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The VolksLED - The People's DIY Fixture

rives

rives

Inveterate Tinkerer
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I used single channel - there are actually 4 leds mounted on the chip, and the 4-channel version allows you to control them independently. I don't know if the prices that you quoted are for leds pre-mounted on MCPCBs, but Mouser has the mounted ones for those prices.
 
hempfield

hempfield

Organic LED Grower
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repuk said:
Re-reading that I just realized an "automatic" temp regulator circuit could be used also for "auto" dimming, more as a measure of LED protection/maximum life/brightness, dunno about its real usefulness with real HML usage.

Not really sure, but I think just swapping the NTC here for an PTC could do:

Just put the driver dimming inputs where the output to the fan goes:

[URL=http://www.heatsink-guide.com/control.gif]View Image[/url].

This way the PTC resistor that acts as a sensor could go to an strategical place in the heatsink, then set the pot so that under normal working environment it doesn't dim the LEDs. If temperature of the heatsink raises, so will do the PTC, increasing it's resistance and lowering the ouput voltage thus dimming the LEDs.

I have used this to control DC fans while putting the NTCs at canopy levels, and it's a fairly sensitive device.
Click to expand...

Did you had the opportunity to test this on LEDs ? It seems a simple and easy way to control the temperature of the LED. But I think the NTC must be placed closed to one LED chip to overcome the thermal inertia. It would be interesting to see how fast reacts this circuit (it's obvious that we will see some climbing and dropping on the temperature and current )

For the other enthusiasts that want to use this simple circuit, we must tell them that the NTC is the component that cause the MOSFET transistor to open when the temperature goes up and the 10KOhm resistance is the one that close the MOSFET (allowing the voltage to drop under the threshold value on the MOSFET gate).

But this circuit needs some calibration and it might keep the LED(s) on a low current, reducing the light intensity.
 
repuk

repuk

Altruistic Hazeist
Veteran
hempfield said:
Did you had the opportunity to test this on LEDs ? It seems a simple and easy way to control the temperature of the LED. But I think the NTC must be placed closed to one LED chip to overcome the thermal inertia. It would be interesting to see how fast reacts this circuit (it's obvious that we will see some climbing and dropping on the temperature and current )

For the other enthusiasts that want to use this simple circuit, we must tell them that the NTC is the component that cause the MOSFET transistor to open when the temperature goes up and the 10KOhm resistance is the one that close the MOSFET (allowing the voltage to drop under the threshold value on the MOSFET gate).

But this circuit needs some calibration and it might keep the LED(s) on a low current, reducing the light intensity.
Click to expand...

It needs calibration of course, guess I'd be reading DC amp draw, measure the temp with a thermometer to check is in an acceptable value, put the NTC close to a star PCB, let it settle for a while, then use the potentiometer until I get the DC amps I want for that temp.

If temps rise the circuit reacts pretty fast, try it with a fan and a NTC at canopy level, then pinch the NTC between your fingers, the fan will react almost instantly.
 
R

RainerRocks

Member
rives said:
I think that, for cost effectiveness, it is hard to beat combining different types of light to achieve the mix that you want. If you can handle the heat and balance the relative penetrations, there are some interesting options. I am currently setting up a new area that will use (3) of the 315w Philips CDM-T lamps. I found a killer deal on the 3100K versions, and they hit 120 Lm/watt! I'm interested to get a couple of runs on them and then possibly supplement them with some long, bar-style 660nm LEDs.

There is a vendor in the states that is building a "revolutionary" ballast for these lamps that is supposed to deliver a usable lamp life of 50,000 hours, with 95% lumen maintenance at 20,000 hours. Their target market is LED street lighting - with that kind of lamp life, they are directly competitive from a re-lamping standpoint. There is some really interesting stuff going on!

http://gel-usa.com/pdf/CeramaTek_315w.pdf
Click to expand...

May I ask what the killer diller biller willer deal was that you got
for the 315w Philips CDM-T lamps and where from ?

Thanks
 
rives

rives

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RainerRocks said:
May I ask what the killer diller biller willer deal was that you got
for the 315w Philips CDM-T lamps and where from ?

Thanks
Click to expand...


I picked up a case of the 930's on eBay for about 20% of retail cost.
 
G

Goldy

Member
beautiful job there Rives..looks pro. Have been lurking about the LED forums for a bit now and wow! you guys are true pioneers..cant say how great it is to be a part of the forum and learn from you all. :thank you:

P.S. waiting for you to start taking orders lol:biggrin:
 
rives

rives

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Thanks Goldy! I'm in the midst of using the same concept, scaled down a bit (6" long) to build a couple of lights to augment the Volks and cover a bit more real estate. I'm going to be using the Luxeon K series as a test, and perhaps eventually change out the PL-L lamps in my Hybrid fixture with them if they test out well.

*edit* Strange, I was just looking back through the earlier posts and saw that the pictures of the plants vegging under the fixture were missing. They are now added back.
 
G

Goldy

Member
rives said:
Thanks Goldy! I'm in the midst of using the same concept, scaled down a bit (6" long) to build a couple of lights to augment the Volks and cover a bit more real estate. I'm going to be using the Luxeon K series as a test, and perhaps eventually change out the PL-L lamps in my Hybrid fixture with them if they test out well.

*edit* Strange, I was just looking back through the earlier posts and saw that the pictures of the plants vegging under the fixture were missing. They are now added back.
Click to expand...

lol i had wondered what people where on about talking about the screen :laughing: they sure look happy under it

Ill be following your techniques and insight later this year..gonna make me a couple arrays to fit side by side in a dr120..should be sweeet:biggrin:

have full faith that these DIY jobs will be making HID completely obsolete in no time at all.
 
420empire

420empire

Well-known member
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Nice Rives. What would you think about the combu of:
- hyper red and deep blue
- golden dragon plus
- oslon ssl

?? :)
 
rives

rives

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There is "hyper red" in the mix on this light. All that you suggest work well, but are beyond the range of what I wanted to accomplish with this fixture. I wanted to test high-wattage whites for vegging, as well as develop an easily-built enclosure.

I'm not sure how useful the oslon ssl chips are for our application. The two dispersion angles that they have chosen are too far apart, I think. An 80-degree lens concentrates the light too tightly, and a 150-degree lens is too wide.
 
B

BrnCow

Has anyone built a strip of LEDs around three sides of a tent - maybe slanted up and staggered LEDs ? I want to know if hat would make the popcorn buds grow to a decent size and weight...
 
rives

rives

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I haven't seen anything like that. KNNA was talking about doing it, as well a sticking leds inside the canopy of the plant, but he hasn't been around for a while. I think that it would be difficult to hit them with much power because of the problems with heat extraction, but maybe they wouldn't need to be powered too heavily since they would be in such close proximity to the bud sites.
 
rives

rives

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I think that any of the products from quality manufacturers that are within the PAR range of plants can work well. Choosing which ones to use is more a function of the design parameters of the fixture than any other factor.
 
R

RainerRocks

Member
BrnCow said:
Has anyone built a strip of LEDs around three sides of a tent - maybe slanted up and staggered LEDs ? I want to know if hat would make the popcorn buds grow to a decent size and weight...
Click to expand...

There's a guy on another forum who has pics up of LED strips around his tent.

I would post the link but not sure if it's allowed to post links from other grow forums.

Can I post link ?
 
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