SparkFun Forums 

Where electronics enthusiasts find answers.

General suggestions or questions about the SparkFun Electronics website
By tuneking
#189200
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.
User avatar
By TS-Chris
#189239
Hello!

Your PIR module probably doesn't have the ability to deliver the amount of current a laser needs let alone the voltage.

What you want to do is have the PIR module turn on a transistor or MOSFET, and then have the transistor/MOSFET drive the laser from a suitable power source. Something like the SparkFun MOSFET Power Control Kit is probably overkill for a small laser, but would be an easy way to make this work.
long long title how many chars? lets see 123 ok more? yes 60

We have created lots of YouTube videos just so you can achieve [...]

Another post test yes yes yes or no, maybe ni? :-/

The best flat phpBB theme around. Period. Fine craftmanship and [...]

Do you need a super MOD? Well here it is. chew on this

All you need is right here. Content tag, SEO, listing, Pizza and spaghetti [...]

Lasagna on me this time ok? I got plenty of cash

this should be fantastic. but what about links,images, bbcodes etc etc? [...]