I'm new to Arduino, and I'm working on a project which uses an RGB LED Strip WS2812B. I'm currently connecting my Raspberry Pi to the Arduino over USB and sending messages over serial. But now I'm trying to add the LED Strip, it seems that they need an external power supply.
From what I've read, I won't be able to communicate with the Pi over serial and power the lights simultaneously.
Is this right? And if so, what is the simplest solution to my problem of connecting to the Pi and powering the lights?
???
From what I've read, I won't be able to communicate with the Pi over serial and power the lights simultaneously.
???
Makes no sense. Draw a figure, miniature schematics. Maybe that tells.
Ok, thanks. What I was trying to say was is it possible to keep the Uno connected to the Pi over USB, and send messages to it over serial? I need it the Uno to do 2 things:
In the video he has the Arduino powered by the external supply, specifically the short red wire from the protoboard going to +5V on the Uno. You don't want two power sources (the USB and the external +5V) simultaneously because they may not be exactly the same voltage which has the potential to damage either the USB or the external power supply.
What you can do is remove the short red wire, leaving the black ground wire, which means the Uno is powered from the RPI USB and the external power supply is powering the light strip only.
Not quite correct. You will certainly not damage the external power supply.
I am not aware of how the USB on the Pi is wired. If - as i suspect - the 5 V on the USB is directly connected to the 5 V supply to the Pi, then there is no problem at all.
The concern is that PCs, and in particular laptops - may under some odd circumstances be damaged if a higher 5 V supply is fed back into the USB port. I cannot deny this could happen and people on the forums in the past have (very rarely) reported such a thing from supposed first hand. I happen to find it generally improbable as almost all common "powered" USB hubs do exactly this, connect the 5 V power supply directly back to the USB input.
In any case, if the UNO (does not apply to Nano) is being powered from the Pi (probably a bad idea for a start), you simply do not need to connect your 5 V LED supply to the "5V" pin.