Power to Yun - Can I split a 12V 5A to only send 5v to yun?

Other Hardware General Electronics
1

Hey,

I read that the Arduino Yun can only be powered with 5V DC. I want to use a 12V 5A power supply for my project b/c I need to run a strip of LEDs with it. Is there a way to split the volts going to the yun via a breadboard?

Any help would be appreciated!

2

Quick and wasteful way would be a 7805 to step the 12 to 5, but better is to use something like this. EDIT... but look at how much current you need too. Also that 2120 is adjustable which is why I bought it- have a dig around at Pololu.

3

Thanks for the response, JimboZA. I'm trying to cut down on the production costs of a product I'm trying to make and I'm not sure if I can add another $10 to the project. What do you mean by " a 7805"?

I stumbled upon this last night: Programming & Web Design Articles - dummies

Is this resistor method very inefficient?

Thanks for the help!

4

The 7805 is a liner voltage regulator chip and is designed. To do exactly what you want.
Just using resistors will not work at all because the Yun like all processors does not take a constant current. Any changes in the current will change the voltage out of a resistive dividor.

5

Is there a formula to better understand how changes in current will change voltage out of a resistor voltage splitter?

So as the YUN requests more or less amps, this will affect the volts going into the YUN? Is that right?

Thanks for the help, Grumpy_Mike.

6

mostachetti,

Just get the 7805
Intelligent Power and Sensing Technologies | onsemi?
It's not "$10" - all of what you need is less than $2.

7

mjmostachetti:
Is there a formula to better understand how changes in current will change voltage out of a resistor voltage splitter?

Yes it is just ohms law.
As a rule of thumb you should have ten to twenty times the current going through the two resistors in the potential divider as you are taking out as a load across the bottom resistor to reduce the variations, but the more current you waste the better.

But you must not power an active device like a processor from a resistive divider period.

8

To calculate the response of a resistive divider under load you
have to know the resistance of the load - or the limits that this
resistance varies between. Except for micro-power applications
(micro watts of dissipation) a resistive divider is hopeless for
voltage regulation as you lose vastly more power in the divider
than the load.

There are 10,000's of ICs and modules on the market to do voltage
regulation, either linear or switching. Switching regulators (aka
DC-DC converters) are more efficient.