Ceci est une ancienne révision du document !
I came across Meshtastic purely through a suggestion from YouTube’s algorithms since I’d previously looked up radio stuff in the past. The idea behind Meshstastic is to send text messages from device to device through radio waves, but rather than just going point-to-point, you can route through other nodes (aka: devices) to reach your destination. This means you can reach devices much further away than your device's antenna is capable of. You can go from point A to point B via F and Q, if need be.
Most of the devices require a mobile phone with the Meshtastic app, but you need only Bluetooth enabled to send the message from the phone to the device. The message is then sent from the device. You can have no SIM card and wifi off on the phone, and it’ll still work. Remember: the message is going via radio. The phone is not sending the message. There is at least one device (the T-deck) that has a built-in keyboard and is completely standalone.
Meshtastic is, of course, free and open source: https://meshtastic.org/
Devices
There are many devices that can run Meshtastic. The most well known is the Heltec V3. This can be bought pretty cheaply (~£20, sometimes £30 for two) from many Chinese suppliers with some supplying a small primitive antenna and case, but you could 3D print your own case. The files are out there for free. Just bear in mind that you need to supply power either through the USB-C socket on the device, or plug in a suitable battery.
NOTE: these devices come in 433 and 868 flavors. Most users in Europe and the UK are using 868, and the 433 is for the US. But, in theory, you can use anyone anywhere, but a 433 can’t connect to a 868. Just be wary of which version you’re buying.
Flashing
In the case of the Heltec, it comes with some basic software installed, but this needs to be replaced by Meshtastic. This is pretty simple since the Meshtastic site does most of the hard work for you. Using a modern browser you go to https://flasher.meshtastic.org/ and go through the three steps. Make sure you’re using a good quality, data compatible, USB cable. Not all USB cables can do data. Some are just for charging. Now you need to install the app on your phone.
With the app running, you link it to the device using Bluetooth. Hopefully, you’ll now see other people nearby. Now, this is the potential downside of Meshtastic: you might have no one else in your area who uses it.
There are a couple of online maps where people display their approximate location to allow others to see if there’s anyone around (https://meshmap.net/). You don’t have to appear on the maps.
I bought two devices and would leave one running at home while taking one with me to work and keep messaging my home unit to see what kind of distance I could get. Initially I was getting, at most, about 1km. Which is actually pretty good considering the placement of my home unit and the area I was testing in.
It’s definitely better to get your device as high as you can get it, and leave it running 24/7 as it’ll discover more devices in the area. My first setup was a tupperware container with the Heltec hooked to a USB battery pack. And it worked very well all things considered.
Antennas
If you want to reach further afield then you’ll need to use a good external antenna. I bought an 868 compatible yagi from Amazon and mounted it on my roof with V2 of my tupperware box now containing the connection to an external antenna and a larger USB battery pack that lasts for a good 5 or 6 days. For my other Heltec (that I take with me) and my T-deck, I bought a case that came with a battery pack and antenna from eBay.
Testing
With the new external antenna in place I started testing. I mounted the Heltec in its new case to the handlebars of my bike and peddled around sending messages to myself.
To my amazement I could easily message my home device from about a mile and a half away! And this is in the middle of the city. Only on one road which was heavily lined with trees did I get any issues in sending a message.
Conclusion
I’m still testing my devices. I’m hoping to go further afield during the nice weather and test the range to find my absolute limit. But even that changes as more and more nodes appear to extend the range. Remember, the more nodes online, the bigger the mesh gets and the more range everyone in that area gets.
So what’s the point of this? Well, imagine if you’re in a city where you experience power outages or natural disasters? Your power is out, maybe the cell towers are down (or overloaded), and you’ve no internet. How do you message people? Meshtastic. Gift some to your friends or relatives. As long as your area has enough people running a device(s), then, if nothing else, you might be able to even message a stranger to ask for assistance.
Of course, I’m not saying you should rely on these things. As if it all goes south the people running some devices might be a bit too busy to help route your messages or reply, but they’re definitely better than relying on the cell towers and internet if it all went pear-shaped.