# PIR Sensor

**URL:** <https://community.sparkfun.com/t/pir-sensor/32714>\
**Category:** SparkFun Site Questions/Comments\
**Created:** [April 1, 2016, 5:23pm UTC](https://community.sparkfun.com/t/pir-sensor/32714 "2016-04-01T17:23:14Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![tuneking](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@tuneking](https://community.sparkfun.com/u/tuneking)\
**Post date:** [April 1, 2016, 5:23pm UTC](https://community.sparkfun.com/t/pir-sensor/32714/1 "2016-04-01T17:23:14Z")

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I am using a PIR (HC-SR501) that has a 5 volt input. I want to use it to turn on a laser requiring 4.5 volt input. But when the PIR is energized, the output is only 2.8 volts, not enough to power my laser. Is something wrong with the laser? Is there a way to alter the PIR? Or could I add another battery in series to increase the voltage available to the laser? Any thoughts would be appreciated.

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