I am using the Grove Mega Shield : seeedstudio.com/wiki/index.php?t … ega_Shield with my Arduino Mega 2560
I want to use 8 Grove LED Bar Graph at the same time… seeedstudio.com/wiki/Grove_-_LED_Bar
Of course this doesn’t work because the card doesn’t provide enough power. Even with an external power supply of 12V.
What should I do ? Can I change the brightness of the LEDS ? Or I should use a ULN2803 ?