embed-pi

Installation setup

$ sudo apt install hostapd wireless-tools dnsmasq iw wpasupplicant
$ git clone https://github.com/ForkEat/embedpi.git
$ cd embedpi
$ sudo cp dev/configs/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf
$ go build
$ pkill wpa_supplicant
$ sudo ./embed

Developpement setup

# Go install #
# Change pi password before or remove warning
$ git clone https://github.com/udhos/update-golang
$ cd update-golang
$ sudo ./update-golang.sh
$ nano /home/pi/.bashrc
> export GOROOT=/usr/local/go
> export GOPATH=$HOME/go
> export PATH=$GOPATH/bin:$GOROOT/bin:$PATH
$ source /home/pi/.bashrc
$ mkdir /home/pi/go && mkdir /home/pi/go/src

# Install zbar
$ sudo apt install libzbar0 zbar-tools libzbar-dev

# Txwifi requirements
$ sudo apt install dnsmaq iw wireless-tools hostapd 

# Install OpenCV
$ sudo nano /etc/dphys-swapfile
> CONF_SWAPSIZE=1024
$ sudo /etc/init.d/dphys-swapfile restart
$ sudo apt update
$ sudo apt install build-essential cmake git pkg-config libgtk-3-dev "libcanberra-gtk*"
$ sudo apt install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev libxvidcore-dev libx264-dev
$ sudo apt install libjpeg-dev libpng-dev libtiff-dev gfortran openexr libatlas-base-dev opencl-headers libopencv-dev
$ sudo apt install python3-dev python3-numpy libtbb2 libtbb-dev libdc1394-22-dev
$ mkdir ~/opencv_build && cd ~/opencv_build
$ git clone https://github.com/opencv/opencv.git
$ git clone https://github.com/opencv/opencv_contrib.git
$ mkdir -p ~/opencv_build/opencv/build && cd ~/opencv_build/opencv/build
$ cmake -D CMAKE_BUILD_TYPE=RELEASE \ -D -DOPENCV_GENERATE_PKGCONFIG=ON -D CMAKE_INSTALL_PREFIX=/usr/local \ -D INSTALL_C_EXAMPLES=OFF \ -D INSTALL_PYTHON_EXAMPLES=OFF \ -D OPENCV_GENERATE_PKGCONFIG=ON \ -D ENABLE_NEON=ON \ -D OPENCV_EXTRA_EXE_LINKER_FLAGS=-latomic \ -D ENABLE_VFPV3=ON \ -D BUILD_TESTS=OFF \ -D OPENCV_ENABLE_NONFREE=ON \ -D OPENCV_EXTRA_MODULES_PATH=~/opencv_build/opencv_contrib/modules \ -D BUILD_EXAMPLES=OFF ..
$ make -j4
$ sudo make install
$ sudo pkg-config --cflags --libs opencv4

$ rm -rf ~/opencv_build
$ sudo nano /etc/dphys-swapfile
> CONF_SWAPSIZE=100
$ /etc/init.d/dphys-swapfile restart

Connect to the Pi over Wifi

On your laptop or phone, you should now see a Wifi Network named iot-wifi-cfg-3 assuming you did not change it from the default. The default password for this network is iotwifipass. Once connected to this network you should get an IP address assigned to the range specified in the config: 192.168.27.100,192.168.27.150,1h.

Once connected open a web browser and go to http://192.168.27.1:8080/status. You can access this API endpoint on the Raspberry Pi device itself from localhost*. On on Pi try the curl command curl http://localhost:8080/status.

You should receive a JSON message similar to the following:

{"status":"OK","message":"status","payload":{"address":"b8:27:eb:fe:c8:ab","uuid":"a736659a-ae85-5e03-9754-dd808ea0d7f2","wpa_state":"INACTIVE"}}

From now on I'll demonstrate API calls to the new container with the curl command on the device. If you were developing a Captive Portal or configuration web page, you could translate these calls into Javascript and control the device Wifi with AJAX.

You can use my simple static web server IOT Web container for hosting a Captive Portal or configuration web page. See https://github.com/cjimti/iotweb.

To get a list of Wifi Networks the device can see, issue a call to the scan endpoint:

curl http://localhost:8080/scan

Connect the Pi to a Wifi Network

The device can connect to any network it can see. After running a network scan curl http://localhost:8080/scan you can choose a network and post the login credentials to IOT Web.

# post wifi credentials
$ curl -w "\n" -d '{"ssid":"home-network", "psk":"mystrongpassword"}' \
     -H "Content-Type: application/json" \
     -X POST localhost:8080/connect

You should get a JSON response message after a few seconds. If everything went well you will see something like the following:

{"status":"OK","message":"Connection","payload":{"ssid":"straylight-g","state":"COMPLETED","ip":"","message":""}}

You can get the status at any time with the following call to the status endpoint. Here is an example:

# get the wifi status
$ curl -w "\n" http://localhost:8080/status

Sample return JSON:

{"status":"OK","message":"status","payload":{"address":"b7:26:ab:fa:c9:a4","bssid":"50:3b:cb:c8:d3:cd","freq":"2437","group_cipher":"CCMP","id":"0","ip_address":"192.168.86.116","key_mgmt":"WPA2-PSK","mode":"station","p2p_device_address":"fa:27:eb:fe:c9:ab","pairwise_cipher":"CCMP","ssid":"straylight-g","uuid":"a736659a-ae85-5e03-9754-dd808ea0d7f2","wpa_state":"COMPLETED"}}

Check the network interface status

The wlan0 is now a client on a wifi network. In this case, it received the IP address 192.168.86.116. We can check the status of wlan0 with ifconfig*

# check the status of wlan0 (wireless interface)
$ ifconfig wlan0

Example return.

wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.86.116  netmask 255.255.255.0  broadcast 192.168.86.255
        inet6 fe80::9988:beab:290e:a6af  prefixlen 64  scopeid 0x20<link>
        ether b8:27:eb:fe:c8:ab  txqueuelen 1000  (Ethernet)
        RX packets 547  bytes 68641 (67.0 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 36  bytes 6025 (5.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

We can also check the connection by issuing a ping command from the device and specify the network interface to use:

# ping out from the wlan0 interface
$ ping -I wlan0 8.8.8.8

Hit Control-C to stop the ping and get calculations.

PING 8.8.8.8 (8.8.8.8) from 192.168.86.116 wlan0: 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=57 time=20.9 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=57 time=23.4 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=57 time=16.0 ms
^C
--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 16.075/20.138/23.422/3.049 ms