I want to light up an LED strip via an Arduino (ESP8266)
The Arduino’s GPIO has a maximum output of 12mA. It is not enough to power a 5m length LED strip.
An obvious solution is to use a transistor to increase the current. I’ve followed an internet tutorial that used a TIP31 transistores, but my lights were too dim. The solution provided on this answer (RGB LED strip is too dim) is to halve the resistance to 200ohms and even that may not be enough because the current needed is about 2A per channel (6A total). They pointed to me that I could use a Darlington pair to increase even more the current and I’ve decided to try it out but before I could try someone said that it could burn my LEDs.
I can’t replace this LED strip in less than 3 weeks (shipping to my city is hell) and I would like to do it safely.
So um trying to figure out which resistor and which transistor I should use.
Some formulas I already know:
- amps needed per channel: (#LEDS / 3) * 20mA => 2A
- watts needed: V * I => 12V * (#LEDS / 3) * 20mA => 24W * 3 => 72W => 90W to be safe
So I’ve decided to learn how to choose a transistor and a resistance, I’ve found this datasheet for the TIP31 but I can’t decode its math.
Can someone help me with that?