My first Arduino project is a garage door open notification/control. I'm using a Uno and Ethernet shield; to determine whether a door is open/closed I've found some magnetic reed switches.
On the package of the switch it states 500mA @ 12VDC. The data sheet (http://www.mode-elec.com/pdf/switches/47-600.pdf) has the following:
- switching current (max): 0.25A
- switching voltage (max): 30VDC
- insulation resistance: 100Mohms Min
My question is: can this be driven from one of the digital pins of the Uno, or do I need to use an opto-coupler to drive this from a 12V power supply? Does it really require 500mA?
many thanks, J.