Enable an RPi to serve as an ioT gateway for our P2 Hardware - while dedicating only 2 pins for serial communication
On this Page:
- Wiring - Wire the serial connection between the P2 Development board and our RPi
- Installation - Install this project and supporting libraries on an RPi
- Configuration - Initial configuration of gateway
- Execution - Test the deamon configuration. Does it all run?
- Configure Daemon run Style - Configure this project to start at every boot
- Update install to latest - Project updated? Update this RPis installation to get latest features
Additional pages:
- Unbox & setup new RPI
- Configure Email Service
- Configure Web Server & PHP
- Configure SMS Service - content TBA
- Configure Twitter Service - content TBA
- Technology/Tools Used in this IoT Gateway
- Developing your own P2 Application using IoT gateway services
- and experience I draw from wihile creating this project: My Prior RPi Efforts
The P2-RPi-ioT-gw-daemon.py script is built to use the main serial I/O channel at the RPi GPIO Interface. These are GPIO pins 14 & 15.
NOTE: FYI a good reference is: pinout diagram for RPi GPIO Pins
RPi Wiring for Daemon use:
| RPi Hdr Pin# | RPi GPIO Name | RPi Purpose | P2 Purpose | P2 Pin # |
|---|---|---|---|---|
| 6 | GND | Signal ground | Signal ground | GND near Tx/Rx Pins |
| 8 | GPIO 14 | Uart Tx | Serial Rx (from RPi) | 25 |
| 10 | GPIO 15 | Uart Rx | Serial Tx (to RPi) | 24 |
Pick two pins on your P2 dev board to be used for RPi serial communications. The demo files provided by this project define these two pins as 24, 25. Feel free to choose different pins. Just remember to adjust the constants in your code to use your pin choices.
On a modern Linux system just a few steps are needed to get the daemon working.
The following example shows the installation under Debian/Raspbian below the /opt directory:
First install extra packages the script needs (select one of the two following commands)
sudo apt-get install git python3 python3-pip python3-tzlocal python3-sdnotify python3-colorama python3-unidecode python3-paho-mqtt python3-watchdogNow that the extra packages are installed let's install our script and any remaining supporting python modules.
sudo git clone https://github.com/ironsheep/P2-RPi-ioT-gateway.git /opt/P2-RPi-ioT-gateway
cd /opt/P2-RPi-ioT-gateway
sudo pip3 install -r requirements.txtWARNING: If you choose to install these files in a location other than /opt/P2-RPi-ioT-gateway, you will need to modify some of the control files which are used when setting up to run this script automatically. The following files:
- p2-rpi-iot-gateway - Sys V init script
- p2-rpi-iot-gateway.service - Systemd Daemon / Service description file
... need to have any mention of /opt/P2-RPi-ioT-gateway changed to your install location before you can run this script as a service.
In this project we've provided scripts you can use routinely on your RPi. The following scrips are found in the /opt/P2-RPi-ioT-gateway/scripts directory. During the setup of your RPi you created a ~/bin directory. And you adjusted your login (by editing ~/.profile) so that any scripts in ~/bin can be run my name (without providing any path to them.) So let's copy these new script to your ~/bin directory:
cp -p /opt/P2-RPi-ioT-gateway/scripts/* ~/bin # -p means preserve file times, permissions, etc.NOTE: if you appear to be missing the ~/bin directory please refer back to the section Install the latest software Updates of the "Unbox & setup new RPI" instructions where this directory was first made.
Our Gateway knows of seven directories we'll be using. These directories do not yet exist when you are first installing this project.
There are two helper shell scripts that installed along side our Daemon python script. These are scripts/lsGwDirs and mkGwDirs.
Let's create the needed directories by running:
sudo ./mkGwDirs # create the needed Daemon directoriesNow let's list ths directories we just created:
lsGwDirs # list all gateway directories and the files in themNOTE: we didn't provide a path or use sudo in this case. This is because we just placed lsGwDirs in your ~/bin and it should have been found automatically because of being in ~/bin.
This was practice! As you are creating projects that use our gateway you will want to locate files that your P2 project or a new web-backend page created. You will use lsGwDirs to list the files that have been created any time you need to find them or remember their names, etc.
To match personal needs, all Deamon operational details can be configured by creating and then modifying entries within the config.ini file. A template is provided config.ini.dist.
To create the file: (in the following: if you don't have vim installed you might try nano)
sudo cp /opt/P2-RPi-ioT-gateway/config.{ini.dist,ini}
sudo vim /opt/P2-RPi-ioT-gateway/config.iniThere are two possible reasons to adjust your config.ini at this release version:
hostname --fqdnreturns only a machine name and no domain (Only if your location is setup with its own domain - some homes are not!)
- FIX: uncomment
fallback_domainin [DAEMON] section and enter the domain for your RPi
fallback_domain = {if you have older RPis that dont report their fqdn correctly}- You want to use a SendGrid account to send email instead of
Sendmail
- FIX: uncomment sendgrid entries within the [EMAIL] section and fill in details of your sendgrid account
use_sendgrid = true
# ...
sendgrid_api_key = {api_key}
# ...
sendgrid_from_addr = {sendgridFromAddress}
NOTE If you are using SendGrid there are more complete setup instructions which you will follow in later steps when you get to the Configure Email Service step.
Now that your config.ini is setup let's test!
A first test run is as easy as:
sudo python3 /opt/P2-RPi-ioT-gateway/P2-RPi-ioT-gw-daemon.py -d -vNOTE: it is a good idea to execute this script by hand this way each time you modify the config.ini. By running after each modification the script can tell you through error messages if it had any problems with any values in the config.ini file, or any missing values. etc.
NOTE2: the optional command line options -d and -v enable debug and verbose runtime options that can possibly provide more detail if you are experiencing problems!
Additionally, the optional command line argument --config, can be used to specify a directory from where to read the config.ini file, e.g.
sudo python3 /opt/P2-RPi-ioT-gateway/P2-RPi-ioT-gw-daemon.py --config /opt/P2-RPi-ioT-gatewayNOTE3: if you seem to have communications issues with serial it may be because you didn't disable the "console over serial port" feature. The symptoms of this are discussed in P2 Forum thread You need to ensure you kept the serial port operational but turned off the "console over serial port" feature. Review the section Setting up your 1st Raspberry Pi: Configure services you need to double check your initial RPi configuration effort.
In order to have your HA system know if your RPi is online/offline and when it last reported-in then you must set up this script to run as a system service.
NOTE: Daemon mode must be enabled in the configuration file (default).
But first, we need to grant access to some hardware for the user account under which the sevice will run.
By default this script is run as user:group daemon:daemon. As this script requires access to the serial uart you'll want to add access to it for the daemon user as follows (note: serial access is controlled by the 'dialout' group/permission):
# list current groups
groups daemon
$ daemon : daemon
# add video if not present
sudo usermod daemon -a -G dialout
# list current groups
groups daemon
$ daemon : daemon dialout
# ^^^^^^^ now it is presentWe need to enable the serial0 device which are daemon script is expecting. Which serial device are present at boot time has been changin over time. Check for presense of /dev/serial0 with:
ls /dev/serial0 # list serial port to see if it is presentIf you see ls: /dev/serial0: No such file or directory then it is NOT present. In which case you need to enable /dev/serial0.
In order to enable /dev/serial0 we need to:
- Add lines to /boot/config.txt
So, edit the /boot/config.txt using:
# edit /boot/config.txt
sudo vi /boot/config.txtwhile in /boot/config.txt add the following lines:
# fix our serial clock freq so we can do 2Mb/s
# ref: https://github.com/ironsheep/RPi-P2D2-Support#serial-boot-time-configuration
init_uart_clock=32000000
# and condition which uart is present
enable_uart=1
# and stabilize our turbo effects (don't let turbo on/off affect uart clock)
force_turbo=1(Exit vi by entering ':', 'x', <return>)
After the file is saved then reboot your RPi. /dev/serial0 should now appear.
sudo shutdown -r now # reboot our RPiYou can choose to run this script as a systemd service or as a Sys V init script. If you are on a newer OS than Jessie or if as a system admin you are just more comfortable with Sys V init scripts then you can use the latter style.
Let's look at how to set up each of these forms:
(Heads Up We've learned the hard way that RPi's running jessie won't restart the script on reboot if setup this way, Please set up these RPi's using the init script form shown in the next section.)
Set up the script to be run as a system service as follows:
sudo ln -s /opt/P2-RPi-ioT-gateway/p2-rpi-iot-gateway.service /etc/systemd/system/p2-rpi-iot-gateway.service
sudo systemctl daemon-reload
# tell system that it can start our script at system startup during boot
sudo systemctl enable p2-rpi-iot-gateway.service
# start the script running
sudo systemctl start p2-rpi-iot-gateway.service
# check to make sure all is ok with the start up
sudo systemctl status p2-rpi-iot-gateway.serviceNOTE: Please remember to run the 'systemctl enable ...' once at first install, if you want your script to start up every time your RPi reboots!
In this form our wrapper script located in the /etc/init.d directory and is run according to symbolic links in the /etc/rc.x directories.
Set up the script to be run as a Sys V init script as follows:
sudo ln -s /opt/P2-RPi-ioT-gateway/p2-rpi-iot-gateway /etc/init.d/p2-rpi-iot-gateway
# configure system to start this script at boot time
sudo update-rc.d p2-rpi-iot-gateway defaults
# let's start the script now, too so we don't have to reboot
sudo /etc/init.d/p2-rpi-iot-gateway start
# check to make sure all is ok with the start up
sudo /etc/init.d/p2-rpi-iot-gateway statusLike most active developers, we periodically upgrade our script. Use one of the following list of update steps based upon how you are set up.
If you are setup in the systemd form, you can update to the latest we've published by following these steps:
# go to local copy of repo
cd /opt/P2-RPi-ioT-gateway
# stop the service
sudo systemctl stop p2-rpi-iot-gateway.service
# get the latest version
sudo git pull
# reload the systemd configuration (in case it changed)
sudo systemctl daemon-reload
# restart the service with your new version
sudo systemctl start p2-rpi-iot-gateway.service
# if you want, check status of the running script
systemctl status p2-rpi-iot-gateway.service
If you are setup in the Sys V init script form, you can update to the latest we've published by following these steps:
# go to local copy of repo
cd /opt/P2-RPi-ioT-gateway
# stop the service
sudo /etc/init.d/p2-rpi-iot-gateway stop
# get the latest version
sudo git pull
# restart the service with your new version
sudo /etc/init.d/p2-rpi-iot-gateway start
# if you want, check status of the running script
sudo /etc/init.d/p2-rpi-iot-gateway status
If you like my work and/or this has helped you in some way then feel free to help me out for a couple of ☕'s or 🍕 slices!
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This project is a community project not for commercial use.
This project is in no way affiliated with, authorized, maintained, sponsored or endorsed by Raspberry Pi (Trading) Ltd. or any of its affiliates or subsidiaries.
Likewise, This project is in no way affiliated with, authorized, maintained, sponsored or endorsed by Parallax Inc., dba Parallax Semiconductor or any of its affiliates or subsidiaries.
Licensed under the MIT License.
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