Since you also need a USB-to-serial converter, either of these boards include onboard 3.3 V regulated power output, probably with enough current to run a microcontroller:<p><a href="https:&#x2F;&#x2F;www.sparkfun.com&#x2F;products&#x2F;11736" rel="nofollow">https:&#x2F;&#x2F;www.sparkfun.com&#x2F;products&#x2F;11736</a><p><a href="http:&#x2F;&#x2F;www.adafruit.com&#x2F;products&#x2F;284" rel="nofollow">http:&#x2F;&#x2F;www.adafruit.com&#x2F;products&#x2F;284</a><p>In addition, this is an easy to apply 3.3 V regulator chip, in a package that&#x27;s compatible with a breadboard:<p><a href="https:&#x2F;&#x2F;www.adafruit.com&#x2F;products&#x2F;2166" rel="nofollow">https:&#x2F;&#x2F;www.adafruit.com&#x2F;products&#x2F;2166</a>