hackmas2026 - What is Meshtastic?

[applause] >> Thank you very much. Thank you all for coming to this presentation. I hope it's fine for everyone to give the talk in English. There are just so many English words that I don't have a proper translation to German. So, I stay with English. Um first a few words about me. My name is Christian. I'm uh in my daily life a computer vision researcher um slash software developer working on computer vision and machine learning for robotics. In my free time, I like to play music and given I'm a middle-aged man, also riding my bike. Um but I'm also into retrocomputing, gaming consoles, uh and also cameras. So, you can also talk to me about uh the Game Boy camera or floppy-based cameras afterwards if you are into that. Um social media I'm basically now down to Mastodon uh and this is the link to my profile in Graz social. So, if you look at this, I'm probably not a person that is um that can tell you much new things about MeshTastic, but I still want to tell you what I learned about in the past half year after falling in the rabbit hole after watching this uh Arte documentation uh Arte Tracks Off Grids where they have a following um a few groups of people building mesh networks for their communities. So, on the one hand um internet services uh to rural areas, but also um off-grid communication with Laura um in regions where infrastructure has been taken down by um by uh emergencies, but also by uh either during protests by by the government, so they could still continue come with communication. So, that brings me to the core. What is Meshtastic? It is an open source off-grid decentralized mesh protocol. So, that means that every participant in the network is also part of the infrastructure and there's no dependency on dedicated cell towers or other infrastructure. We will hear later later that it's this is not entirely true, but this is like of the like the concept. It runs on very low power devices. I brought a few here, so this is one that you can buy commercially. It's basically um the Meshtastic node plus some battery, so it can operate um for multiple days with in this case a Nokia 3310 battery. Um it supports encrypted messaging, so you can send messages to channels, but also direct messages between individual nodes. Um and if you think about it, it's not an internet replacement. It's very low bandwidth, so it's in the kilobit range from 1 to about 20 or 30 kilobits. So, it's not aiming to be a replacement for your um normal internet access, but really to communicate in text form. Taking another step back, what is a mesh? So, this is the Wikipedia um definition. It's in a net in a networking topology is it is where nodes are communicating connected directly and non-hierarchically dynamically and they cooperate to route data. So, what this means is that every participant in the network is at same. They send and receive messages, but uh they're also responsible for forwarding messages um in case they are not the recipient. And in the case of Meshtastic, the individual connections are non-reliable wireless um communications. Uh and if you if you show it in a graph like like this, you typically show it in a undirected graph where the nodes are the participants and the edges are the connections between them. So, typically it's not fully connected, so only uh each node can only see a bunch of their neighbors. So, what does it look like in the Meshtastic setting? Um so, you have a bunch of clients that are loosely connected and they exchange data. Um you can see here a slight sle- uh sneak peek that not all clients are the same, so you can have some that are routers that are uh helpful to make the area of the network bigger. And uh at the client, you typically connect to a client like this um with your phone or with your uh laptop um to send and receive the actual messages. So, with that uh um I want to shortly talk about the routing protocol that is being used by Meshtastic. Um it's called managed flooding. And so, uh if you want to send a broadcast and that means that all of the nodes that have the same settings as you uh should receive the message. So, in this case, um the node zero wants to send a broadcast um and it can directly see nodes one and two. Um so, at time zero, it sends the message um and each message has a so-called hop limit, which can start, let's say with three. So, you say, um this message is at most to be repeated three times. And if if if a node receives a message with a higher hop count or hop count of zero, it will stop forwarding the message. Okay, so at at time zero, the message is sent and it's being received by the nodes one and two. Um because of the way the wireless uh communication works, when a node receives something, it has to wait before it's allowed to send again. And the time is randomized, so not everyone who just received something tries to send at the same time. And in the case of Mesh Testick, there's also a scaling by the signal-to-noise ratio. So, in this setting, uh node number one has a better reception than node number two. So, node number two gets to answer first. And the idea is that you um that nodes that are further away have a lower signal-to-noise ratio, so they should be the ones that forward the message, so you can extend the actual um reach of your network. So, at time one, now uh node number two repeats the message, uh and reduces the hop count to two. And node number three um receives it. Um and basically acknowledges uh the the reception. And in this network, we have just three nodes, so um the routing stops here. So, as you can imagine, that's quite uh inefficient if you have a lot of nodes, because as the name implies, um messages are being flooded out uh in a in a very rapidly. So, that's the reason also why Mesh Testick only supports a hop count of up to seven, so you can basically contain your messages to a local network. However, um for direct messages, you can do a bit better with this. Um so you start with managed flooding. In this example, node number A wants to send the message to D. Um but it only has uh the nodes B and E in its vicinity, so it sends the message out. Both of the nodes repeat the message. Um E doesn't reach the node, so the message eventually dies off. But the node number B um can relay the message to to D, which acknowledges the the receipt. So um uh B knows that a message has been delivered, so it can stop sending it. And it can, in the second step, remember that it has a direct connection to the hop uh to to D. Um and it will forward the acknowledgement back to the to the sender A, and so sender A can now um see that the next hop to D is B, so it will store this in its database. And if the next time you send a message, uh you don't have to broadcast it anymore, so you can direct A can directly send it to B, who knows to send directly send it to D. Um this works if the network is stable and the connections are the same. But uh as it is with these uh wireless networks, you cannot rely on that. So in case the direct next hop routing doesn't work, it falls back to the flooding, and in this way kind of um discovers the topology again. Right, so now we can send messages between nodes. Um and I hinted at this in the beginning that not all nodes are the same. So Meshtastic um defines a set of, um, uh, they they call it, uh, device roles. Where your default is, um, a client. So, that's basically something you maybe have at home at the, uh, on your desk. Um, uh, maybe a good antenna connected to it. Um, or if you are out out and about, um, and, uh, just want to send and receive messages and there's no infrastructure, that's a good default role because it forwards messages from other nodes and it allows you to send and receive messages. Um, client mute is a variation of that. So, it's has the same functions as client, but it doesn't forward messages. That can make sense if you have, if you're like me and have like five nodes on you, they don't need to repeat the message all over again. So, you can send them to set them to client mute. They will still be able to send and to receive, but they're not participating in the, in the routing of messages. Um, especially for, for those battery-powered nodes, it might also make a difference in battery life because, uh, most of the time you're not sending or receiving, but you are forwarding messages for the network. So, it typically runs about twice as long when you switch it to the mute, uh, role. Accompanying the client mute is, uh, client base. Um, it's also like client, but it has, um, so-called zero-hop forwards. That means, um, a client base is probably a node that you put on top of your roof with a good antenna, a good connection, um, and then you have, uh, a lot of client mutes in the house or with you, um, and there's a nice feature if they favorite, um, themselves, um, the first hop doesn't count. So, you can send the message from your local node, but only the first hop after the base station will count as hop number one. So, that also allows you to reach fast further. Um and there's another one which is uh called a router or rooter, you strategically placed that um on a very high location. And yeah, so this is the graphic from from the Meshtastic page. It's not meant to go on a on your house. It's really meant like there's a cell tower on top of this mountain. So, uh for instance, uh in my hometown of Graz, we do have one router that is on the uh Schöckl, which is the the highest mountain in the vicinity, and it has a good coverage of of the whole uh city. So, it's typically enough to have one of those routers in in a larger network. Um there are also other types uh like sensor and tracker, so you cannot only send messages, but you can also send telemetry data, which can be um sensor data from your home automation, uh but you can also send uh GPS locations to each other, uh and then you would choose one of those roles because they they um prefer to send those messages instead of uh uh text messages. So, one thing that's missing is I didn't talk about the actual uh communication protocol. Um the Meshtastic is using LoRa or long range. Um that it's um it's using uh chirp spread spectrum modulation. So, if you look at at the spectrogram of a uh transmission, it looks like this. So, if in your frequency band, you have up and down chirps, and they determine um the symbol that's being sent. Uh you can set different spread factors, so how many number of bits you want to encode in a symbol. The more you put in, the the more signal to noise ratio you need to actually um uh deliver the message. So, you can set a lot of parameters um which allow you to go between maximum transmission length and maximum bandwidth. In the EU, um it's using 868 or 433 MHz, which is this uh license-free um bands. I think it's typically used by things like car garage door openers um and wireless sensors. Uh so, in the EU, it's special that you have a 10% duty cycle. So, in an hour, yeah, each node can only occupy the channel for 10% of the time. If it exceeds that, it needs to wait for the next hour and then uh can do it again. Um so, the default setting that uh comes with meshtastic allows for about 1 kilobit per second, but you can tune it between 0.1 and 21 kilobits, depending on your needs of uh of range. And there's a nice Easter egg in the spectrogram. So, the meshtastic logo is actually the end of the header in the Laura message. Uh well, yeah. So, one Laura message message to give you an idea is about 230 bytes of usable data. So, that's what you can send with one packet. So, what is a node? Um no matter what kind of node it is, it always has the same components. It has a Laura uh radio module. Um it has also a microcontroller to actually run the firmware to do the routing. Um some you need some kind of power supply and uh optional inputs and outputs to actually uh do do messaging, but you can also just connect uh GPS uh antennas or sensors and turn it into a sensor a In the meantime, there's quite a lot of them that are available. So, there are those um development board kind of things, which are basically just the Laura radio and uh the microcontroller, flash the firmware on it, connect it to your PC, and you have a node. Um there are ones that are they call it tracker. So, it's basically in a credit card shape. You can put it uh on a lanyard uh or in actual purse. Um also doesn't have any input and output and solely relies on connecting uh maybe your phone to it to interact with the device. But then there are also some Blackberry-style devices, which are self-contained, so that they basically have um uh means to input and output messages. So, you can just hand this to someone and um have them be part of the uh of the network. And this picture on the right is um a solar-powered node. So, this is the one that I put on my uh rooftop. Um it's basically self-sufficient, so you have a solar uh panel, batteries. The batteries will power it for 2 weeks if there's absolutely no sun, um and otherwise it's being constantly charged up by by the solar panels. You can attach whatever antenna you want to it to um going into the into the antenna uh chapter is a whole rabbit hole, which I'm not going to do today. Okay, um so if this works, I have my phone here, and I can show you how this looks like in the Meshtastic app. If I can get it on the second screen. >> [snorts] >> Yeah. >> So, whenever you configure um Meshtastic, uh you the first thing you will see is that there's a default channel, which has the name of uh of the settings that you chose in in the setup. And it's basically um it's unencrypted, and it's like a group chat of people that are close to you. Um in this case, it's yeah, a lot of things have been posted in the last few days here. So, there's actually, I think I saw last time around 10 active nodes here. So, this is what you see. Uh it tells you about uh which nodes are in your vicinity. Um if they are directly connected, you get these good and medium um signal bars. Um so, there are there's one in the in the in the bottom, which has uh there's a little two. So, it uh two two hops to get to this um to this node. So, what you can do is you can receive messages from the audience. Um uh you can send messages uh to a group chat. Um there can be in total, you can define eight chats. So, you can you will notice some have a green lock, and others have the orange lock. So, you can define the uh a shared um key. So, only people who know that key can also receive the message. But, you can also uh individually send messages to to other nodes um that you maybe know from before. Uh additionally, if nodes are sharing their location, uh you will get this here on on the map display by default location is not shared on the public channel but you can choose to share it on your private channel so if you are a group of people you can share location with each other and no one else will see it. Yes, I think that's all I want to show for this. Okay. Yeah, so I already hinted that it's what are applications. The main thing it was designed for is off-grid text communication. As I said the the the reason for in first for not having infrastructure can be many so you can be in an emergency, you can be hiking out in an area where there just is no cell reception. I saw some fun example where people didn't want to pay for the Wi-Fi on cruise ships so instead they spent the money on mesh tactic notes and gave it to everyone in the family and they were happily texting each other without having to pay the cruise ship provider. Um Yeah, fun and and maybe also not so fun things because people also using it when for protests governments decide to switch off communication networks. Um yeah, so it's of course possible to communicate there as well. You can use it as a sensor network. It has MQTT up links so you can include it into your home assist home assistant if you if you're using that. Um Yeah, as I already said people and animal tracking not for nefarious things but for actually useful applications. Um I saw use cases where farmers put trackers like this on their cows on a large property they have and they where they couldn't rely on things like air tags because they need other Apple phones to play the infrastructure. Uh and basically whatever you can think about and but it shouldn't need too much bandwidth. More than a few kilobits uh is probably already too much. Okay, I told a bit about the encryption um since a few software versions there is uh um appreciate keys on public channels with AES 256. That means uh you're responsible for uh exchanging the key beforehand. If you have that um you can communicate in an encrypted way. For um direct messages, there's a public private key um feature. So, when a node announces itself, it sends out also sends out its public key. So, only it can uh decrypt uh receiving messages with its private key. Due to the low bandwidth, um it's not going to be so secure as let's say Signal. So, there are just some compromises that had to be made to fit the messages into the 200 byte and still have a usable payload. Um so, the devices themselves they will just happily pair with everything that that is next to it. So, um if you come with a phone and want to pair with it and it's not currently paired or uh to another phone, it will do that and by that way leak all of your keys that are stored on it. Um it's uh it also doesn't have perfect forward security. So, you can um um yeah, receive all of the messages that you see, store them for later, and whenever you find the key, you can decrypt the data later. And um at the moment there's no authentication. So, you're basically trusting the other devices on first use. Uh as I said, no integrity check, but it's not entirely true. So, you can detect if a private key, for instance, uh or a public key changes for one node. Um then you can ask that person or connect contact that person a different way and see if they just refreshed the node or if something else is going on. The firmware itself is quite nice. So, it's extensible via modules. Uh there are a few that are that are there by default, like telemetry that allows you to set that you want to set send sensor sensor information like temperature, humidity. Um there's support for a lot of sensors that you can buy with I squared C. There's a feature which is called detection sensor. So, you have a GPIO input and whenever this detects higher or low, you send a message to the mesh. So, you could think you can uh do this with your doorbell. When someone is at your doorbell, you can send a message. Uh MQTT, so you can forward message data to and from um the internet to bridge larger gaps between networks. Um there are canned messages. So, nodes like this, they have a display and a joystick, but it it's not really fun to write messages. So, you can define some and then just send them. There's a range test where you have your node at home and you take this with you and and just drive off and see how far you can still receive messages. Then there's a new feature which is called mesh beacon. This is interesting if you have non-standard settings for your network. So, you can put a node somewhere which announces every 3 hours how new people could could reach your um local mesh. And finally, something very interesting is serial. So, this allows you to control uh a node via yeah, um UART. And so, you don't need Bluetooth or USB. You can directly go to serial. And I had a bit of fun with that uh, prior to the Congress. So, uh, I wanted to use that to connect Meshtastic to a retro computer. But, when I searched for the for old computers on the hardware, I actually found this typewriter. And learned that it has a serial port, um, from from the beginning. So, it's meant to be like a teletype, um, uh, from 1984. So, I got it quite cheap because two buttons didn't work, but this was easy to fix. Um, and the rest that was remains, uh, remaining to do is, uh, connect the um, a Heltec V3, which is one of those commercially available nodes, um, with a level shifter to the uh, RS-232 um, interface. Fortunately, I I I remember you need a level shifter because RS-232 is plus minus 15 volts and the ESPs have three volts. Unfortunately, I only remember this after killing my first node because, um, yeah. It's, uh, I think I used it at in school last time, so um, something I could fix with money in this case. Um, and it was a good opportunity for me to get to know the firmware a bit better. There were a few annoying things in the in the, uh, firmware. So, the typewriter wants to see carriage return feed in the correct order, otherwise weird stuff happens. And the Android app doesn't care about that, so there's some text replacement that I added to the serial module. Um, also, if you send emojis, they are not rendered or not shown, so it replaces them with the name of the emoji, um, when you before it prints it out. Um, yeah. And basically, that's, uh, a demo that was running here outside of the of the room for for the past days. And I think it went well. People figured out how to use it. Um there was the first profanity written on it was only 2 hours in after switching it on. I expected this to be much earlier, but you're very good people here. Um yeah, so this is a bit of a fun project I did. Um so yeah, of course you can send uh I'm not sure if you can see it ASCII ASCII arts to it. Uh was only misused it a bit. So now, if you want to get started, what what you what do you want to do? The main rule is uh to order two nodes because two is a mesh and you cannot be sure that other people around you will be able to receive you or you will see something, but if you have two, you can at least start playing with it. Uh while you wait, uh read this great documentation on uh meshtastic.org, which uh uh basically tells you everything that uh I told you uh today. Um always flash the newest firmware. There's a lot of development going on. It's a very active project. Um when you switch it on for the first time, it will ask you where you are. This is important to have the correct uh Laura settings and to be actually in a in a in a band which is license-free. Um there's some presets to select. Uh typically it's called uh long fast, which is like the default. Um many uh meshtastics in Austria using that. Um sometimes medium fast. So the problem starts to if you have more than 120 active nodes or 150 active nodes, messages take so long that you block each other in in the long fast settings, which is why people are switching to medium fast in that uh in those settings. And yeah, just write something to the default channel and see what happens. What's next for Meshtastic? At the moment, the 2.8 firmware is in beta testing. They stress tested it at Def Con conference with a few hundred nodes successfully. So, we will maybe see it soon. It has some new presets for larger messages, especially for the US because there you have a larger frequency band that you can use. But also in the EU, there are new presets that should work well for um if you have reliability issues above said 120 nodes. It also has packet packet signing with elliptic curve cryptography. Um at least for short messages because you for the signing itself, you need additional bandwidth. But if you just send short messages, you can also get like a little tick mark in the app that will show you that the package origin from the correct node. And what we will see is more and more of those commercial nodes. Um and but nothing stops you of buying those things separately and basically building your own device. Um that's all I have. Thank you for your attention. >> [applause] [applause] >> Um two small additions. One for the getting started. I don't know how it's in Austria, but in Germany, don't get a 400 MHz one because it's quite dead. Get an 800 one. You'll do yourself a favor. >> [gasps] >> And one another thing, you often you talk always about commercial devices. Um you can't get it completely commercial free because the Laura chip itself has to be licensed. So, at least this has to be from a commercial provider. >> That is correct and I think at the moment there are just one or two actual companies that are making those chips. Um, so the hardware cannot be completely open source. Uh, you will always be relying on some um, piece in your hardware stack which is the Laura radio. And more more often it's also the microcontroller ESP or Nordic that are used are also not open source. >> Um you mentioned there's a congestion issue if there's too many nodes. Is that correct? So, basically you couldn't use that for as alternative communications uh at concerts or something like that. >> It depends. Um, so the one thing I completely left out is these um, presets that you can do. Um, the default preset as I said maxes out at about 100 nodes, but you can there's one that has 20 times the bandwidth. So, you can scale it up quite a bit larger, especially if the area is uh smaller. So, many people have used it successfully at festivals. Especially there if you are in a group, you don't have to um, coordinate with anyone else. You can choose a fast preset and just message each other. Uh, yeah. But of course it's a shared medium and the routing protocol is quite simple on purpose. So, there will always be a congestion that you hit. >> And theoretically if everyone started using this technology then it would practically become unusable. Is that correct? Because then >> That's pretty pretty sure. >> everyone would congest each others. Okay. Thank you. >> Yeah. >> Okay. So, you you mentioned about commercial device being available to just buy and get started. And we already heard that apparently 800 MHz is better than 400. Is there anything else to to keep in mind when I would start looking for the first device to buy? >> Um so, for me I I bought this one that is called a seat wheel tracker. Um what I found appealing is that it has a display. So, you can even if you haven't haven't connected it to a phone, you can get at least interact it interact with it a bit. And that you can just carry it on you. So, maybe those I would call this category tracker. And they're announcing it as that. So, that might be a good first note. If you then have ideas, you can also go to the extreme where you just buy the dev kit and put it into something else that you're designing. Or so, you shouldn't should definitely not start buying a solar node and put it on your roof if you don't if you're not not already into it a bit. Yeah. >> All right. Thank you. >> Okay. Uh have you already tested Mesh Core, the other Laura system? >> Yes. So, I I left it out here. Of course, Mesh Tastic is not the only way to do uh Laura based communication. There's also Mesh Core. Um Mesh Core has a different focus, I would say. So, they're splitting um nodes that are just for repeating versus nodes for for end users. Um in that way you can reach extreme distances. Um so, they have a real routing protocol and have like I think 64 hops. So, in Graz I could talk to people in Slovakia. Um and uh the good thing is if you buy a commercial node like this, you can flash either firmware on it, so you actually don't have to decide. In the beginning I bought two and had one on Mesh Core and one on MeshTastic. Um, I think I just, uh, the the local community in Graz was easier to get into with MeshTastic. There was no technically reason to choose one over the other for me. Um, I know there's a lot of drama going on, but I'm just not participating in that. >> Anybody else?