Node external power

[ferpando]

Hi,
I have the nodes working fine when powered through USB, but when I use a 7v external power supply attached to RAW pin on the pro mini it stops working.
I'm I doing something wrong?

Radio seems to work because the led blinks when I send a command, but the 5v pin reads only a bit over 3v.

[hek]

Speculation: The power supply is probably giving some bad power making radio unusable. Try another powersupply or remove ripple (capacitors etc).

[ferpando]

@hek
I'm using a power supply which is 7v and I guess is regulated.
If I use the raw pin for this, is it wrong?
Sorry for my absolute ignorance but the most I google about this the less clear it is.

That power supply has different selectable values.
If I choose 4.5v and use the VCC pin it works.

[wmylionel]

Your pro mini is a 3.3V version or 5V version. If your VCC pin measures a bit over 3V, looks like you are having a 3.3V version.

[ferpando]

@wmylionel
It is a 5v version. That's what I don't understand.

[BulldogLowell]

@ferpando

it is a 7V power supply but feeding how many mA?

[ferpando]

@BulldogLowell
the power supply is 1.5A. It is one of those electronic ones (like the iphone chafer) without a big transformer

[BulldogLowell]

@ferpando said:

@BulldogLowell
the power supply is 1.5A. It is one of those electronic ones (like the iphone chafer) without a big transformer

sorry for all the questions, it may be easier to see a schematic of the connections or a photo.

you are stepping down the power from the 5V pin to 3.3V to power the radio, yes?

[wmylionel]

You may want to disconnect everything and just leave the power supply and arduino, then measure the RAW pin and VCC pin, RAW should be anything above 5V, VCC should read 5V for the 5V version and 3.3V for the 3.3V version. Any other readings on VCC suggest that your regulator on the arduino is faulty.