. I for my undergraduate research I looked at ecosystems. For a Masters I would love to focus on plant biology (they dropped the botany designation here) and LEDs in conjunction with hydroponics. As we know there are many benefits to LEDs and hydroponic technology that NASA could use. Maybe even LEDs and water circulation powered by solar energy?

Good stuff. This site helped revive my interest in this.
 
If I remember right, the NASA project used 680,
730 and 880 nM (red, near IR and IR). The 880s
are common, but the 680s and 730s must be special order items. I could be getting these confused with their LEPT wound healing project, which was a spin-off from their plant-growing-in-space project.

/ed brown on terra firma
 
You must log in or register to reply here.

Latest posts

Top