More than one LED per channe
Multiple LEDs can be connected in series, as shown, and the supply
voltage should be at least 2-3V higher than the sum of the forward voltages
of the LEDs.
Multiple LEDs can be connected per channel; they should be connected in
series, as shown above, and the power supply voltage must be at least
1-2V higher that the sum of the forward voltages of the LEDs.
For instance, our blue 3W LEDs have a forward voltage of 3.2V to 3.8V. To
be on the safe side, use the highest voltage in the range. If you want to
connect four of them, you’d need a power supply of ~17V or greater (3.8V +
3.8V + 3.8V + 3.8V = 15.2V; add 2V of “head room”).
Since 17V is greater than the Arduino can tolerate on its input, we have to
provide an external supply for the Arduino as well. This can be the standard
5V USB supply.
It’s perfectly acceptable to mix colors either between channels or on one
channel, so long as all of the LEDs can handle the current (330mA or
660mA, depending on the jumper setting). Just make sure that the power
supply voltage is high enough to handle the sum voltages of the highest
voltage string. There is also no requirement that the three strings of LEDs
have the same forward voltage of LEDs across them; you could have one
white LED on channel 1, two red LEDs on channel 2, and four green LEDs
on channel 3.
Code example
Code for controlling this device is trivial; simply use the analogWrite()
function to adjust the brightness via PWM.
