I am 95% sure about this, but figured I pose the question anyways. For the Arduino Pro Mini, I can power the Arduino Pro Mini in parallel with series / parallel LEDs? I know the max current on the mini pro is 150mA but the LEDs will be pulling more than that. Just want to confirm the extra current being pulled from the LEDs won’t fry the ardiuno. I plan on using the unregulated VCC PIN on the Arduino for power and will be using the https://www.sparkfun.com/products/12889 wall adapter.
The Arduino pins can only drive a max of 20mA. The Arduino will be damaged if you exceed this limit. Therefore, if the LEDs draw more than that, you will have to use a driver transistor for every pin that is driving LEDs. Since you mentioned that the LEDs would draw more than 150mA, you will need the driver transistors. The wall adapter you cited should be able to power both the Arduino and the LEDs. If the Arduino runs at 5 volts however, then you will need a wall adapter that produces at least 6 volts, so that the Arduino's voltage regulator will work properly. If this is a 3.3 volt Arduino, then you will be OK. If this is a 3.3 volt Arduino and the LEDs are powered by 5 volts, then you absolutely need the driver transistors or the Arduino will be damaged.webmastadj:
I am 95% sure about this, but figured I pose the question anyways. For the Arduino Pro Mini, I can power the Arduino Pro Mini in parallel with series / parallel LEDs? I know the max current on the mini pro is 150mA but the LEDs will be pulling more than that. Just want to confirm the extra current being pulled from the LEDs won’t fry the ardiuno. I plan on using the unregulated VCC PIN on the Arduino for power and will be using the https://www.sparkfun.com/products/12889 wall adapter.
davep238:
The Arduino pins can only drive a max of 20mA. The Arduino will be damaged if you exceed this limit. Therefore, if the LEDs draw more than that, you will have to use a driver transistor for every pin that is driving LEDs. Since you mentioned that the LEDs would draw more than 150mA, you will need the driver transistors. The wall adapter you cited should be able to power both the Arduino and the LEDs. If the Arduino runs at 5 volts however, then you will need a wall adapter that produces at least 6 volts, so that the Arduino’s voltage regulator will work properly. If this is a 3.3 volt Arduino, then you will be OK. If this is a 3.3 volt Arduino and the LEDs are powered by 5 volts, then you absolutely need the driver transistors or the Arduino will be damaged.
Dave, thanks for the reply. I am looking at powering the LEDs separately but wondering if I can run the Arduino off that same power supply in parallel with the LEDs. Will the additional current pull from the LEDs effect the Arduino even if the Arduino is connected parallel with the LEDs? I have attached a basic (very basic) diagram on what I am looking to do. Of course each of the LEDs will have resistors limiting them to 18 mA each for a total for 108. Later more maybe added to the chain.
If you have a 5 volt Arduino, it should be OK to connect your big power supply to the Arduino’s +5V pin. Just don’t have the USB connected at the same time. I’m guessing that you only have 6 LEDs (108mA = 18mA * 6). If that’s so, then you can run each LED to its own pin on the Arduino (with a current limit resistor). I’m assuming that each LED will be individually controlled by the Arduino. However, your diagram shows a single MOSFET which implies that you are controlling all of the LEDs through a single Arduino pin. So, if an Arduino pin must control more than 18 or 20mA, then you need a MOSFET to drive those LEDs.
So, I’m curious, how are the LEDs connected to the Arduino, as a group or individually?
The plan is to have multiple sensors and strips of lights that will be turned off and on via buttons or automatically via the sensors. So even though the diagram only shows one PIN being used, there will be more.