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BobT
BobT
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You can connect directly to the IO pins. The GPIO pins on the RasPi processor (BCM2835) supply 3.3v @8ma of drive by default but are programmable as far as pull-up, current, slew rate, etc. see http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 for a summary.

Having said that, unless you're adept at programming those pin parameters, you probably want to limit current with a resistor. Assuming your LED needs 1.5 volts @ 5ma, 3.3v - 1.5v = 1.8v drop. R = E/I so R = 1.8/.005 = 360 ohms should be safe.

Solder this resistor to one leg of the LED. One side of the LED/resistor goes to the GPIO pin, the other side goes to ground.

You can connect directly to the IO pins. The GPIO pins on the RasPi processor (BCM2835) supply 3.3v @8ma of drive by default but are programmable as far as pull-up, current, slew rate, etc. see http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 for a summary.

Having said that, unless you're adept at programming those pin parameters, you probably want to limit current with a resistor. Assuming your LED needs 1.5 volts @ 5ma, 3.3v - 1.5v = 1.8v drop. R = E/I so R = 1.8/.005 = 360 ohms should be safe.

You can connect directly to the IO pins. The GPIO pins on the RasPi processor (BCM2835) supply 3.3v @8ma of drive by default but are programmable as far as pull-up, current, slew rate, etc. see http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 for a summary.

Having said that, unless you're adept at programming those pin parameters, you probably want to limit current with a resistor. Assuming your LED needs 1.5 volts @ 5ma, 3.3v - 1.5v = 1.8v drop. R = E/I so R = 1.8/.005 = 360 ohms should be safe.

Solder this resistor to one leg of the LED. One side of the LED/resistor goes to the GPIO pin, the other side goes to ground.

Source Link
BobT
BobT
  • 796
  • 4
  • 6

You can connect directly to the IO pins. The GPIO pins on the RasPi processor (BCM2835) supply 3.3v @8ma of drive by default but are programmable as far as pull-up, current, slew rate, etc. see http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 for a summary.

Having said that, unless you're adept at programming those pin parameters, you probably want to limit current with a resistor. Assuming your LED needs 1.5 volts @ 5ma, 3.3v - 1.5v = 1.8v drop. R = E/I so R = 1.8/.005 = 360 ohms should be safe.