[Al Skierkiewicz]

One thing that broadcast pros have been using for years is cue tones recorded with the audio. I would record the descriptive audio tracks on a CD, add a defined length of silence between tracks, left channel only. Record the cue tones on right channel only. (Feed left channel to a speaker and right channel to the decoder.) The tone would signal the robot to move to the next position and the silence would give it time to get there. The tones are easily decoded with a PLL decoder chip and a few external components. 1kHz tones work fine. (NE567 is available from Digikey or Radioshack) You can use a cassette tape player which makes things easier but the audio degrades over time.