Power Arduino Mega ESP85266

Question

Is it possible to Power a Arduino Mega 2560 and a NodeMCU V2 ESP8266 ESP-12E from a single 9V Block?

What would be the best solution?

Can i power the ESP8266 directly via the Arduino Mega 5V output? (3.3V Output seems to weak)
Is a Power Converter like this for the ESP8266 necessary?
Should i use another external Power source for the ESP8266?

Thanks for any Help :)

Majenko · Accepted Answer · 2019-01-31 22:56:43Z

1

Is it possible to Power a Arduino Mega 2560 and a NodeMCU V2 ESP8266 ESP-12E from a single 9V Block?

Yes. Assuming the "block" can provide enough current.

Can i power the ESP8266 directly via the Arduino Mega 5V output? (3.3V Output seems to weak)

No.

Is a Power Converter like this for the ESP8266 necessary?

Yes if you are powering it from more than 3.3V.

Should I use another external Power source for the ESP8266?

Not necessary if the 9V one can provide enough current as I mentioned above.

answered Jan 31 '19 at 22:56

Majenko♦

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Can i power the ESP8266 directly via the Arduino Mega 5V output? (3.3V Output seems to weak) No - why not? I'm not questioning your answer, just wanted a reason why the Mega 5v can't be used to power a nodemcu via the nodemcu's Vin – Jaromanda X Jan 31 '19 at 23:05
The mega can only provide Max 800mA. That has to include what the mega uses, which leaves only just enough for the esp8266. You really need 1A for the nodemcu to work reliably. – Majenko♦ Jan 31 '19 at 23:07
fair enough, I thought the Mega could provide 1A - but that seems to be the spec for an Uno – Jaromanda X Jan 31 '19 at 23:10
It varies from model to model. The actual limit actually is dependant on the incoming voltage and how much heat that generates in the regulator. In practice you can't get more than a few hundred milliamps before it gets hot if you have 9v or more on the input. – Majenko♦ Jan 31 '19 at 23:11
The "1A" is the rating of the regulator. That is only achievable with good heat sinking and minimal difference between input and output voltages. With anything over about 9V half your power (or more) is being converted to heat - and there isn't good heatsinking. So it gets too hot and shuts down. On an Arduino I wouldn't want to draw more than maybe 400mA with >9V on the input. – Majenko♦ Jan 31 '19 at 23:53

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