Animatronic Mouths

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The LCD Mouth Theory
           Now let's switch gears and take a look at a much easier way to build a robotic mouth. I wouldn't call this design an animatronic mouth since it doesn't even move! None-the-less it is a widely used and accepted way for a robot to be seen speaking.

16x2 LCD Custom Characters

           If we build up a set of custom characters in a 16x2 LCD like seen above, we have something that looks like a mouth. Unfortunately the 16x2 LCD displays usually only have space for 8 custom characters so you are somewhat limited to what you can build into it, but you can definitely work with it. Beyond simply displaying the characters, we also want to control the backlight. To do this we connect the backlight control to a transistor that can be switched on and off via a signal from the PIC.

Flashing Backlight vs. Spectrograph

           The theory for making a robot talk using an LCD is rather simple, if the robot should be talking, the mouth should be lit up bright. In between speaking words the mouth should not be lit, creating a different illusion that speaking is actually happening. An alternative design that could be built is a spectrographic mouth (also seen above). This would be very similar to the LCD mouth, however it would also move dynamically as words are spoken, thus furthering the illusion that a robot is talking. For this tutorial, I'll limit it to the LCD backlight flashing.