Bluetooth supply voltage

[amitaiwe]

Hi,
I'm trying to wire up a BT module RN42SM.
I have a battery of 9V and the recommended vin is 3.3v.
I tried using a Voltage divider and it turned out that the BT has a very
high resistance and for various values of resistor the voltage input to
the BT was epx. 1.5V.
only when I connected directly the 9V the BT turned on (led)
and became hot very quickly..
Is there a way of using the battery to connect to the BT without
ruining it? do I need to use some digital supply instead?

Thanks, Amitai

 

[doraemon]

Hello!

If you connected your BT module directly to 9V, it's probably dead.
What you need is a voltage regulator. If you want to save energy, don't use a linear,
but a switching (buck) converter. If you use a linear converter, you will loose 2/3 of
the battery power.

Dora.

 

[kam1787]

https://www.egr.msu.edu/classes/ece...oup01/resources/HuanLin480ApplicationNote.pdf
https://www.sparkfun.com/products/526
**broken link removed**