The Radio Shack 12 VDC 10A Relay (275-248A) will fit on the MS20 Board, but I don't know if it will work? One of the advantages of building Jesse's version with the 9 Volt Relay is that you know it will work. While you are in Radio Shack look at the (270-1806) 6 X 4 X 2 Hobbie boxes. That is the one we use with the RS 49-425 PIR to make a "clean" little mini cam. If your Owl unplugs, you can I use different enclosure & PIR assemblies (mix & match). The mini cam is nice!
Simplearkansan I don't know where you can get a 12 volt relay for the ms 20. But if it will help I use the 9 volt mini relay 275-005a with a 12 volt batt. on all my cameras and this set up works great. Homer