Powered USB hubs have to be powered, and I am not aware of any that are able to supply the full 500mA from all outlets simultaneously. Most are limited to 100mA or less per outlet.

I did find a 6A, 6-port USB hub, or so it claims to be - like this one here. I would still need a fair amount of them, though!

 

I hadn't seen one that claimed that much power, and would be skeptical until I tested it. Should be worth a closer look, but sometimes specifications get "lost" in the translation. On the other hand, you may not actually need as much power as I "guessed." Why don't you assemble your prototype, power it up, turn everything full blast, and measure the current (and the voltage)? That would eliminate a lot of the guesswork and might substantially decrease the power requirements for the entire exhibit?

 

I'm not familiar with the Vin port on this model. The issues you have to watch out for is reverse voltage applied to the voltage regulator and polarity. I do know that other microprocessor dev. boards have included designed automatically switching alternate power supply input ports. Like the Trinket. Myself, I have used the custom USB cable, but was not satisfied with the solution (too bulky)

 

Thanks so much tracecom, I'll definitely give this option a try asap and report back when I've tested. Visiting the car park this week too, so I will be bringing a prototype with me.



Ian, this is a really interesting option that I didn't know existed! Do you mean something like this? Or is it better to find a non-switching supply? More like this although not sure I trust alibaba....
!

A surplus PC PSU might even be free, especially since you want it to be an older type. A local PC repair shop could probably sell you a second hand one for not much more than scrap value.

 

I hadn't seen one that claimed that much power, and would be skeptical until I tested it. Should be worth a closer look, but sometimes specifications get "lost" in the translation. On the other hand, you may not actually need as much power as I "guessed." Why don't you assemble your prototype, power it up, turn everything full blast, and measure the current (and the voltage)? That would eliminate a lot of the guesswork and might substantially decrease the power requirements for the entire exhibit?

Thank you for the heads up, I am also quite skeptical about the max amps per port on those things (reviews seem to vary on the websites I've found supplying them)

I have assembled my prototype however a funny thing happened when I plugged in a 5v 2.0a plug to the VIN and GND of the Arduino. The speaker can be powered by the Arduino! (well, through the mp3 player's left to right speaker pins). I detached the LiPo battery and USB (that must've been charging it) and the sound still seems fine. Does this seem OK to bet on, because it would be great if I could power 1 device via 1 plug or even less...

I measured the amps and it seems like the max is around 900mA (it was 0.89 when I had my multimeter on '20m' (if this seems right?)) I also had another general question - when I was measuring the amps with my multimeter, the circuit seemed somewhat disrupted, as the lights/speaker kept turning on and off every half second or so. It would be interesting to know why this happened!

I'm not familiar with the Vin port on this model. The issues you have to watch out for is reverse voltage applied to the voltage regulator and polarity. I do know that other microprocessor dev. boards have included designed automatically switching alternate power supply input ports. Like the Trinket. Myself, I have used the custom USB cable, but was not satisfied with the solution (too bulky)

Thanks very much for this, I am going to research some more as results debating the Nano seem to be varied. At the moment VIN seems to be holding up nicely - do you think if it works consistently for, say, 9 hours, I will be OK for longer? Cheers

A surplus PC PSU might even be free, especially since you want it to be an older type. A local PC repair shop could probably sell you a second hand one for not much more than scrap value.

Going to try and look into this tomorrow! It sounds like a fun option. Dangerous... but fun

 

Thank you for the heads up, I am also quite skeptical about the max amps per port on those things (reviews seem to vary on the websites I've found supplying them)

I have assembled my prototype however a funny thing happened when I plugged in a 5v 2.0a plug to the VIN and GND of the Arduino. The speaker can be powered by the Arduino! (well, through the mp3 player's left to right speaker pins). I detached the LiPo battery and USB (that must've been charging it) and the sound still seems fine. Does this seem OK to bet on, because it would be great if I could power 1 device via 1 plug or even less...

I measured the amps and it seems like the max is around 900mA (it was 0.89 when I had my multimeter on '20m' (if this seems right?)) I also had another general question - when I was measuring the amps with my multimeter, the circuit seemed somewhat disrupted, as the lights/speaker kept turning on and off every half second or so. It would be interesting to know why this happened!




Thanks very much for this, I am going to research some more as results debating the Nano seem to be varied. At the moment VIN seems to be holding up nicely - do you think if it works consistently for, say, 9 hours, I will be OK for longer? Cheers



Going to try and look into this tomorrow! It sounds like a fun option. Dangerous... but fun

"Dangerous"?! - a PC PSU is all earthed and shielded, only low voltages out.

The possible risk I can see is; if you use an ATX PSU, you may have to put a dummy load on the 3.3V output to make the PSU regulate properly - there then comes the issue of dissipating the wasted heat safely.

For dead easy, I usually use a 50/55W H4 bulb as a dummy load, but they radiate heat and can scorch anything they're left close to.

You can get power resistors potted into a hollow aluminium extrusion with lugs for bolting to a heatsink - A few AT/ATX PSUs have overvoltage sensing on the +12V output, a cooling fan on there would stop the voltage creeping up with no load.

 

"Dangerous"?! - a PC PSU is all earthed and shielded, only low voltages out.

The possible risk I can see is; if you use an ATX PSU, you may have to put a dummy load on the 3.3V output to make the PSU regulate properly - there then comes the issue of dissipating the wasted heat safely.

For dead easy, I usually use a 50/55W H4 bulb as a dummy load, but they radiate heat and can scorch anything they're left close to.

You can get power resistors potted into a hollow aluminium extrusion with lugs for bolting to a heatsink - A few AT/ATX PSUs have overvoltage sensing on the +12V output, a cooling fan on there would stop the voltage creeping up with no load.

I think I am just over-cautious because I'm not too knowledgable about this stuff quite yet! Better to be safe than sorry right? But that's good to know!

Maybe I could find a cooling fan for the 3.3v load? I will keep you posted when I source an ATX PSU (if that's ok with you). It's a really nifty idea that I wouldn't have ever dreamed up if I didn't come here so yeah, thank you!