I have a the following PIR Motion sensor working: https://www.sparkfun.com/products/8630
. The output of the sensor (HIGH when motion is detected) goes into the input of my Arduino and all works great.
Now I'd like to run the sensor in "standalone" mode. The PIR sensor only needs power to operate and the output gives 3V, so you can attach a LED to it directly. But instead of the LED, I'd like to have an Arduino, which needs more power than the 3V (I tried connecting a 3.3V Arduino, but the output is not sufficient).
My guess is that I need to use a MOSFET/transistor (that is connected to the output of the PIR motion sensor) which powers the 2nd circuit (the Arduino). Can somebody confirm? Also I'd love to learn which MOSFET/transistor I need to use.
Some additional info: the PIR motion sensor keeps the HIGH output for a while (configurable), so I do *not* need a mechanism that is triggered and stays active longer than the HIGH output. Also, I'd like to run this thing on batteries. So in an ideal scenario the MOSFET/transistor or 2nd circuit don't consume any power when not activated.
Thanks for your help!