PiBot

UI

Circuit Diagram

Motor Driver and Motors

The "9v" battery is actually two 3.7v 18650 batteries.

Servo

The "9v" battery is actually two 3.7v 18650 batteries.

Temperature and Humidity Sensor

IR Receiver

IR Transmitter

Install Prerequisites

1) Python 3.x

If which python3 returns nothing, run sudo apt-get install python3

2) NodeJs 8.x

curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
sudo apt install nodejs
node -v

3) Nginx Server

Install the nginx package sudo apt-get install nginx and start the server sudo /etc/init.d/nginx start

4) Audio & Video related

Install the library for ALSA applications development files: sudo apt-get install libasound2-dev . If you got 404 Not Found, run sudo apt-get upgrade --fix-missing

avconv is needed for converting recorded videos to .mp4 format: sudo apt-get install libav-tools

mpg123 is used for playing .mp3 format music: sudo apt-get install mpg123

5) Clone the repo

cd ~
git clone https://github.com/shaqian/PiBot.git

Set up and Test Hardware Components

1) Motor driver and motors

Do not install the wheels when testing.

• Refer to the circuit diagram and connect the wires.

• Install rpio, run npm install rpio

• Start node, run node

• Initialize output:

var rpio = require('rpio');
rpio.open(29, rpio.OUTPUT, rpio.LOW);
rpio.open(31, rpio.OUTPUT, rpio.LOW);
rpio.open(38, rpio.OUTPUT, rpio.LOW);
rpio.open(40, rpio.OUTPUT, rpio.LOW);

• Go forward:

rpio.write(29, rpio.LOW);
rpio.write(31, rpio.HIGH);
rpio.write(38, rpio.LOW);
rpio.write(40, rpio.HIGH);

• Go backward:

rpio.write(29, rpio.HIGH);
rpio.write(31, rpio.LOW);
rpio.write(38, rpio.HIGH);
rpio.write(40, rpio.LOW);

• Stop:

rpio.write(29, rpio.LOW);
rpio.write(31, rpio.LOW);
rpio.write(38, rpio.LOW);
rpio.write(40, rpio.LOW);

2) Servo

• Refer to the circuit diagram and connect the wires.

• Run:

cd ~/PiBot/PiBotServer/bin
chmod +x direct.py

• The position is controlled by duty cycle, normally ranges from 2.5 to 11.5. Go to middle position:

./direct.py 7

• Full left:

./direct.py 2.5

• Full right:

./direct.py 11.5

3) Temperature and Humidity Sensor

• Refer to the circuit diagram and connect the wires.

• Run:

cd ~/PiBot/PiBotServer/bin/temp_hum
chmod +x getTemp.py
chmod +x getHum.py

• Get temperature:

./getTemp.py

• Get humidity:

./getHum.py

4) IR Receiver

I use IR Receiver to read IR signal from remote controls of home appliances, then emulate the remote control by sending the same signal from Raspberry P.

I borrowed the code from this repo but changed the ports as well as the value of ST_BASE which was 0x20003000 for older Raspberry Pi but should be 0x3F003000 for Raspberry Pi 3 (BCM2837).

• Refer to the circuit diagram and connect the wires.

• Run gpio -v to check if wiringPi is already installed. If not, install Wiring Pi.

• Run cd ~/PiBot/PiBotServer/bin . Compile the code and generate the binary:

gcc ir_decode.c -lwiringPi -o decode.out
chmod +x decode.out

• Run sudo ./decode.out . It would print [0] every one second when no IR signal is received.

• Point the remote control to the IR receiver and press the button. The decoded IR signal is a series of hex numbers, ie: 0xb2,0x4d,0x1f,0xe0,0x98,0x67,[48].

• Repeat the same for "ON" button and "OFF" button, and note down the IR signals.

5) IR Transmitter

Disconnect the IR Receiver as we are done with IR decoding.

• Refer to the circuit diagram and connect the wires.

• Run the following to duplicate the ir_encode code.

cd ~/PiBot/PiBotServer/bin
cp ir_encode.c on.c
cp ir_encode.c off.c

Run vi on.c , and change the hex string in line 166 to what you have decoded, ie:

char data[6] = {0xb2,0x4d,0x1f,0xe0,0xd8,0x27};

Run vi off.c , and change the hex string in line 166 to what you have decoded, ie:

char data[6] = {0xb2,0x4d,0x7b,0x84,0xe0,0x1f};

• Compile the code and generate the binary:

gcc on.c -lwiringPi -o on.out
chmod +x on.out
gcc off.c -lwiringPi -o off.out
chmod +x off.out

• Send "ON" signal: sudo ./on.out .

• Send "OFF" signal: sudo ./off.out .

6) Sound Card, Microphone and Speaker

Raspberry Pi has a built-in 3.5mm jack for audio output but no input. I use a USB sound card for both speaker output and microphone input.

• Plug the USB sound card in. Connect the microphone and speaker to the sound card.

• Run arecord -l and aplay -l and identify card number of your USB Audio Device, e.g. card 1.

• Record a 5 seconds test audio: arecord -Dplughw:[n] -fcd -d5 -c1 -twav -r16000 test.wav (replacing [n] with the number of USB Audio Device, e.g. Dplughw:1).

• Play the test audio: aplay -Dplughw:[n] test.wav (replacing [n] with the number of USB Audio Device, e.g. Dplughw:1).

• To set the USB sound card to be the default audio device, run sudo vi /lib/modprobe.d/aliases.conf , insert the following and save:

options snd_usb_audio index=0
options snd_bcm2835 index=1
options snd slots=snd_usb_audio,snd_bcm2835

• Reboot: sudo reboot .

• Run cat /proc/asound/modules and you should have:

0 snd_usb_audio
1 snd_bcm2835

Play the .wav again without specifying device: aplay test.wav .

7) Camera

I use picam to generate HTTP Live Streaming (HLS).

• Connect Raspberry Pi Camera Board to the Raspberry Pi.

• Run sudo raspi-config , navigate to Interfacing Options and select Camera > Yes.

• Install dependencies for picam:

sudo apt-get update
sudo apt-get install libharfbuzz0b libfontconfig1

• Create directories and symbolic links:

cd ~;mkdir picam;cd picam
cat > make_dirs.sh <<'EOF'
#!/bin/bash
DEST_DIR=~/picam
SHM_DIR=/run/shm
mkdir -p $SHM_DIR/rec
mkdir -p $SHM_DIR/hooks
mkdir -p $SHM_DIR/state
mkdir -p $DEST_DIR/archive
ln -sfn $DEST_DIR/archive $SHM_DIR/rec/archive
ln -sfn $SHM_DIR/rec $DEST_DIR/rec
ln -sfn $SHM_DIR/hooks $DEST_DIR/hooks
ln -sfn $SHM_DIR/state $DEST_DIR/state
EOF
chmod +x make_dirs.sh
./make_dirs.sh

• Install picam library:

wget https://github.com/iizukanao/picam/releases/download/v1.4.6/picam-1.4.6-binary-jessie.tar.xz
tar xvf picam-1.4.6-binary-jessie.tar.xz
cp picam-1.4.6-binary-jessie/picam ~/picam/

• Start HTTP Live Streaming:

cd ~/picam
./picam -o /run/shm/hls

Configure Nginx server. Run sudo vi /etc/nginx/sites-available/default and add the following inside server { ... } bloc:

location /hls/ {
  root /run/shm;
}

• Restart Nginx:

sudo /etc/init.d/nginx restart

• Test playback:

The HLS will be available at http://[IP-of-Raspberry-Pi]/hls/index.m3u8.

sudo cp ~/PiBot/PiBotServer/public/hls_test.html /var/www/html/hls_test.html

• With QuickTime on a Mac:

• Open QuickTime player, go to File > Open Location, enter http://[IP-of-Raspberry-Pi]/hls/index.m3u8.

• Or playback in a web browser:

• i. Download the test file and copy it to Nginx root.

• ii. From the Raspberry Pi or any PC that in the same network, navigate to http://[IP-of-Raspberry-Pi]/hls_test.html in a web browser.

Configure Nginx

Enable both HTTP on port 80 and HTTPS on port 443. HTTPS is required to get recording working in Chrome when requests are not originated from local host. See: https://goo.gl/rStTGz

• Run sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/nginx/snippets/nginx-selfsigned.key -out /etc/nginx/snippets/nginx-selfsigned.crt to create the certificates used for HTTPS in nginx.

• Replace the content in /etc/nginx/sites-enabled/default with ~/Cognitive-Bot/ngnix/default.

• Run sudo nginx -t to test the configurations. If successful, restart nginx server sudo /etc/init.d/nginx restart .

Run the Web Application

• Run cd ~/PiBot/PiBotServer;npm install to install all dependencies.

• Start HLS video streaming:

cd ~/picam
./make_dirs.sh
./picam -o /run/shm/hls --vflip --hflip

• To start the application, run:

cd ~/PiBot/PiBotServer
sudo npm start

Navigate to http[s]://[IP-of-Raspberry-Pi] in a web browser (replacing [IP-of-Raspberry-Pi] with the actual IP address, ie: 192.168.1.16).

Run the Mobile App

iOS

cd PiBot/PiBotApp
npm install
npm run ios

• Build and run in simulator:

• Run on device:

• Refer to Running your app on iOS devices in React Native official guide.

Android

cd PiBot/PiBotApp
npm install
npm run android

• Build and run in simulator:

• Run on device:

• Refer to Running your app on Android devices in React Native official guide.

• Or use the PiBot.apk in this repo.