This is a reimplementation of an older school project, previously called Binary Digits Illuminated. The old version used an Apache server and server-side PHP scripts to interact with the GPIO pins on the Pi. But my implementation suffered from horrendous lag when multiple users tried interacting with it, so I decided to redo the whole project but this time using a Node server and Socket.IO.
More info after the install and setup section
- Not required but a tool used to SSH into the Pi would help. On Windows 10, I used tools like Git Bash or Cmder. PuTTY is another popular option
- Raspberry Pi Model 3 - haven't tested on other devices
- Raspbian OS - I used a clean install of Raspbian Stretch Full Version (2018-11-13)
- Node.JS - I used 11.2.0 installed via nvm, but you should be able to use any version that supports ES6 (ES2015) features
- Git - usually comes installed by default on most Linux operating systems like Raspbian
- 8 Lightbulbs or LEDs and a way to connect them to the GPIO interface on the Raspberry Pi board (I don't provide instructions on how to do this here, but there are plenty of tutorials online and YouTube videos to help you do it)
The project assumes you have 8 lightbulbs or LEDs connected to 8 GPIO pins on your Raspberry Pi. The exact pins I used are:
(BCM) 2, 3, 4, 14, 15, 0, 5, 6
You can change the pins in gpio.js. Additionally, you may need to configure the Gpio objects in there as well depending on your situation, you can see the onoff package on how to do that.
The order of the pins and the lightbulbs are very important. The array of pins that are hardcoded in the gpio.js file assumes that the corresponding lightbulbs are ordered the same way.
In the home directory /home/pi/ (or wherever you want), run these terminal commands:
git clone https://github.com/bvillagran/pinary-lights.gitcd pinary-lights*npm installnpm run buildnpm start
* at this point you may have to change line 48 in server.js, I recommend testing that command in the Node REPL, or to avoid that all together just hardcode your Pi's IPv4 address as a string if you know it. Your server will crash if that command fails. You also may want to make changes to gpio.js mentioned in the previous section. Hit Ctrl+C to stop the server application.
If everything is in place and your server is running properly, you can now connect to the client interface via the browser of any other device that exists on the same local network that your Raspberry Pi is connected to. To do this, type in the local IPv4 address of your Pi followed by the port number (3000).
For example, in the url bar of your browser type in: 192.168.1.128:3000 replacing the address part with your Pi's address.
Your Pi terminal should have outputted the local IPv4 address your server can be reached. But again, if it doesn't or the server crashes, check line 48 in server.js and make adjustments as needed.
npm install -g pm2pm2 startup- copy, paste, and run the command it gives you
- move into your project directory, e.g.
cd ~/pinary-lights/ pm2 start server.js- check that it's in the process list with
pm2 ls pm2 save
Your server should now be set to run on startup and every time you reboot your Pi. You may want to test it to make sure it works everytime. For more information visit the pm2 docs.
Basically, the project as a whole is meant to be used to teach the binary number system to an audience. The Node server hosted on a Raspberry Pi serves a simple client interface to devices on the same local network and establishes a two-way socket connection via Socket.IO. The client interface involves 8 buttons, each representing a binary digit or 1 byte. The buttons will change depending on the state of the GPIO pins and therefore the states of the wired lightbulbs/LEDs. Additionally, the client interface takes the binary value and converts it to decimal and hexadecimal values and changes the background to the corresponding 8-bit greyscale color.
The client and the server interact over the Socket.IO interface. When a client connects, the server will send the current state of each GPIO pin and the client interface will update to represent it. When a button is clicked or tapped, the client tells the server to switch the state of the corresponding pin, and the server will broadcast that change to all connected clients. The pin changing will also be reflected in the state of the corresponding lightbulb/LED changing from on to off or vice-versa.
This project not only serves to be an upgrade from the original, but also a learning experience for me in using Node and Socket.IO. As such, I encourage beginner to intermediate JavaScript programmers who also want to learn how to use Node on a Raspberry Pi to create cool home-automation style projects, to clone this repo and set up the project at home. I try to heavily comment my code to help guide you through it. But if you still find yourself confused, you can check out the relevant API documentation:
- Node.js
- Socket.IO Server
- Socket.IO Client
- onoff (Node GPIO package)
- serve-static (Node static file server package)
- Webpack
- If you aren't using the default Pi user, make sure that your user is added to the
gpiouser group. - Make sure you are using a version of Node that supports ES6 features.
- You may run into issues if you have multiple versions of Node installed, make sure you are using the same version throughout the whole process.
- If you find issues specifically with your GPIO pins, you can test them with the WiringPi gpio utility that usually comes preinstalled with Raspbian, or manually install it. The utility allows you to send commands to your GPIO interface through the terminal without writing a script to do it. One note I'll make here is to pass the
-gflag to your commands to make sure you are using the same numbering scheme (BCM) as the project. - I will add more things here as I find out about more issues.