VOICE RECOGNITION HM2007 BOARD
HM2007 speech recognition IC is made by HUALON Microelectronics Corporation(Taiwan) .
The IC can recognize 20 words, each word a length of 1.92 seconds.
Speech samples are acquired by a Microphone on board.HM2007 analyzes the analog signal received compares with the data stored in external RAM & finally outputs a corresponding 8 bit Data.This 8 bit data can be directly connected to a port of Microcontroller for further action.
An 8 kB external RAM is needed to store data.As the RAM is volatile , a 3v button battery is used to backup stored data.The 8 bit data is passed through an octal latch IC 74HC573.
To display the command numbers 2 common cathode 7 segment displays are provided.This is driven by a BCD to 7 segment decoder/driver IC CD4511.
The board requires 5v DC supply. A 12v adapter can be used as a power source, as the board has inbuilt 5v regulator with heat sink.
The HM 2007 IC requires initial configuration or training of words, which is performed using a 4 x 3 Matrix Keypad. In the training process user trains the IC by speaking words into the microphone and
assigning a particular value for that word. For example a world “left” can be assigned a value 01.This can then be later connected to a microcontroller for further functions.
Words can be assigned from 01 to 20.
Training Words for Recognition:
Before starting the training process we can erase the previous memory.
Press 99 & then press the CLEAR button.
The display will scroll from 01 to 20 erasing all the memory
To train a word
Press “01” on the keypad.Display will show “01” and the READY LED will turn off.Now press the TRAIN key ( the LED will turn on) & HM2007 goes to training mode, for word one.
Say the target word into the onboard microphone (near LED) clearly. The READY LED should blink momentarily indicating the acceptance of word.
If the LED did not flash, start again by pressing “1” and then “TRAIN” key.
You may continue training new words in the circuit. Press “02” then TRAIN key to train the second word and so on. The circuit will accept and recognize up to 20 words (numbers 01 through 20).
It is not necessary to train all word spaces. If you only require 5 target words that’s all you NEED TO TRAIN.
If the system has to work under noisy environments, background noise may corrupt the original data and leads to malfunctioning.Take care to avoid using this board in Noisy places.
Error codes generally displayed
55 = word too long
66 = word too short
77 = word no match
Tutorials on how to control a motor with HM2007 VOICE COMMANDS