Hi
I was hoping for the option to plug them in, can they be wired to do so?
They can, I have one that I power from 3 volt "wall wart". But...they are very sensitive to "ripple" on the DC supply. I had to add extra capacitive filtering before my Active Eye would work. However, depending on the amount of traffic the sensor sees, the batteries can last a year or more, so putting them on power supplies may be more trouble than it is worth. Unless you back-up the wired power supply with re-chargable batteries, everytime you lose power, you will have to reprogram the sensor.
If you are still worried about replacing batteries... I also have a couple Eagle Eyes that, because of location, I power with D cells rather than AA cells. A 2 "D" cell battery holder hot glues perfectly to the back of the Eagle Eye. The battery weight is a great stabilizer, so the sensor becomes more "placeable" for a longer time ( i.e. jammed in the fork of a tree for two years).
FWIW To any of you "surplus" guys out there; Electronic Goldmine (
www.goldmine-elec.com) has 3V DC switching wall warts for $1.29 each. A surplus Radio Shack brand power adapter for Game Boys. They have a clean 350ma output. What a deal, I bought ten. So far I am only using three, but they tolerate being controlled by Socket Rockets and they don't "noise-up" the powerlines enough to effect X10. FWIW