It's been a while since I posted in here but I come bearing a few concerns. I'm on my latest project and I need to gather some opinions, I have a layout and network planned but I request advice please.
Background:
A restaurant wants me to take all of their old jukeboxes and gut them completely and install all digital components.
My plan to save money and to save space was to have an arduino nano with two port expanders connected to 25 various LED's, a coin acceptor, three 2x2 button pads, MAX232 (for the coin acceptor) and then lastly an ethernet shield. (all in each jukebox)
I was going to have each jukebox have a run down to a 8 port power over ethernet 12v router and send power to the boxes through means of that. My concern however is that, If i have one 12v PoE cable in each jukebox, would it be able to continuously support the 12v for the coin acceptor, and the power required to run the arduino and the 25 LED's? I know I can just use a few resistors and convert the power to 5v but i didnt know if having the arduino and led's as well as the coin acceptor would draw too much power.
If you were going to use the ethernet shields "with PoE", you should be aware that they want "real" PoE (48V, with negotiation) rather than one of the hacks that just sends DC over the spare wires.
westfw:
If you were going to use the ethernet shields "with PoE", you should be aware that they want "real" PoE (48V, with negotiation) rather than one of the hacks that just sends DC over the spare wires.
I wasnt going to use an ethernet shield "for" PoE I was going to use one of these and a 12vdc end splitter and have one end going to the breadboard with resistors to bring it down to 5v and the other side of the splitter going to the coin acceptor. but i didnt know if that would take up too much power and bring down the current
MichaelQuick:
and have one end going to the breadboard with resistors to bring it down to 5v
Ears prick up.
Care to explain that?
cant exactly remember where, i think it was on hackaday, but there was once a post i read that had a series of resistors to bring a 12v input down to a 5v output
MichaelQuick:
cant exactly remember where, I think it was on hackaday, but there was once a post I read that had a series of resistors to bring a 12v input down to a 5v output
Yeah, well, no!
You absolutely want the 5V to be regulated which lets out resistors on one score to start with. As if you do want to use PoE in this fashion, the efficiency becomes critically important as you do not want to require any more current than absolutely necessary (particularly through the connectors), so a switchmode regulator would be in order.
cant exactly remember where, i think it was on hackaday, but there was once a post i read that had a series of resistors to bring a 12v input down to a 5v output
That was probably a voltage divider setup. You could run 12v on spare ethernet cable wires and use a voltage regulator at the ethernet shield to get 5v.