B
BlackMamba
Guest
Project by denwer
Source here
Standard voice control devices are expensive or unreachable. So I replaced them by telephone.
A heart of device are ATmega8 and Siemens S35. S35 is connected to microcontroller via RS232C. For communication AT commands are used.
Microcontroller checks every 0.5 sec if phone is not realizing call. If so, then it checks the number, disconnects call and switches state on relevant pin dependant on the number.
Number is picked by a voice command. Unfortunately, to activate it two buttons should be pressed I did it manually, but two transistors controlled by microcontroller may be used as well.
Circuit was mounted on test board ZL2AVR.
In upper right corner there are two LED’s connected to microcontroller. Their state changes every time the phone receives relevant voice keyword.
Advantages:
-relatively cheap solution (eg. A phone with faulty LCD may be used)
-simplicity
-may be used in many applications
Disadvantages:
- unfortunately device cannot receive signals continuously and command can be uttered only after specific event. (e.g. pressing two keys – in this case „2” and „green ear-piece”)
- you have to wait some time before receiving second command.
- if command will be faulty you have to wait for telephone going to main menu
- reaction for change of state after uttering keyword less some time