👩🏽‍💻 Step 2: Determining Our IP Address

Building a Self-Driving Car 👩🏽‍💻 Step 2: Determining Our IP Address

Everything connected to a WiFi network has a unique address known as an Internet Protocol (IP) address. Think of it like a mailman trying to deliver a letter. Where may he look? At your home’s address! What if you wanted to call a friend? You’d dial their unique cell phone number to get in touch!

IP addresses look like a string of four sets of numbers (ranging from 0-255) separated by periods. Look at the three IPs in the image below.

PHOTO: PC MAG

In order to remotely connect our computer to our car, we need to know the car’s IP address. There are a few different ways to do this, and one of them might work better for you than others since everyone has a slightly different router. We can start with an IP Shortcut step but if it doesn’t work for you, try the follow-up steps below. (If unsuccessful, try Plan A to get the IP of your car. If that doesn’t work, move on to Plan B).

When we need to use our car’s IP address, we can use our hostname (from the Advanced Options Step in Imaging Raspberry Pi OS) with these shortcuts instead:

hostname.local IP Shortcut

raspberrypi.local

hostname.local IP Shortcut If Using Classroom Router

YOURCARHOSTNAME.local (example robotcar1.local)

Plan A | The Ping Plan

Most of the time, you should be able to get your IP address using this method, assuming you properly went through the Raspberry Pi imager step already.

Make sure that…

Your batteries are fully charged
Your car is turned on
Your microSD card is inserted into the Raspberry Pi board on your car
Your computer is connected to WiFi you configured in the Raspberry Pi Advanced Options step

On your Chromebook, press Ctrl+Shift+T.
This will open up CROSH where we will be typing in a simple command to get our car's IP address.
Type into CROSH the following: ping -4 robotcar
Note: If you are using a classpack with a router make sure to use the hostname that you assigned your car. (eg. robotcar1, robotcar2)
This will spit out a bunch of text. To stop this simply press Ctrl+C.
Now look at the text that has been displayed and look for your IP address. It should look something like 192.168.1.155.
Note: CROSH may output a series of numbers and letters instead. If this happens you will be using that instead.
Copy your address for the next step.

If that worked, amazing! This is a tricky step. You can move on to the next page. If not, try Plan B below.

Plan B | The NMap IP Scan

Turn on car
Figure out the last 3 numbers of your network ID
MAC: Run the arp -a command to take a look at the structure of network IDs
Open Nmap and try to ping scan on your network

Plan C | The Supplicant File

If you are not seeing any IP for your Pi, go a few steps ahead in myBetabox and follow the steps for adding a supplicant file on the ‘What if I need to change my IP’ page.

Plan D | Ethernet Cable

Try connecting an ethernet cable, if you have one available, into your Raspberry Pi. Then bring your car over to your router and plug it into your router. This may allow the router to assign an IP to your car.

Troubleshooting

Ok! There could be several reasons. Try these first, and if they dont work click on the next troubleshooting guide.
-make sure your car is on
-and you are connected to the right wifi
-double check the nmap command you ran
-make sure your batteries have charge
-sometimes the IP is there, but 'Raspberry Pi' is not showing up.
- in command prompt, ping raspberrypi.local and see if anything comes up.

- turn off you car, take out your SD card and put it back in your reader. Check to see if you can still see the file. If it is still there, there is an issue with your filename or extension.

-if it is gone, that means your filename and extension were right, but something may be wrong in the file. Make another supplicant file, and make sure you have your country, network, name, and password in it correctly with no mispellings.

Now we are getting into some special cases!

- There could be an issue with your router, some routers don't automatically assign IPs to new devices that come onto the network. Google Nest WiFi Routers are one such model.

-Tell a Betabox Guide which router model you have.

-if you have an ethernet cord and have access to your router, go plug in your car to your router and try nmap again.

- Try using a different Wifi. Use a cell phone with a Wifi Hotspot, turn on the hotspot and try all the steps again.

- Try a 'head' setup. Find a computer monitor, USB keyboard, Mouse, and HDMI cable (Pi 3) or mini HDMI (Pi 4) and talk to a Betabox technician.

- If you happen to be using Ubuntu or have access to a Linux computer, message a Betabox technician about setting up a static IP

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