Monitor Power

[Shepster34]

Hi

Complete brand spank new noob here. Im ok with software and building the bartop but not so much with electronics

Ive sent for my new pi 2 and eagerly awaiting its arrival. It will hopefully be here by the weekend
I want to use the pi 2 to build a small bartop arcade using retropie..

I want to keep it simple so would like to have 1 output wire to the socket and power everything from this.
So i would need power for Pi2 itself, power for the monitor, speakers and led buttons.

From reading around the net i can see some monitors seem to be able to be powered by splitting the 5v 2a that also powers the pi2 (some are 9 inch)

However, i wouldnt mind a 10inch - 12inch led monitor and these all seem to state 12v. (ive seen an ipad 2 lcd with a compatible driver board that would be perfect but again it states pwer is 12v)

Can anyone give me any advice how i can tell if a monitor can be also powered by the 5v power adapter or how i can get more power to the arcade to power them all easily without blowing up the other stuff.

thanks in advance

[W. H. Heydt]

Why not bring 12v to the box and then use a power regulator (the UBEC units have been touted from time to time) to split off a 5v supply for the Pi?

[Shepster34]

Hi

Thanks for replying

Ok so i get a 12v supply, which i can see there are plenty on Amazon, these seem to range from 3a to 5a, which will go from the outlet to the arcade.

I then get a UBEC which will step down the voltage to 5v which i can then use to power the Pi 2.

So can i just wire the input wire of the UBEC, the monitor power, possibly powered speakers and button led's all the the 12v power source by some kind of junction box? I just have to make sure that everything in the junction box is 12v and anything else that is 5v is wired to the output wires of the UBEC. Have i understood correctly?

Do you think im safer getting a 12v 5a power adapter of should i stick to 3a? would the extra amps affect usage if they are overkill?

Thanks

[BMS Doug]

Hi

Thanks for replying

Ok so i get a 12v supply, which i can see there are plenty on Amazon, these seem to range from 3a to 5a, which will go from the outlet to the arcade.

I then get a UBEC which will step down the voltage to 5v which i can then use to power the Pi 2.

So can i just wire the input wire of the UBEC, the monitor power, possibly powered speakers and button led's all the the 12v power source by some kind of junction box? I just have to make sure that everything in the junction box is 12v and anything else that is 5v is wired to the output wires of the UBEC. Have i understood correctly?

Yes, that's it.

Do you think im safer getting a 12v 5a power adapter of should i stick to 3a? would the extra amps affect usage if they are overkill?

Thanks

I'd go for the 5A, having more power available than you intend to use isn't a problem. (it isn't a problem at this scale, drawing <2A from a 30A power adapter may cause problems but drawing 2A from a 5A adapter won't be an issue).

[Shepster34]

great thank you.

As its electronics im going to use decent parts.
Ive seen an Adafruit UBEC on Amazon im going to order so i just need to source a good reliable adapter now.

Can you suggest a good way to join all these together? are junction boxes used or do people generally just solder all the wires together?

[davidcoton]

Use the screwed connection strip commonly known as "choc block". One rated at least 5A, though a larger size may be easier if there are lots of wires. At 12V you don't need covered junction boxes, but everything must be held in place to avoid short circuits across the supply. Don't rely on insulating tape for that! And I wouldn't recommend soldering, because sooner or later you will want to undo and change something.