r = STRIG(1) s/b r = STRIG(0) depending on your system.
Update: you should be able to download the code now if you could not already.
Part II: https://www.instructables.com/id/Security-with-a-old-Pentium-1-Part-II/
Also check out: https://www.instructables.com/id/Computerized-video-security-setup/
Step 1: What's Needed.
An old computer with a joystick port, 3 1/2 inch floppy drive, and a network card. (Cdrom and hard drive not required)
Nearby wall phone plug
Modem (to have th system dial your cellphone or where ever)
Several magnetic alarm contacts. (nc - normally closed)
Lots of almost invisible wire.
DB15 male joystick connector
A shield for same
momentary push button switch for disarming.
MSdos disk with a basic interpreter (i.e. qbasic).
Step 2: Documentation
Traditional joystick pinout.
The base code for the project written in basic. (you may have to change the code depending on the dialect.
Step 3: Wiring
Attach magnetic alarm contact switch to a door per it's instructions.
Cut two wires long enough to go from the computer to the
Solder one wire end to pin 2 of the joystick port connector and the other end to one side of the magnetic alarm contact switch
Solder another wire to pin 4 of the joystick port connector and the other end to the other side of the magnetic alarm contact switch
Solder the momentary switch to pins 10 and 12 separately to each side of the switch.
Use staples to attach the wire to the wall between the door and the computer.
Plug the joystick connector into the joystick port.
Plug the computer into the UPS and the UPS into the wall.
Step 4: Getting the Code Into the System.
You will want to make a dos bootable 3 1/4 inch dos disk. See your system manual on how to do this.
Copy lizzysasaf.bas, qbasic.exe, and edit.com to the floppy.
You will used edit to create or modify autoexec.bat so that the following is the last line.
This will autorun the program when you start the system.
Step 5: Testing
In the code PRINT #2, "ATDT1234567;", change 1234567 to the number your want called. If you do not want the modem feature, just do not connect the phone line to the wall. Now I have the system send me an email message from the computer network but that is a lot more involved than I want to get into here.