I’m working on a project that involves 25 individually powered Arduino Nanos with mp3 playing capabilities, each hooked up to a 3W speaker. The devices need 5 volts and around 1.5 amps to run correctly.

Unfortunately the space I need to install the 25 devices has a limited power supply (only two 230v EU sockets), and I need some advice on how I will go about supplying 5 volts and 30-ish amps to the Arduinos, either individually via 25 separate plugs or together somehow.

Any help much appreciated.


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    \$\begingroup\$ 5V @ 30 amps = 150 watts, easily supplied by your mains outlet. Either get power strips to use individual 5V power supplies for each set or get a few higher amperage supplies connected to multiple sets. \$\endgroup\$ – DoxyLover Sep 10 '15 at 21:03
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    \$\begingroup\$ A 5V 40A supply shouldn't be too hard to find. Many gaming PC PSUs come close (with a lot of 12V rails you don't need) : 2 of these might do, just search for the usual hacks to make them switch on... \$\endgroup\$ – Brian Drummond Sep 10 '15 at 21:07
  • \$\begingroup\$ @BrianDrummond: Indeed. Found in 30s uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/… Op: you need to shop around a bit, but for the specs you want there are undoubtedly numerous off-the-shelf PSUs. \$\endgroup\$ – Fizz Sep 10 '15 at 23:04

I would personally cluster them into five groups of five Arduinos each, with one power supply (5V 8A) per cluster. If you power them all from a single supply, any time the power draw on several experiences a coincident peak, the power to all of them will drop momentarily and you may see CPU dropouts, even with very large busbars carrying power to the Arduinos. In addition, if you lose a power supply (all the magic smoke drains out), I'd personally rather lose the functionality of five of the Arduinos than all of them, and I'd rather replace a failed 8A power supply than a failed 40A one.

  • \$\begingroup\$ I don't think these 3W setups are going to create much of a voltage droop. They ain't motors or power hungry inductive sources. \$\endgroup\$ – Passerby Sep 11 '15 at 2:25
  • \$\begingroup\$ You might be surprised, since full load on each is actually nearly 8W including digital. \$\endgroup\$ – TDHofstetter Sep 11 '15 at 3:19
  • \$\begingroup\$ I'm surprised by that too. The Arduino and a mp3 board taking 1 Amp / 5 watts? That seems unlikely. \$\endgroup\$ – Passerby Sep 11 '15 at 3:55

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