diy spectrometer, no cost to build, post your lighting charts!

http://spectralworkbench.org gives you all the info needed to make an accurate spectrometer from black paper or plastic and an old cd/dvd disc. comes with all software, calibration by cfl mercury bands. seriously takes less than an hour and no money as the device can tape to the camera on your phone, or if you have an old webcam you can make a permanent instrument. i just made one and tested against 2 laser sources and its spot on.

build one and post your spectrums on this thread, with as much info as you can give, especially readings taken from cheap ebay cob leds. help design a dirt cheap open source community light that totally blows away the commercial units £/par

mine below shows a classic 90w ufo, a 100w diy bar of 660nm premium leds, cheap £3 100w ebay cobs, and 2x red/blue 5m @£7 led sticky strip sidelight.

Nice, will be testing mine soon and will post results...

here are my new ones for grow period. consisting of 2 100w white cobs, 1 100w red phosphor, 1 100w blue 450nm, a 660nm 10x10w bar, and a blue 435nm 10x10w bar. all the led cobs were cheap as chips (pun) except the 660nm reds which were premium stuff. now thats a real full spectrum! no gaps and plenty of power where it is most needed. in flower i replace most of the blues and whites with red phosphor cobs that are blue driven (see thumbnail below 'red cob') you can see the great peaks they accidentally left in these cheap £4 cobs.

heres a few of the lights that i built. prototypes at the moment but getting better each time. the cooling system on the long bars is rather complex and involves a fair bit of fiddly metalwork as the heatsinking is all done inside then ducted to the driver module.
all the units are running at 100% power so giving off a lot of heat. next batch will use a modified driver that automatically cuts back the power if they get too hot, something that is cheaper and more effective than constant current drivers. talking as cheap as 8p per watt to build as long as you have a good 12volt supply handy. i run 600w of lights off an old server power supply. these pump out 12v at up to 100 amps and you can grab from ebay for less than a tenner they are less than half the size of a traditional ballast. i get lots of heatsinks from scrap computers on freecycle, the scrapyard and dump. led is officially cheaper than any other light source now, as long as you can solder a few wires on yourself and operate a drill and screwdriver without hurting yourself and others.
for easy setup for a few dollars more you can get a 60v 100a power monitor meant for rc cars. this reads out voltage, amps, watts etc so you dont need to calculate anything.
600w is possible for £60 including power supply, cables, leds, high tech digital readout display. add another tenner for your diy spectrum analyser and a free light meter app for your phone. similar system to buy (in a pretty box with a chinglish manual of how to put a plug in the wall) comes in at way over a grand when you are talking real watts and par. you also get to fine tune the spectrum you want through the whole cycle.
i dont care what the big companies say, if they are from uk or usa or china, all the led stuff you buy comes from china 99% epistar.

Nice, getting ready to build my first one....

the printable version is very good