I have been making ‘art objects’ that comprise of LED panels (ws2812B) and NEMA 17 stepper motors . I had been using an Arduino uno and the CNC shield. I used two different power sources: 5V for the Arduino & LEDS and 18V 10a for the shield & steppers. As the art works developed, I eventually ran out of memory for the LEDS. So I got an Arduino Mega and a Ramps1.4. I am currently trying to figure out how to power them. I am not using any 3D printer stuff or fans etc. I would be happy to use the same setup of 5V/Arduino and 18V/CNC Ramps/Steppers. BUT reading about how to set them up, the documentation says the Arduino gets powered by 12V power supply going to the Ramps1.4.And they set the MAX at 12V. Other sources(Arduino forum) say the two boards are powered separately. And other sources say the Ramps can handle up to 24V. Can anyone clear this up before I connect power and burn things up? A BIG thanks for any help!
Do you have a Spec sheet or (ideally) a schematic of the board that you have? If the seller doesnt provide one you should still be able to trace it down from the board markings; part number, manufacturer etc.
‘RAMPS1.4’ covers quite a lot of board designs. All with a common ‘form factor’ and MCU (arduino), but stuff like the power power supply circuit may differ.
These boards have a onboard 5V converter to power the MCU and other 5V components from VIN. And most boards will take up to 24V on VIN since this is a very common voltage for 3d printers. But some older/cheaper bords may only be good for up to 12V. The board spec sheet should list the maximum voltage for the main VIN connection.
easytarget.
Thanks for the reply.
It is a bit frustrating but I think the best option is to just get 12V 10a power boxes . Checking around ,12V 10a should be enough for the motors. If so , I am ok. The board is the basic cheap red version
Red is a common color for PCB boards. Provide links to what you bought, and/or high-quality photos of the boards, and there’s a much better chance of getting meaningfully helpful response. 
Lots of these boards can handle 24V.
Hi mcdanlj, Here is a link to a screenshot . With a bit of soldering the board is convertible to 24 v. It would be a good learning experience, but I ordered the 12V box. The arduino uno and CNC shield worked perfectly , just not enough memory for the LED panels .