Hi,
The Voice Control System (VCS) is progressing well.
I’m now using an Andrea ANC-700L Anti-noise headset (following TugCowboy’s advice) that has two microphones – one pointing to the voice and the other “listening” to the background noise, resulting in the noise being subtracted from the voice.
I’ve used it very successfully with a radio as the background “noise”.
Using an oscilloscope on the UART serial output, I can relate the different voiced commands to the bit pattern which is useful in determining repeatability of the those commands.
By using the PC based “Speakup” editor (free download), each voice command can be linked to any of the twelve digital outputs and all commands can be linked to the same output, if so desired.
The digital output can be switched on or off, toggled or pulsed. The pulsed one is particularly useful, since it can be used to generate an audible tone (continuous or for a period) that is fed to the headphone of the headset to indicate that the spoken command has been recognised.
Each command can generate a different tone from the same output to give double confirmation that a command has been understood. To be practical, I would envisage commands being grouped to a limited range of tones to avoid trying to remember the meaning of each tone.
The actual digital output is fed through an additional 74HC00 NAND gate, which acts as an amplifier with its open collector output connected, via a variable potentiometer volume control, to the headphone.
I’ve been using the “International Radiotelephony Spelling Alphabet” – Alpha, Bravo etc, in addition to Port, Starboard, Left, Right etc. as a comparison of repeatability.
I’ve found that a command with more vowels in it is more reliable, though I draw the line at calling out “Romeo – Romeo” at the pond side knowing the reply I would get from the majority of Mayhemers!
Regarding latency - I’ve found the system quite responsive to the voice and it will be fine for most scale model boat control, but it wouldn’t match the response of a joystick simply because the voice is slower than the hand. On the other hand it promises to give a much broader range of controls for auxiliarys such as lamps, pumps etc.
The next stage is to link the UART serial output to a PIC to decode the commands into PWM signals for the rudder etc. I’ve already got working UART code from a previous project (see
http://www.modelboatmayhem.co.uk/forum/index.php/topic,48575.25.html ), so I’m more than halfway through the VCS project.
Ian