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Project: SEPT
Date:March 2008


SEPT - Super Efficient Photosynthesis. A grow light made from red and blue LEDs being pulsed. This light fits inside a Altoids container and requires less than 1.1W of energy to grow a 6"x6"x6" space. Lights can be chained to grow more plants. Total lumens = 111. Plants need primarily red (680nm) light to grow and a small amount of blue (440nm) light. By pulsing the LEDs at 720Hz or higher the plant can achieve maximum growth with a minimal amount of energy.


LED Details:

I've based my LED project on this paper.

Pulse Frequency720Hz
red LED wavelength (nm)633
red LED mcd3920
red LED view60
red LED lumens3.3
red LED mA50
red LED V2.15
red LED qty30
blue LED wavelength (nm)469
blue LED mcd392
blue LED view120
blue LED lumens1.2
blue LED mA30
blue LED V3.4
blue LED qty10

gmv1pcbbarebonespcb 6.57 1 6.57 17.14
atmega169atmega169pv-8au-nddigi-key 3.81 1 3.81
555-167rj45 jackdigi-key 0.56 2 1.12
cat-5cable per 1'thrift 0.06 2 0.11
475-1304-1-NDblue leddigi-key 0.62 10 6.20
475-1321-1-NDred leddigi-key 0.31 30 9.30
P150ACT-ND150 ohm 0805digi-key 0.02 25 0.60
EG1847-NDpower switchdigi-key 0.85 1 0.85
uln2003adtransistordigi-key 0.32 4 1.28
NJM#7805FA-ND5V Reg. 7805digi-key 0.50 1 0.50
P993-ND1uF decoupledigi-key 0.06 2 0.12
SAM1074-50-NDjtagdigi-key 0.22 1 0.22
A24923-NDrj45 plugdigi-key 0.26 2 0.52 8.00


  1. schematic (pdf)
  2. gerbers (zip)
  3. schematic (gschem format)
  4. pcb (pcb format)
  5. source code(html)
  6. source (tarball)

I have sold out of grow lights. Thank you for your purchases.