I am very new to the world of circuit design and would greatly appreciate some feedback on this circuit I made. It is based on an Arduino Pro Mini and its purpose is to illuminate nine 2V, 20mA LEDs as well as twelve SK6812 RGB LEDs. At full brightness, they require 60mA. Since the circuit will be inserted inside a 3D printed scale model, I would like to make sure the components are well protected so they can last a long time.
Here is the schematic of the main circuit. The resistors values of 50Ω and 150Ω are there to limit the current inside the LEDs to 20mA which is the recommended limit per pin on the Arduino (see link above). Also, the 9 LEDs need a total of 180mA, just below the 200mA limit.
Each group named PIXEL_QUADx corresponds to a circuit that is very similar to the one at the end of the SK6812 datasheet. Their schematic is shown below. The 0.1µF capatitors, 470Ω resistor, and 1000µF capacitor (on the schematic above) are added because of the recommendations found on Adafruit's website.
My first question is: is this circuit correct? Other points I am not sure about are:
- Should there be a 470Ω resistor on each PIXEL_QUAD group, or only on the first one?
- Would it be possible to power everything from batteries? USB?
- On the Arduino datasheet, it says the RAW input range is 5-16V, but recommended range is 6-12V. Should I use a 9V supply instead? How would this work?
- 180mA for the LEDs is close to the 200mA output limit of the Arduino. Would it be safer to power the white LEDs directly from the power supply? (This would mean no PWM brightness control)
- Anything else that I missed that needs to be checked?