By mistake I bought an Adruino Pro Mini 5V instead a 3.3V.
I have a Lipo 3.7V, 1000mAh.
I've read that I have to use a "Convertor" to power the Pro Mini 5V with a 3.7V Lipo.
But I'm unsure what kind of specifications this "Convertor" needs.
Can anybody please direct me to the right product ?
Or is there another way to use the 3.7V Lipo with Pro Mini 5V ?
Here are a couple of options.
There are Dc-Dc step up converter such as this one https://www.sparkfun.com/products/10968.
There are probably cheaper sources than sparkfun but this is an example.
The arduino won't reliably run at 16 Mhz much below 5 volts.
You could burn a bootloader to use the internal clock at 8 Mhz. The Board will then run on 3 volts and above. You will want to plug your lipo in to the VCC pin rather than RAW.
You could also get a 2s (7.4v) Lipo instead and use it as is. You can probably find one that size for under 10 dollars.