RGB LED scematic from www.adafruit.com (RGB LED weatherproof flexi-strip 30 LED)

Hey!

I found this tutorial at Usage | RGB LED Strips | Adafruit Learning System. I see that there is a pin on the arduino board in the figure named “9V.” On my Arduino Leonardo board, there is no such pin; rather, it is called “Vin.”

First, why does the figure apparently only have voltage coming from the Arduino board at only 9 volts to the pin on the RGB LED strip that requires 12V or above?

Second, since my Arduino Leonardo does NOT have a 9V pin—“Vin” is in the same place as the 9V pin in the picture—is it acceptable for me to connect the wire running from the 12V+ pin on the LED strip to the “Vin” pin on my Arduino Leonardo? If so, how many volts and amps can the “Vin” pin safely handle?

If I were to attach a power source to the “Vin” pin, could my board safely operate with an input from a 12V 2800mAh battery?

Thanks for considering my questions.

B_O_T

P.S. The picture from the Adafruit tutorial is attached.

LEDstrips.gif

I see that there is a pin on the arduino board in the figure named "9V."

It is only on that diagram it is not on any Arduino board. I think it is an indication of what voltage you need to apply to this pin.

The words in the tutorial say:-

Connect a 9-12V power supply to the Arduino so that Vin supplies the high voltage to the LED strip.

is it acceptable for me to connect the wire running from the 12V+ pin on the LED strip to the "Vin" pin on my Arduino Leonardo?

Yes but you also need to connect that wire to a 12V power supply.

If I were to attach a power source to the "Vin" pin, could my board safely operate with an input from a 12V 2800mAh battery?

Yes. the 2800mAh only gives you and indication of how long the battery will last under ideal an mainly secrete discharge rate. This figure is manipulated by manufacturer so that it is the biggest it can be for that battery. In practice you will only get about 80% of this value.

Thanks Grumpy_Mike! That was extremely helpful! :smiley: I really appreciate your input! Thanks for your quick response :slight_smile:

One more question. Is the "Vin" pin capable of being a source voltage, or is it strictly an input pin?

Thanks!

B_O_T

No Vin is bothe an input and output. You can uses it as an input like described here, but you can also use it as an output if you put the power into the power jack. However when you do that the current you can draw from the Vin pin is less than an amp because there is a diode between the two connections that can only carry less than 1A.

If you put ‘power’ into the PWR jack, the Vin pin will have ‘power’ - .7v on it.

The .7v is from a diode which is rated at ~ 1 amp.

Thanks man! That is SUPER helpful :D I appreciate your communication! :)

B_O_T