Today I decided it was time to build something to give people a better idea of the device I intend to build. So I grabbed a piece of acrylic plastic sheet and started drilling holes to build the actual unit.
Turns out I need to find a better way to drill holes in plastic sheets. When I tried to drill 3/8 inch holes for the solenoids with a normal drill bit it would chatter and I figured it would break the plastic before I got the hole drilled. So I used my Dremel drill press and a somewhat cone shaped grinding stone to make the holes. Problem was that it basically melted through the plastic and didn't stay centered where I wanted so the holes aren't aligned as well as I wanted. I suppose when I build a final version I'll have to make some sort of jig to hold things in place as I drill. And I scratched up the plastic a bit scraping the melted mess off around the holes. But it's a workable first attempt and does a good job of showing what I intended.
As you can see I also drilled holes in the corners and mounted a couple flat head screws. I put magnets on the heads of the screws to hold the device to the door. I need to order some magnets with holes in the center for screws. And add two more to the bottom corners. Using screws in this way will allow me to adjust the space between the keypad and the solenoids, allowing me to find that optimal height with the most solenoid force. And the acrylic sheet plastic makes it easier to see the alignment of the solenoids with the keypad and just looks cool.
Also mounted on this plastic sheet would be the Arduino, LCD, a board with the ULN2003 driver chip, and the push button switches (maybe I need a bigger piece of plastic).