1. To drive Luxeon star LED for use with ronja http://ronja.twibright.com/) or for some other Free space optical link three stacked 74HC245 ICs can be used as shown in the circuit diagram, this can give currents in the orders of 350mA .Important : Do not forget to put an additional heat sink for the LED besides its built in heatsink .There is a star LED with optics available which has beamwidth of 10 degrees and optical efficiency of almost 85% so ranges will be extremely good in case luxeon star with optics is used instead of normal star LED which has very large beamwidth ( 100 degrees approx)
2. The waveforms of the tests carried out at 10 MHz and 1 MHz are shown in the figures .
3. The luxeon Star luminled is much more powerful and bright compared to Superflux LEDs which are not available easily everywhere in the world in small quantities.
3. The luxeon Star luminled is much more powerful and bright compared to Superflux LEDs which are not available easily everywhere in the world in small quantities.
4. If this LED is used with slight modification to the transmitter better ranges can be obtained compared to normal ronja link using superflux LEDs.
5. Figures below show Signal generator output on Channel 1 and Reciever ouput on Channel2 at 1 MHz and 10 MHz respectively
