Put relatively simply as it's a simple project i'd like to control around 20ish LEDs from one Arduino. I'm going to make a lamp (with my 3d printer making the frame and stuff). After researching i've found a little bit of conflicting information for doing this. All point to using a shift register ( 74HC595) I have a multiple "power modules" (5v) like the one from the elegoo bundle and a few dc power bricks within the input voltage range. I'm just looking for a visual of wiring ideas for specifically how to wire the arduino, shift register, and external power. I've also seen I should use TPIC6B595 instead how and why? Many thanks just looking for general guidance. Clarification I wish to have multiple different colored LEDs on the lamp sorry for that lack of needed information. Imagine a slowly spinning lamp ( I already have the stepper motor attached to a platform working just need the lighting. As im using a stepper motor im quickly getting pin limited and was looking for a register to assist.
@PaulRB Sorry for not including that I will be using different color LEDs with this "lamp". As such ill probably use a couple shift registers and many LEDs. I'd like to change the color as I wish.
edit end project isn't what im currently looking at. Im mostly looking at the simple step of powering multiple leds from a external power source.
You don't need or want shift registers for that, but an Arduino is useful.
I think you need only 3 PWM outputs from the arduino plus some transistors and resistors.
Let's say you use 7 red + 7 green + 7 blue. With 5V supply, you will need to wire them in parallel, each with its own series resistor (maybe pairs in series for the red LEDs). Each led can draw up to 20mA so 140mA for each colour channel. An ordinary npn transistor like bc337 will be fine. Use 220R resistors to connect the transistor bases to the PWM pins.
To answer this, we need actual information. You need to start making some sense.
What LEDs? What current do they require? You say 20 LEDs. How do you wish to control them? Specifically, do they need to be controlled individually, or in groups. Do they need to be dimmed, or just switched on and off?
This is what I started to learn about. Literally started watching transistor videos before seeing this but you're correct and that will be what im going with. Many thanks!
