USB and power supply at the same time?

[espruino-discuss3]

Posted at 2015-10-22 by dbkingsb

Hello,

I want to power a lot of individually addressable LEDs, but also have my espruino hooked up to my computer for coding. Can I do the following setup?

• USB connected to computer
• Espruino ground pin connected to 5V power supply ground
• LED ground connected to 5V power supply ground
• LED 5V connected to 5V power supply ground
• LED data connected to some Espruino SPI pin

[espruino-discuss3]

Posted at 2015-10-22 by DrAzzy

Yup, that's fine.

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Posted at 2015-10-22 by dbkingsb

Awesome, thanks :)

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Posted at 2015-10-22 by @gfwilliams

You might also want to look at what I just posted here: http://forum.espruino.com/conversations/276353/#comment12582618

Sometimes if the LEDs are running off a full 5v, trying to drive them using 3.3v data can be a bit unreliable - a single resistor fixes it pretty well though (in your case I'd pull data up to the Espruino board's 5v).

Just to add, if you also connect the 5v from the power supply to Espruino's 'Bat_In' pin (on the original board you'd need a JST battery connector for that), then Espruino will happily switch over the power source so it can run without a PC.