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

saland

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?

Thanx
saland

Grumpy_Mike

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

Quote
1x constant current supply

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

saland

Hello,

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.

Saland.

Grumpy_Mike

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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