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Powering 12v sensor

PostPosted: Thu Apr 16, 2015 6:38 am
by StreamingMeeMee
I have a PIR sensor I want to use with this board. The spec. sheet indicates it will work down to 5v but it is quite unstable so I need somewhere around 10-12v. I'm thinking of using a buck converter on the 3.3v rail to get up to ~12v. The current draw is quite low at rest, something like 50uA; I don't know the current when triggered. The intended use is within my mailbox so the number of triggers is quite low, on the order of 2x per day. ;-)

I'm sure there is a better way; thoughts?

Re: Powering 12v sensor

PostPosted: Tue Apr 21, 2015 3:51 pm
by Daniel
If you need a sensor to detect the mailbox being opened I would use a tilt sensor or a reed switch and magnet. Both are easy to use without another power supply and are small and easy to mount.

If you need to power a 12V sensor then you need a boost converter. I don't know of low cost boost converters with 12V output because most ICs are manufactured in 5V processes since most boost applications are for a 3.3V supply from a single AA cell.

Re: Powering 12v sensor

PostPosted: Wed Apr 22, 2015 5:35 am
by StreamingMeeMee
Yes, I considered a reed switch but I wanted to avoid adding any 'wires and stuff' to the door area so as not to alarm the mail carrier. Also, I didn't want anything that could be knocked loose (magnets, etc.) attached to the door. During the winter months the box is subjected to some serious pounding from flying snow propelled by fast moving plows.

Sorry, I did say 'buck' but I did mean 'boost'. I have a few inbound from China. I'll update after I have a chance to give it a try.