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Topic: Arduino with Daisy Chained 595 ICs (Read 291 times) previous topic - next topic

ignobilis

May 11, 2014, 02:31 pm Last Edit: May 11, 2014, 02:33 pm by ignobilis Reason: 1
Background:

I am building a simulation of a match stick game as a learning experience. My game needs 9 LEDs, so I have used the ShiftOut example at http://arduino.cc/en/tutorial/ShiftOut to build my circuit, but with only the 9th LED being driven from the second 595 IC (the other 7 pins are unused). I have also followed the advice of posters on the forum and added two 0.1uf caps, on each of the respective Vcc pins of the two ICs.

Problem:

The circuit seems to be well behaved and I can light whichever LEDs I want as necessary. However, the single LED that is the only one being driven by the second IC is noticeably brighter than the other 8.

Question:

I am correct in thinking that the only way to get even brightness on all the LED would be by powering them off a separate circuit with its own power source, and to rather control NPN transistors from the IC pins to switch the LED circuits on and off?

Any advice will be appreciated.

Thanks in advance for any replies.

Ignobilis



spycatcher2k

Or put a resistor between the driver and led to limit the current.
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