About function generators

I need to convert 15v battery voltage to 12v 400hz (roughly).

Using arduino would be overkill.

What is your reccomendation to do this mechanically?

Thank you



Thank you Mr Paul for your answer.

I have googled Motor-generator but only motors show up. Can you clearify please?

Here are some 400Hz motor-generators intended for 60Hz AC. The google search terms were "motor generator 400 hz"

For DC input, look for "400 hz dc to ac converter". You may want a pure sine wave converter like this one, which are more expensive than square wave converters.