Thank you everyone for your replies!
INTP:
What do the lights do? Animate in any way or do they just flash? Do you need to control every single LED?
So you have any 5mm LEDs on hand? Do you think they will be bright enough for your purposes?
You can buy small WS21812 prewired matrices that are very very bright (and you can of course dim them down to whatever you'd like) and you wouldn't have to deal with a bunch of transistors and a whole lot less wiring.
I want to make them just like on the video. I don't have to control every single LED. If you notice on the video, around 8 LEDs are controlled by only 1 pin.. And yes, I have LEDs on hand. I already have a code for animation and brake input but only 2 LEDs for every pin and arduino connected to USB on PC.
Yes, these 5mm LEDs are bright enough for my purpose. I have read WS21812 are not ideal for automotive because they have shorter life and 5mm LED bulbs are what everyone uses on all tail light projects I see..
DVDdoug:
Some people like to use an external voltage regulator, but the Arduino has an on-board regulator and it's rated up to 20V through the barrel jack or Vin. (I have an Arduino in a car powered by '12V' through the barrel jack.)
Arduino's recommended input power is only at 7V - 12V. The car voltage can spike and stay up to 15v. I just want to play it safe that is why I am planing to use a buck converter.. And when you said "external voltage regulator", that is a buck converter, right? Do you think this one would work?
https://shopee.ph/Super-mini-Step-Down-buck-3A-DC-DC-Converter-Power-Module-i.31595899.475167820
DVDdoug:
The LEDs can be powered by 12V, through the MOSFETs & usual current limiting resistors. If you try to power all of those LEDs through a 7805 (or the Arduino's built-in regulator) the regulator will probably overheat.[u]Here is a MOSFET driver circuit[/u]. (You can leave-out the diode, it's for inductive loads like a motor or solenoid.)
Okay, I will try this one.. But, won't my current MOSFET setup work?
DVDdoug:
Don't use a voltage regulator for "signal". Voltage regulators are for power supplies. Use a [u]Voltage Divider[/u] (2 resistors) with an added [u]over-voltage protection diode[/u].
Try it first with just one LED per channel and without the MOSFETs. Then "build-up" the circuit a little at a time.. Add the MOSFET with one LED before adding the others.
Won't the resistors overheat or something? Also, since the voltage fluctuates, how will I be able to calculate the resistance? Should I just calculate it as 12V then let the over-voltage protection diode do it's job?
Daz1712:
Cant see it mentioned but you have run a 5v regulator into the Vin which runs to the input of a 5v onboard regulator.
Run it to the 5vDaz
Ohh, thanks.. On where should I put the inputs?