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Topic: Control 8 seperate RGB superflux LEDs (Read 1 time) previous topic - next topic


According to this blog post: http://bit.ly/wTCTTx or this post: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1270486354
to control 8 RGBs with 1W seperatly i would need:

24x TIP122
8x 1W RGB LEDs
1x constant current supply
hand full of resistors
1x arduino compatible board with at least 24 I/O Ports
and sufficient cooling for the TIP122

Could that work as a head start?
Is it true that i could also use ports without PWM to control the transistors? is this as good (same effect) as the hardware pwm?



I don't know why you say that, it is not a conclusion I get from looking at those threads.

1x constant current supply

In general you need one constant current supply per LED or string of LEDs in series.



until now I see 3 Options to realize 24 constant current supplys with one DC. It would be nice, if you could judge my ideas and give me some input.

1# Use of a LM 317 https://en.wikipedia.org/wiki/LM317 with a adequat resistor (U=R*I) controlled by the arduino
Is around 3€ for each RGB LED
2# Use of a ST Microelectronics 7805 http://octopart.com/l7805cp-stmicroelectronics-526753#technical_specs and a TIP 122 TNP-transistor
Is around 3€ for each RGB LED
3# Use a AMC 7135 http://www.micro-bridge.com/data/add/amc7135.pdf LED Driver with a TIP 122 TNP-transistor
Is around 3€ for each RGB LED

What do you think of those ideas? I would be happy about your feedback.



1) - Yes this would work.
2) - No this is a fixed voltage regulator, it will not work.
3) - While this is a constant current supply it is fixed at 350mA which is about half of what you need isn't it?

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