• 2019-03-28 first edition
• 2021-11-22 bullseye
• 2023-10-24 bookworm
• 2024-03-07 Raspberry Pi 5

VoiceCAP

• Voice Control Board for Raspberry Pi Zero/ZeroW

Features

• Infrared controller with your voice
• Stand-alone use, no need internet
• You need to customize recognized words.

Note

• No warranty
• Hobby use only
• Not included stereo microphone
• The voice recognition rate is NOT 100%.
• Not all IR format supported.

Information

• as 2024-03-07
• Raspberry Pi 2B/3B/3B+/4B/5B/Zero/ZeroW/Zero2W
• NOOBS 3.0(kernel 4.14.x、4.18.x、4.19.x)
• bullseye (kernel 5.10.x)
• bullseye (kernel 6.1.x)
• bookworm (kernel 6.1.x)
• Julius 4.6
• no Raspberry Pi 3A+
• no NOOBS Lite

How to work

• "Julius" is voice recognition engine.
• "Julius server" can recognize your voice.
• "Julius client(remocon.py)" dispatches each shell by order of your voice command.
• Each shell does something to do. Sending infrared ray to control your TV.
• http://julius.osdn.jp/

Requirement

• Raspberry Pi Zero/W/WH set with 16GB microSD card
• Microphone with 3.5mm stereo 3 terminals. AT9902(audio-technica)

Do not use a microphone with 3.5mm 4 terminals

Before installing VoiceCAP software

• Format 16GB microSD card with SD Memeory Card Formatter
• Install NOOBS not NOOBS LITE

How to install VoiceCAP software. It takes 90 minutes

• wget http://einstlab.web.fc2.com/RaspberryPi/VoiceCAP.tar
• tar xvf VoiceCAP.tar
• cd VoiceCAP
• ./install.sh
• sudo reboot

Do not apt-get update and apt-get upgrade after installing VoiceCAP. PCM1808 driver may not work.

How to control IR

NEC and AHEA format only.
To receive IR

• cd ~/VoiceCAP/Remocon
• sudo ./getIR2 -n
• AEHA 48 2 32 176 0 76 252

To send IR

• cd ~/VoiceCAP/Remocon
• sudo ./setIR2 AEHA 48 2 32 176 0 76 252

Preset voice command list

voice command	shell
"max"	name.sh
"turn on the tv"	onTV.sh
"turn off the tv"	offTV.sh
"turn on the aircon"	onAIRCON.sh
"turn off the aircon"	offAIRCON.sh
"turn on the light"	onLED1.sh
"turn off the light"	offLED1.sh
"channel up"	chUP.sh
"channel down"	chDOWN.sh
"channel one"	ch1.sh
"channel two"	ch2.sh
"channel four"	ch4.sh
"channel five"	ch5.sh
"channel six"	ch6.sh
"channel seven"	ch7.sh
"channel eight"	ch8.sh

You need to customize each shell to adapt your appliance.

Before start

Voice command list consists of vocabulary and grammar.
Set command vocablary as pronunciation

• edit ~/VoiceCAP/en/command.voca
• You can find a pronunciation.
• grep hello ~/julius-master/ENVR-v5.4.Gmm.Bin/ENVR-v5.3.dct

Set command grammar

• edit ~/VoiceCAP/en/command.grammar

Build command

• cd ~/VoiceCAP/en
• mkdfa.pl command

Edit julius client(remocon.py)

• edit ~/VoiceCAP/en/remocon.py

Make or edit each shell

• edit ~/VoiceCAP/Remocon/onTV.sh

To start and stop Julius

To start Julius

• cd ~/VoiceCAP/en
• ./start.sh

To stop Julius

• cd ~/VoiceCAP/en
• ./stop.sh

see also /etc/rc.local
Julius will start automatically in boot.

How to use

To wake up

• "Max" is the name as wake word.
• You will see LED flash twice.
• Voice command will be valid within 10 sec. So time out is 10 sec.

To command

• Then say voice command within 10 sec.
• Try one more if not work.

Julius client judges the score of recognized confidence, if more than 90%. Rejecting the word if less than 90%.

Additional information

To reduce CPU load

• Use CLI
• normal CPU load is 35%

To shutdown OS

• Push the switch and hold more than 5 sec

How to see IR

• You can see IR with digital camera.
• Watch IR LED.
• $ cd ~/VoiceCAP/Remocon
• $ sudo ./setIR2 AEHA 48 2 32 176 0 61 141

To check PCM1808 driver

• $ cd ~/VoiceCAP/en
• $ ./stop.sh
• $ arecord -l
• **** List of CAPTURE Hardware Devices ****
• card 0: sndrpipcm1808ad [snd_rpi_pcm1808_adc], device 0: PCM1808 ADC HiFi pcm1808-dai-0 []
• Subdevices: 0/1
• Subdevice #0: subdevice #0

To check recording your voice via microphone

• $ cd ~/VoiceCAP/en
• $ ./stop.sh
• $ arecord -vD hw:0,0 -c 2 -d 10 -r 48000 -f S16_LE test.wav
• play the test.wav
• If you have any problem,
• check microphone terminal contact
• check solder jamper, SJ1=open, SJ2=open, SJ3=short

To check Julius

• $ cd ~/VoiceCAP/en
• $ ./stop.sh
• Julius server and Julius client on each terminal
• $ ./server.sh
• $ ./remocon.py