Node.js en Raspberry Pi

Raspberry Pi is 'n klein, veelvuldige rekenaar.

Met Node.js kan jy wonderlike dinge met jou Raspberry Pi doen.

Wat is die Raspberry Pi?

Die Raspberry Pi is 'n klein, bekostigbare en ongelooflik bekwame, kredietkaartgrootte rekenaar.

Dit is ontwikkel deur die Raspberry Pi Foundation, en dit is dalk die veelsydigste tegnologie wat ooit geskep is.

Skepper Eben Upton se doel was om 'n laekoste-toestel te skep wat programmeringsvaardighede en hardeware-begrip sou verbeter.

As gevolg van die klein grootte en prys van die toestel, het dit die middelpunt geword van 'n wye reeks projekte deur knutselaars, vervaardigers en elektronika-entoesiaste.

Raspberry Pi en Node.js

Die Raspberry Pi het 'n ry GPIO (General Purpose input/output) penne, en dit kan gebruik word om op wonderlike maniere met die regte wêreld te kommunikeer. Hierdie handleiding sal fokus op hoe om dit met Node.js te gebruik.

Wat het ek nodig?

Vir hierdie tutoriaal benodig jy 'n Raspberry Pi. In ons voorbeelde gebruik ons ​​'n Raspberry Pi 3, maar hierdie tutoriaal behoort vir die meeste weergawes te werk.

Hardeware benodig:

• Raspberry Pi rekenaar
• MicroSD-geheuekaart (Ons beveel 'n klas 10 aan met 16 GB of hoër)
• MicroSD na SD geheue kaart adapter (gewoonlik ingesluit by die MicroSD kaart)
• Mikro-USB-kragtoevoer om die Raspberry Pi aan te dryf (2.5A of groter word aanbeveel)
• WiFi/Ethernet-kabelverbinding vir die Raspberry Pi (Nie nodig vir Raspberry Pi 3 nie aangesien dit ingeboude WiFi het)
• 'n Werkende rekenaar met internet en SD-geheuekaartleser (word gebruik om die bedryfstelsel (Bedryfstelsel) vir die Raspberry Pi op die geheuekaart te kry). In ons tutoriaal gebruik ons ​​'n Windows-rekenaar hiervoor, maar jy kan 'n Mac- of Linux-rekenaar gebruik as jy verkies
• HDMI-monitor, USB-sleutelbord (ons benodig dit net tydelik vir die eerste selflaai van die Raspberry Pi)

Vir latere hoofstukke in hierdie tutoriaal sal ons spesiale sensors of toestelle gebruik wat ons aan die Raspberry Pi koppel. Ons sal dit as spesiale vereistes in die betrokke hoofstukke spesifiseer.

Skryf Raspbian OS-beeld na MicroSD-kaart

Voordat ons ons Raspberry Pi vir enigiets kan begin gebruik, moet ons 'n bedryfstelsel installeer.

Raspbian is 'n gratis bedryfstelsel gebaseer op Debian Linux, en dit is geoptimaliseerde Raspberry Pi.

Laai die nuutste Raspbian-prent van https://www.raspberrypi.org/downloads/raspbian/ af na jou rekenaar.

Ons gebruik die "LITE" weergawe in ons tutoriaal, aangesien ons die Raspberry Pi opstel as 'n koplose bediener (ons sal daaraan koppel deur SSH, sonder dat 'n sleutelbord/skerm daaraan gekoppel is). Jy kan enige weergawe gebruik wat jy wil, maar hierdie tutoriaal is geskryf met die "LITE" weergawe as sy fokus.

Plaas die MicroSD-geheuekaart in jou rekenaar (via die SD-adapter indien nodig). Maak File Explorer oop om te verifieer dat dit in werking is.

Etcher is 'n program om beelde na geheuekaarte te flits. Laai Etcher af en installeer dit vanaf: https://etcher.io/

Begin Etcher:

Click "Select image" button and find the Raspbian zip file that you downloaded.

Click the "Select drive" button and specify the memory card as the target location.

Click the "Flash!" button to write the image to the memory card.

After Etcher is finished writing the image to the memory card, remove it from your computer.

Set up Your Raspberry Pi

To get the Raspberry Pi ready to boot we need to:

1. Insert the MicroSD memory card into the Raspberry Pi
2. Connect the USB keyboard
3. Connect the HDMI cable
4. Connect the USB Wi-Fi adapter (or Ethernet cable). Skip this step if you are using a Raspberry Pi 3
5. Connect the micro USB power supply
6. The Raspberry Pi should now be booting up

When the Raspberry Pi is finished booting up, log in using username: pi and password: raspberry

Set Up Network on the Raspberry Pi

If you will use a Ethernet cable to connect your Raspberry Pi to the internet, you can skip this step.

For this section we will assume you have a Raspberry Pi 3, with built in WiFi.

Start by scanning for wireless networks:

This will list all of the available WiFi networks. (It also confirms that your WiFi is working)

Now we need to open the wpa-supplicant file, to add the network you want to connect to:

This will open the file in the Nano editor. Add the following to the bottom of the file (change wifiName and wifiPassword with the actual network name and password):

Press "Ctrl+x" to save the code. Confirm with "y", and confirm the name with "Enter".

And reboot the Raspberry Pi:

After reboot, log in again, and confirm that the WiFi is connected and working:

If the WiFi is working propery, the information displayed should include an IP address, similar to this:

Write down that IP address, as we will use it to connect to the Raspberry Pi via SSH.

Enable SSH, Change Hostname and Password

Now your Raspberry Pi is connected to the internet, it is time to enable SSH.

SSH allows you up use the Raspberry Pi without having a monitor and keyboard connected to it.

(You will need a SSH client for this on your non-Raspberry Pi computer. We use PuTTY for windows)

Open the Raspberry Pi Software Configuration Tool:

You should see a menu like this:

Select option 5 Interfacing Options:

Select option P2 SSH, to activate SSH:

Confirm with YES, to activate SSH:

SSH is now enabled, and you should be in the main menu again.

Select 1 Change User Password, and follow the instructions to change the password. Choose a secure password, but something you will remember:

After you have finished changing the password, you should be back in the main menu.

Select 2 Hostname, and follow the instructions to change the hostname:

After you have finished changing the hostname, you should be back in the main menu.

Now we will close the menu and save the changes:

When selecting Finish, you will get the option to reboot. Select Yes to reboot the Raspberry Pi.

You can now unplug the monitor and keyboard from the Raspberry Pi, and we can log in using out SSH client.

Open PuTTY, type in the IP address for your Raspberry Pi, and click Open:

Log in using the username pi and the new password you specified.

You should now see a command line like this: (we used w3demopi as our hostname)

You are now able to run your Raspberry Pi in "Headless-mode", meaning you do not need a monitor or keyboard. And if you have a WiFi connection, you do not need a ethernet cable either, just the power cable!

Install Node.js on Raspberry Pi

With the Raspberry Pi properly set up, login in via SSH, and update your Raspberry Pi system packages to their latest versions.

Update your system package list:

Upgrade all your installed packages to their latest version:

To download and install newest version of Node.js, use the following command:

Now install it by running:

Check that the installation was successful, and the version number of Node.js with:

Get Started with Raspberry Pi and Node.js

Now you have a Raspberry Pi with Node.js installed!

If you want to learn more about Node.js, follow our tutorial: https://www.w3schools.com/nodejs/

In the next chapter we will get to know the GPIO and how to use it with Node.js.