Fing: a Tool to Find What’s on Your Network

Fing: a Tool to Find What’s on Your Network

FING and how to use it

Raspbian for Robots is simple to set up when you have a straightforward home network, and one Dex robot. But life isn’t always simple and that’s when Fing can is useful to find Your Raspberry Pi IP Address.

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In cases where for some reason or another, you do not meet with success when trying to ping dex.local, you can attempt to reach your robot via its IP address (usually a number like 192.168.x.x where each x may be a number between 0 and 255). The challenge here is in determining what IP to use (the value of those two trailing x).  This tutorial will help you walk through finding your Raspberry Pi IP Address on a local network.

Fing is not a Dexter Industries product, but rather one that we recommend. You can download it from their site and please do read their Terms of Use beforehand. We recommend that you download their software onto a phone or a tablet, it’s handy to have it in your back pocket, especially if you’re running a camp or a class.

Fing will list all devices on your network, including hostname and IP.  If your robot was assigned an IP, Fing will list it. If Fing doesn’t find it, then your robot is not on the network, and the issue is either in setting up the Wifi information or a power issue with the robot.  Either way, Fing should be useful to help you find your Raspberry Pi IP address.

Connecting to Your Wifi

Regardless of the device you choose to use for Fing,  you first have to connect this device to the same Wifi network as your Dex robot and your laptop.

Your robot, your laptop, and your Fing device are meant to be all on the same network. If you have a dual band router at home, it is best if they are on the same band (most likely the 2.4Ghz one). Once your Fing device is on the same network, you can launch Fing.

dexnet

Setting cell phone to ‘dexnet’ wifi network

dex_dexnet

Dex previously configured on dexnet

Figuring Out What's On Your Network

Fing will not tell us everything, but it’s a tool that will give you a piece of the puzzle and help Find Your Raspberry Pi IP Address. Right at launch, it will start scanning and list every device that is currently connected. And maybe even some that the network remembers from a previous connect that may not be running right now.

Of particular interest is the IP number next to each device. Sometimes, trying to reach dex.local (or dex1.local, or dex2.local…) doesn’t work. When you’re in the middle of something, you don’t want to start debugging this right away. You can just use the IP address found here instead of dex.local.

 

On Android, the status of each device is color-coded.  Dark yellow is the device where Fing is running on. Bright yellow are all the devices on the network, and greyed out are the devices that are still in the router’s memory, but are not currently up. Icons give you an idea of what’s what. The router has a wifi icon, cell phones and tablets have a mobile screen icon, computers of all types have a squiggly network icon.

The left column gives you each device’s IP address, with its MAC address underneath. Generally speaking, we will not do anything with the MAC address, so you can ignore that information.

The right column gives you the hostname, and the company that manufactured the Wifi dongle. If you happen to have two devices with the same hostname, you may be able to tell them apart via their dongle manufacturer (if they have different dongles, that is). We don’t recommend to ever have two devices with the same hostname, but errors happen and that’s why there’s Fing.

 

On Ios, you get similar informations. The first column is filled with icons. Your own device has an icon marked “You”, the router has a Wifi icon, and other devices have a little network of nodes icon.

The second column is a list of the assigned IPs, followed in the third column by hostnames, the one that’s left blank is an Android phone, they are notorious about not sharing their hostname properly.

Fourth column is the manufacturer of the Wifi connector. It can be useful to differentiate two devices sharing the same hostname by mistake. We don’t recommend having two robots with the same hostname, but Fing will give you a way out of the conflict by making the IPs of each device visible.

The last column is where MAC addresses are listed. We will not be doing anything with that information.

 

Complex Networks

In camp situations, or in schools, you may have to handle a complex network. In those cases, it may happen that Fing will hide devices from you. Fing still finds them, but will add a number in parenthesis after the IP address to indicate that many devices are grouped together.

Find Your Raspberry Pi IP Address with Fing

This implies that there are three devices hidden away behind this IP. Possibilities are that those devices are on another band (2.4GHz, while you’re on 5 GHz), or they’re connected to a different router, even though the routers talk to each other and exchange information.  Multiple routers work seamlessly most of the time, but not always.  If you “click” or “touch” this entry, you will be taken to a second screen, where all IPs will be listed under “More IP Addresses”.  Unfortunately, you are not given the hostname to go with each of those IPs, so this is of limited help.

Fing with complex network 2 Find Your Raspberry Pi IP Address

Should you have such a situation, the best way is to make sure that both laptop, cell phone with Fing, and Dex robot are on the same router. Fing will then list them properly, and networking will be easier for everyone.

What If Fing Never Displays My Robot?

If Fing never displays any information about your robot, you know for sure that your robot hasn’t connected to your Wifi. You will have to get the Ethernet cable out, and look at the Wifi setup.

If you can, plug the Ethernet cable right into the router. Fing should find it then, and tell you which IP to use. In most cases though, this is not easy to do and you’ll have to plug the Ethernet cable into the port on your laptop.  Either way, you will have to look at the wifi setup on dex.

If you need to review the steps to set up the Wifi, we have written instructions for GoPigo. They are valid for all our products using Raspbian for Robots.

What If Fing Never Displays My Robot?

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