This program turns a Radio Shack Model 100 computer into an intervalometer to control an automatic advance camera or motor drive by signals output through the cassette port's remote on/off jack.  WARNING: DO NOT CONNECT YOUR MODEL 100 DIRECTLY TO THE CAMERA.  I used it to trigger a Light-activated Photoresistor Relay which was connected to the motor drives of 3 cameras for simultaneously triggered exposure sequences.  This kept the three cameras, with their motor drives set to single exposure mode, in perfect sychronization with each other.  This would be impossible to achieve by simultaneous triggering on the cameras in their continuous fire mode due to variations in drag, etc. from drive to drive.  The simple photoresister relay switch I made up to interface the cassette remote control jack and the camera motor drive cords appears at the top of page 28 in the Engineer's Mini-Notebook: Optoelectronics Circuits by Forest M. Mims III.  This is a Radio Shack book Catalog No. 276-5012.  Besides triggering multi-camera sequences, this program can let you use a Model 100 to run a single camera for doing time lapse studies, etc. with the camera set to it's single exposure and advance mode. Delete the Rems to save space.  And enjoy, the program is self prompting.