Hello all, I trying to control 16 LED's using SFE PCF8575c. I was able to test the chip using this example http://www.youtube.com/watch?v=UXPuzbEV_ic&lcor=1&email=comment_reply_received&lc=WXSmUkaibiuXGHBb-mQG2Gdv_r_3ZM5Zym77mm2PVxs&lch=email_reply&feature=email in which the LEDs are turned HIGH/LOW in sequence from LSB to MSB. I wired the 8575c breakout board as shown in the example however the LEDs are all very very dim. I can see them flickering so I know the code and wiring works. I believe the issue is the chip
PCF8575 in source mode can't provide enough current.
and my wiring is in
"sink" mode (5v -> LED -> PCF8575 pin)
. What can I do to provide more current to the LEDs. I read somewhere perhaps a PNP transistor. I also tried putting a 330ohm resistor on each LED pin (i.e 8575 i/o pins) but that did little to help. Any ideas?