Powering multiple (6) Arduinos from a single supply

Projects General Guidance
1

Hey guys,

I've a project involving a MEGA2560 and a bunch of slave Unos (will be barebones '328s). Each '328 is just connected to an 8-bit R2R DAC, and then onto to an op-amp buffer. The MEGA controls each '328 over I2C.

Currently they're all sharing ground, but powered independently via USB. I need to power them from a single supply when I build proper boards. I plan to add an ICSP header to each 328 on the final board.

Is it a stupid idea to regulate the 9V DC through the MEGA DC input, then feed the other '328s from the 5V MEGA pin? Perhaps I'd be better off with an external 5V reg then power all devices the same way?

Are there any other factors I should consider?

Thanks

2

IMHO, it's o'k to use on-board regulator. Single 328 consumes only 10-20 mA. Why not build a project with external DAC's? There are SPI 8 channels on a market

3

I'm already doing multi-master SPI via a bunch of 74244s to share SPI dataflash chips between each '328 and the MEGA, so I'm trying to avoid any further complication on the SPI bus.

Thankfully the audio quality of the R2Rs is sufficient for version 1 of this project. Proper DACs would be cool, though; any particular IC you'd recommend?

Thanks for the feedback :slight_smile:

4

I see, if you already have some traffic over SPI, than 6 audio channels, even lo-FI , would be a problem. Other way around is get parallel DAC, have a look at a project I've done, 12 channels 20 kHz audio 10-bits:
http://coolarduino.wordpress.com/2012/08/23/undecima-audio-output-from-arduino/

5

Very impressive. I've had a dig through some of your other posts, definitely going to go back over these and try to learn from them after this project.

DSP fascinates me but I've never really put any time into it.