Node-PI, PI.js

Install NodeJS on the Raspberry Pi.

Sample scripts for NodeJS on the Raspberry PI

This project is gathering scripts based on several nodejs modules: serialport, onoff and i2c-bus

---

Attention! : The nodejs modules used here seem to require the ARMv7 instruction set. To visualize that, on your RPi, type at the command prompt:

 $> uname -a
 Linux raspberrypi3 4.4.11-v7+ #888 SMP Mon May 23 20:10:33 BST 2016 armv7l GNU/Linux

I was not able to have the projects featured here working properly on Raspberry PI A or Zero, unlike the Java counterpart of this project...

---

Note : Some demos are using the websocket module, installed as well during the npm install mentioned below. This is only for the demos to work, this module is not mandatory for the interaction with the sensors and other devices.

The goal here is to provide a JavaScript access to sensors, PCBs and other devices hooked up on a Raspberry PI, like the code of this project is doing for Java and other JVM-aware languages.

Note
The Internet Of Things (IoT) is extensively using services (REST services are among the most popular). NodeJS provides all kind of modules, many of them will allow you to talk REST fluently. Bridging sensor data with an IoT server becomes a piece of cake. See the Swagger directory of this project for more details.

First installation

We assume you have already installed NodeJS and its npm companion on the Raspberry PI.

This can be done this way on teh Raspberry Pi:

$ curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
$ sudo apt-get install -y nodejs
$ sudo apt-get install gcc g++ make

You may also need

$ npm install node-gyp
$ npm install libxmljs

Note: To upgrade your existing installation:

 $ [sudo] npm install -g npm 
 $ [sudo] npm install nodejs-latest

 $ node -v
 v10.23.0
 $ npm -v
 6.14.8

Note: I had trouble with recent versions of nodeJS (17.x).
Using nvm to install the version below fixed the issues.

After cloning this repository on the RaspberryPI, run the following command from the root directory of the project (the one containing package.json):

 $ npm install [--registry=https://registry.npmjs.org]
 $ npm install serialport --unsafe-perm --build-from-source --registry=https://registry.npmjs.org
 $ npm install [-g] [--unsafe-perm] [--registry=https://registry.npmjs.org]

This will install the required nodejs modules.

See the available tasks from npm:

 $ npm run

Execute one of them:

 $ npm run test

...etc.

Simple GPIO interaction

This can be used to drive an led, a relay, etc. See the source in switch.js. To run a test script:

 $ node testSwitch.js
 Ctrl+C to stop
 Switch on pin: 18
 Switching off
 Switching on
 Switching off
 Switching on
 Switching off
 Switching on
 Switching off
 Switching on
 ...

This will turn the pin (#26, GPIO_07 in the testSwitch.js code) on and off, every second, for 100 seconds (one minute and forty seconds). The wiring corresponding to the code is done as follow:

MCP3008. Analog to Digital Converter with SPI interface.

The source is in mcp3008.js. To run a test script:

 $> node testMcp3008.js
 Usage: node /home/pi/node.pi/testMcp3008.js [debug]
 Ctrl+C to stop
 Reading MCP3008: CLK: 18 MISO: 23 MOSI: 24 CS: 25
 Val:599
 Val:600
 Val:601
 Val:601
 Val:600
 Val:600
 Val:815
 Val:967
 Val:972
 ...

The pin numbers are always something, depending on the framework you are using (PI4J, WiringPI, onoff, etc). The wiring corresponding to the code is that one:

I2C BME280 (Pressure, Humidity, Temperature, Altitude)

The source is in bme280.js. To run a test script:

 $> sudo node testBme280.js
 Init...
 Temperature : 22.21°C
 Humidity    : 61.11 %
 Pressure    : 1017.17 hPa
 --------------------------------
 Temperature : 22.21°C
 Humidity    : 61.11 %
 Pressure    : 1017.15 hPa
 --------------------------------
 Temperature : 22.21°C
 Humidity    : 61.10 %
 Pressure    : 1017.17 hPa
 --------------------------------
 ...

Note: The BME280 provides I2C and SPI accesses. Here we use I2C. Make sure you connect the BME280's SCK to the Raspberry's SCL (like pin #5), and the BME280's SDI to the Raspberry's SDA (like pin #3).

All the I2C devices are wired the same, and can co-exist in the same circuit. They all need a ground GND, a hot wire (VIN or 3V0), a clock CLK and data SDA. The distinction between the devices is made at the software level, with the address of the device on the I2C bus.

Here is the way to wire both the BME280 and the L3GD20.

Read GPS data, through a Serial port

Just the parser

$ node testNMEAParser.js

With a real GPS

See the code in SerialReader.js and NMEAParser.js. To run a test script:

 $> sudo node testGPS.js
  To stop: Ctrl-C, or enter "quit" + [return] here in the console
  Usage: node /home/pi/node.pi/testGPS.js [raw]|fmt
  Serial /dev/ttyUSB0 br 4800
  Port open
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPRMC,013948.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*78
  $GPRMC,013948.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*78
  $GPRMC,013948.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*78
  $GPGGA,013949.158,3744.9324,N,12230.4161,W,1,06,1.5,-21.4,M,,,,0000*07
  $GPGGA,013949.158,3744.9324,N,12230.4161,W,1,06,1.5,-21.4,M,,,,0000*07
  $GPGGA,013949.158,3744.9324,N,12230.4161,W,1,06,1.5,-21.4,M,,,,0000*07
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPRMC,013949.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*79
  $GPRMC,013949.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*79
  $GPRMC,013949.158,A,3744.9324,N,12230.4161,W,000.0,102.9,130816,,,A*79
  $GPGGA,013950.158,3744.9325,N,12230.4161,W,1,06,1.5,-21.5,M,,,,0000*0F
  $GPGGA,013950.158,3744.9325,N,12230.4161,W,1,06,1.5,-21.5,M,,,,0000*0F
  $GPGGA,013950.158,3744.9325,N,12230.4161,W,1,06,1.5,-21.5,M,,,,0000*0F
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSA,A,3,20,21,15,13,10,29,,,,,,,2.3,1.5,1.8*33
  $GPGSV,3,1,12,20,24,056,34,21,64,070,33,15,33,055,35,13,08,036,16*74
  $GPGSV,3,1,12,20,24,056,34,21,64,070,33,15,33,055,35,13,08,036,16*74
  ...

or

 $> sudo node testGPS.js fmt
 To stop: Ctrl-C, or enter "quit" + [return] her ein the console
 Usage: node /home/pi/node.pi/testGPS.js [raw]|fmt
 Serial /dev/ttyUSB0 br 4800
 Port open
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:45 GMT+0000 (UTC)
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:45 GMT+0000 (UTC)
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:45 GMT+0000 (UTC)
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:46 GMT+0000 (UTC)
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:46 GMT+0000 (UTC)
 Position: { lat: 37.748895, lon: -122.506955 }
 Time: Sat Aug 13 2016 01:45:46 GMT+0000 (UTC)
 ...

I2C L3GD20 (Gyroscope)

See the code in l3gd20.js. To run a test script:

 $> sudo node testL3gd20.js
    To stop: Ctrl-C
    Usage: node /home/pi/node.pi/testL3gd20.js [verbose]
    Init...
    Starting...
    Calibrating X, please do not move the sensor...
    Calibrating Y, please do not move the sensor...
    Calibrating Z, please do not move the sensor...
    >> X:0 Y:0 Z:0
    >> X:0 Y:0.7393750000000003 Z:-10.399375000000001
    >> X:-0.6216874999999997 Y:3.5393750000000006 Z:-59.189375000000005
    >> X:0 Y:0 Z:-6.383125000000001
    >> X:0.19206250000000002 Y:-1.3256249999999996 Z:8.220625
    >> X:-0.2891874999999997 Y:0 Z:0
    >> X:0 Y:-0.3368749999999996 Z:0
    >> X:-0.3154374999999998 Y:-0.22312499999999957 Z:0
    >> X:0 Y:-0.17937499999999984 Z:0
    >> X:-0.15793750000000006 Y:0 Z:0
    >> X:0.12206250000000018 Y:0.32812500000000044 Z:0
    >> X:0.1483125000000003 Y:0.4506250000000005 Z:0
    >> X:-0.4991875000000001 Y:0.5381250000000004 Z:-18.388125000000002
    >> X:-0.48168750000000005 Y:1.8068750000000007 Z:-33.306875000000005
    >> X:-0.5079374999999997 Y:2.314375000000001 Z:-35.98437500000001
    >> X:-0.6391874999999998 Y:4.633125000000001 Z:-74.904375
    >> X:3.6745625000000004 Y:6.418125000000002 Z:-97.72437500000001
    >> X:-1.0504375000000001 Y:4.886875000000001 Z:-76.313125
    >> X:-0.4904375000000001 Y:3.4868750000000004 Z:-51.760625000000005
    >> X:-0.2279374999999999 Y:1.7718750000000005 Z:-41.426875
    >> X:-0.1754374999999997 Y:4.213125000000001 Z:-67.274375
    >> X:3.7095625000000005 Y:4.554375000000001 Z:-71.150625
    >> X:4.1033125 Y:4.493125000000001 Z:-77.091875
    >> X:3.5433125000000003 Y:2.1831250000000004 Z:-49.39812500000001
    >> X:6.308312500000001 Y:2.349375 Z:-78.544375
    >> X:6.387062500000001 Y:2.751875000000001 Z:-97.356875
    >> X:6.868312500000001 Y:1.2993750000000004 Z:-80.058125
    >> X:-1.8904375 Y:3.670625000000001 Z:-27.706875000000004
    >> X:-4.217937500000001 Y:5.718125000000001 Z:-29.885625000000005
    >> X:-0.8754375000000003 Y:1.8943750000000001 Z:-36.010625000000005
    >> X:-7.936687500000001 Y:2.988125000000001 Z:19.770625000000003
    >> X:-3.3954375 Y:-6.024375 Z:67.43187500000002
    >> X:0.7170625000000004 Y:-7.958125000000001 Z:78.77187500000001
    >> X:0.5858125000000003 Y:-4.974375 Z:62.16437500000001
    >> X:-0.1404375 Y:0 Z:0
 ...

Demos

Some demos are available. As nodejs can also be used as an HTTP Server, they will display the sensors' data in a graphical Web UI.

GPS demo

Plug a GPS in one of the USB ports, and check its name (like /dev/ttyUSB0). If needed, modify in gps.demo.js the line that says

 var serialPort = '/dev/ttyUSB0'; 

Then start the server:

 $> sudo node demo.gps.js

And load the URL displayed in the console in a WebSocket-enable browser (like http://localhost:9876/data/demos/gps.demo.html.

Note: This one would run on any OS (Windows, Linux, Mac,...) as it does not require any GPIO pin. All you need is a USB port.

Gyroscope demo

Start the server:

 $> sudo node demo.gyro.js

And load the URL displayed in the console in a WebSocket-enable browser.

ADC (MCP3008) demo

Start the server:

 $> node demo.adc.js

And load the URL displayed in the console in a WebSocket-enable browser.

IoT demo

Requires an Adafruit-IO account. Will feed 4 feeds:

• onoff, a switch
• atm-press, a gauge [980, 1050]
• air-temperature, a gauge [-10, 60]
• humidity, a gauge [0 - 100]

Connect the BME280 on the Raspberry PI, and the led (switch demo) asabove. Start on the Raspberry PI:

 $> sudo node demo.iot.js <Your-Adafruit-IO-key>

Then you can launch iot.one.html in your browser. Provide your Adafruit-IO key in the UI when prompted, and you can see the sensors data on the page. You can also turn the switch on and off from the same page. You can also deal with the switch from a Pebble (a smart watch), as described here, in the REST.app directory.

To come...

• PWM
• FONA
• Servo HAT
• Sense HAT
• ... and more

To debug a nodejs application:

OK, console.log is great, but there are other ways to debug...

To do once:

$> [sudo] npm install -g node-inspector

Then

$> node-debug testUtils.js
Node Inspector v0.12.8
Visit http://127.0.0.1:8080/?port=5858 to start debugging.
Debugging `testUtils.js`

Debugger listening on port 5858

Then open Chrome, and load the URL above. Switch to the "Sources" tab (if it is not visible yet), set your breakpoints, and start debugging!

More recently

See https://nodejs.org/en/docs/inspector

From on terminal

$ node --inspect server.js

From a Chrome browser:

chrome://inspect

... and follow the instructions.
Then from another browser, reach the URL served by the node server, like http://localhost:8888/leaflet.tide.stations.html, and you can set breakpoints in the server's code.