HOW IT IS TODAY
You are given
An alert arrives on your phone: from an operator, over infrastructure that belongs to somebody else. When that infrastructure is down, you receive nothing. And you can send nothing.
Beside it, at the same scale: a 5 zł coin and an AA battery. The body is 56 × 24 mm, exactly as wide as that coin.
a link when nothing else is working
It starts with two people
Two flats on opposite sides of a city. Two houses at either end of a village. A block of flats and a plot of land. You and someone you care about. A small radio cube pairs with your phone and carries messages onward, from one neighbour to the next, with no internet, no mobile coverage and no subscription.
This network is alive: more than 2,200 devices like Biper were heard in Poland within the last month. See the map
The smallest thing that really works is two cubes. Every pair after that extends the range for everyone, because the Biper network has no headquarters and no operator. It is as large as the number of people who joined it.
heard: 3pace: 24 (lower = faster)
Why any of this
The connectivity you are given, and the connectivity you have
September 2024, the Kłodzko valley in south-western Poland. The flood cut the power, and the signal went with it: the operators reported at the time that nearly half of the local base stations were down. For the first days the town of Stronie Śląskie was cut off: no roads, no power, and no way for anyone there to tell their family they were alive.
HOW BIPER WORKS
You have
The cube belongs to you and works on its own: no operator, no mast, nobody’s permission. Two cubes already make a link between two homes, and a neighbour with a third extends the range of both.
three short films
Watch before you read
Everything in these films is the real interface (system 0.9.0): the site, the screen emulator held to pixel parity by a gate, and the panel from the cube’s flash in its trial mode, radio off. No mock-ups.
Network philosophy
Range does not come in the box. Your neighbour adds it.
You buy a cube for yourself. Your neighbour buys one for themselves. From that day the two of you have a link that neither of you had before.
A dozen cubes in one district or one village make a neighbourhood that hears itself: someone is at home, someone is on the road, someone is at the far end of the street. Messages between areas are carried by repeaters, cubes placed permanently in a good spot by someone who looks after them. That is why we talk about rooftops and about the site owner’s permission as often as about the cubes.
The Biper network has no headquarters and no operator. It is as large as the number of people who have joined it.
And you are not starting from zero: a Biper cube transmits on the open MeshCore network and talks to every device on it, not only to another Biper cube. When we checked on 19 August 2026, the official map showed more than 4,400 reported nodes in Poland; over 2,200 of them on air within the last month; and counts over 57 thousand worldwide.
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Two cubes
A link between two houses
Two phones, two cubes and no operator in between. Enough for the first conversation.
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A dozen
A neighbourhood that hears itself
Nobody on your list? Send an Advert — that is what MeshCore calls a short "I am here" over the air, a short “I am here” over the air. The more cubes around you, the more often someone answers.
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A good spot
A repeater on a roof
Repeaters are what carries messages between areas. What a good site needs, we set out below. Four conditions
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Before it matters
The family ceremony
Five minutes at the table, while nothing depends on it yet. The step-by-step guide
Range
A cube on the table reaches the yard. A mast reaches the next town.
How far you are heard comes down to height and by what stands in the way. Transmit power in Europe is capped by regulation and identical for everyone, and a pricier board does not send any further.
These four examples come from the people who run the Polish MeshCore network. This is not our measurement. We have no figures of our own yet and will not give any until we go out into the field. Expect roughly this much. Do not build an emergency plan on it.
- a few hundred metresa cube on the ground floor, in a citywalls and floor slabs take the most
- a few kilometresthe same cube outdoors or higher upa window, a balcony, open ground
- 5–10 kma repeater on a roofa fixed site, mains power, antenna above the ridge
- 30–40 kma repeater at a high pointa hill, a tower, a mast — the backbone
295 kilometres and ten hops
Between Czaplinek and Łódź there are 295 km in a straight line — and a message has a way through. Not because the cubes are powerful, but because along the way people put repeaters up high and keep them running: Wałcz, Piła, Przybychowo, Krzyszkowo, Puszczykowo, Krzykosy, the “Biały Tower” node, Turek, Zygry, Łódź.
You add the last kilometre. The thirty kilometres between towns are added by a mast — and that is exactly why roofs get as much attention here as the cubes themselves.
For the curious: the geometry of this route
The chain only closes with hops of up to 40 km; cap the longest hop at 35 km and it does not close at all. This is geometry, not a radio measurement: node positions from the public map plus the terrain profile, without the heights of other people’s antennas, tree canopies and buildings. The first hop out of Czaplinek is 35.4 km — bare line of sight needs an antenna 40–44 m above the ground there, and a clear corridor for the wave (60% of the first Fresnel zone) takes 95–114 m. That is a job for one good spot in the area, not for your window.
Network map
There is one network, and the maps are not ours
We do not draw a map of our own. The real nodes live on community maps. That is where you check whether anyone is already transmitting near you, and which way a message would travel.
The whole network, live
Official MeshCore map
map.meshcore.io
Every country, every node type. The place to start when you want to see how large this network is.
Poland, with routes
MeshCore Polska map
mapa.meshcorepolska.org
The same network seen from the Polish side. It can draw a route through named repeaters, compute the terrain profile between two points and show whether they see each other.
Coverage measured, not modelled
MeshMapper — West Pomerania
szz.meshmapper.net
A map of what is actually heard: collected from drive-testing and from listening stations run by local operators. Green means a fresh contact, red means nothing has been heard from there in a long time.
Each one is run by different people, and they show only the nodes somebody reported. A missing point does not mean nobody is there; a point that is there does not mean the node is up right now or that it will reach your antenna.
How to start
Three steps lead to the first message.
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Step 1
Buy a cube
The Unit C6L, the same cube we are testing here. Two of them ideally, because a conversation needs two sides — in Poland a pair like that is roughly 220 zł.
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Step 2
Install the system from this page
You connect the cube to a computer with a cable and click. The page writes exactly the one file we have checked.
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Step 3
Pair the phone and write
The installer writes our system. You talk in the Biper panel: hold the button for three seconds, the cube sets up its own Wi-Fi, and the panel opens in your phone's browser. If you prefer the official MeshCore app, you can flash stock MeshCore onto the cube — it is not locked, and our installer will always bring the Biper system back.
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Later
Help the network reach further
Once you are talking, you can put up a repeater in a good spot.
From the box to a conversation
What you hold, and what you do with it
Four things in the box, two minutes to put them together and one path that a message travels. The phone comes later and reaches the cube over Wi-Fi the cube sets up itself.
01
Two antennas
The longer one is the long-range radio, the shorter one handles the cube's Wi-Fi. Screw both into the gold sockets before you connect power.
02
The Biper cube
Inside there is an ESP32-C6 and an SX1262 radio. On top, a small screen and one button.
03
USB-A → USB-C cable
First install: a computer. Later: a suitable power bank.
02–03 / WHAT GOES WHERE
The antenna goes on before the cable.
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1
Screw on both antennas
By hand, no tools. Do not run the transmitter without antennas.
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2
Connect the cable to a computer
You open the installer on this page and click. A few minutes, with nothing to download.
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3
Day to day: a power bank
Once the system is in, the cube takes its own power and the phone stays separate, in your hand.
FIRST RUN
computer → USB-C → cube
LATER IN THE FIELD
power bank → USB-C → cube
The C6L arrives in a factory enclosure. That leaves the antennas to screw on and the cable to plug in.
1 · SMA 868 MHz
2 · USB-C, right edge
Phone A
short hopthe cube's Wi-Fi
Cube A
LoRa / mesh
868
Cube B
the cube's Wi-Fi
Phone B
Installation
Install the system straight from this page.
No programs to download: the browser reaches the cube over a USB cable and writes exactly the one file we have checked. It writes our system: the one with the screen, the LED and the panel served from the cube’s memory. Underneath runs open MeshCore, the same network everyone joins. You need a computer. Chrome or Edge is easiest; Opera and Firefox from version 151 work too.
One cube: factory enclosure, a screen and antenna sockets
M5Stack Unit C6L
Paid partnership · Botland is a project partner. You can buy the device anywhere; the system works the same.
Technical details
- System file
- Biper system v0.9.0 (on MeshCore v1.17.1)
- SHA-256
- c46a2871bc4e…
- Product code (SKU)
- M5Stack U202
We are walking the same path right now on four more units
If something goes wrong, the same file can be written again; the installer page shows you how to start over.
The phone is for talking. The system file goes in from a computer; do not try it from a phone.
tap a state to see it on the screen
The screen, the LED, the buzzer and the panel are our system — and it is what the installer on this site writes.
the language of the screen
Six things the cube can say
The animation is the host, the state is a guest. When nothing is happening, the field drifts and carries the word BIPER. When something happens over the air, the state takes the screen for a moment and hands it straight back.
one button
Four gestures and the learning is over
There is one button to work with: the whole pad under the screen, on the front. You press it with your thumb, holding the cube in your hand. A second one sits on the side, for service: a short press resets it, holding it puts the cube into flashing mode; in normal use you never touch it. No menu, no confirmations, no advanced mode. Everything the device does without a phone fits into four gestures. The fifth one, the one that wipes it, is in the box below.
- clicknext screen: wave → SIEC → rings → info
- two clicksninja mode: silence, the LED goes out, the screen dims
- 3 secondshotspot: the cube sets up its own Wi-Fi, the password stands on the screen
- three clicksradio switch: SIEC or SAM — the whole thing is described below
voice and light
The buzzer and the LED speak when you are not looking
The cube has two lights and they are easy to mix up. The green one on the bottom edge, by the Grove socket is the factory one. It burns steadily and means exactly one thing: the power is on. The second sits in the slit in the button, under the screen. That one is ours to drive, and that one tells you what is happening. Then the buzzer: two or three notes per event, never a tune.
The six colours below are that second LED, the one in the button — this is how it lights on our system.
- white flashthe cube has just woken up
- blue flasha phone has connected
- magentaa message is waiting
- blue, pulsing slowlythe hotspot is on
- green pulse every three secondsnothing is happening, the network is alive
- darkninja mode
Press any button below: you will hear the same pitches and lengths the cube sends to its buzzer, and and on the cube beside it you will see the same flash it sends to the LED.
The pitch and the rhythm are exact. The timbre is not, because the buzzer in the cube sounds harsher than a phone speaker and the page does not pretend otherwise. The rhythm of the light is real too, but we draw the flash itself with a short fade: on our system the pulse lasts 90 ms and you catch it out of the corner of your eye in a dark room, while on a display it would vanish between frames. In ninja mode there is no sound and no light, but the radio keeps transmitting. Ninja silences the cube for the people next to you, not for a receiver: anyone with listening gear hears it like any other cube. That is how it should be out in the field, when you do not want to be heard or seen in a room.
three clicks
Who your cube works for
The cube hears more than what is addressed to you. It also hears messages from neighbours who are too far from each other, and it can pass them on. The whole network stands on that: the range between two houses is made by the cubes standing in between.
Three clicks decide whether yours does. SIEC passes other people’s messages on, SAM sends only yours. Neither mode is a cut-down one; straight out of the box SIEC is on, because a network of cubes that do not relay reaches exactly one hop. SAM makes sense where you count every hour out of a power bank.
Every Biper cube relays packets from the moment it powers on — which differs from the system we build on, where you switch that on yourself. We chose it that way because a network in which nobody relays ends at one hop. It has a price: the 868 MHz band is shared and carries a transmit-time limit, so the cube does not transmit whenever it likes, only as much as the rules allow — the more cubes talk at once, the longer each waits its turn. Its power cannot be turned up, and do not try: the limit covers radiated power including the antenna, and it is the operator who answers for it.
SAM is not a silence mode. It stops relaying other people’s packets, but the cube still transmits yours: your messages, delivery receipts, and every so often a short “I am here” that lets neighbours add you to their list. A radio that transmits can be located — anyone who truly does not want to be heard has to switch the cube off, not switch its mode.
The cube shows which mode is on, on its SIEC screen, one click from the main one — not just for a moment after you switch. And the cube stays in that mode after the power goes, because it has no battery and a “restart” happens to it on its own: a cable knocked out, a power bank taken away. A switch that quietly goes back to the other mode after that would be worse than no switch at all.
Both images are screenshots straight from the code that draws this screen inside the cube, not artist’s impressions. For the few minutes the hotspot is on, that same screen gives all its space to the Wi-Fi password, and the mode moves to the panel on your phone — on its first screen, in the “your cube” card, next to the uptime and how much of the window is left. This is the system the installer on this site writes.
Important
Ten seconds wipe the cube
Holding the button for ten seconds wipes the cube back to factory state: its identity, the contact list and the channel key are gone. There is no undo — after the wipe the cube is new, and everyone you talked to has to meet it again.
There is no “are you sure” box. Instead, from the fourth second the screen counts down and writes PUSC ABY ANULOWAC. You let the button go and nothing happens. Six seconds of warning is the only protection that fits on a screen the size of a postage stamp with one button to work it.
What it is for: whoever takes your cube can read the messages off it and write in your name. Ten seconds takes all of that away from them. This is not theft protection — it is the last thing you can do when you see the cube is about to leave your hands.
This gesture, like the screen, the LED and the panel, belongs to our system. It is the system the installer on this site writes.
the phone as a keyboard
A panel you will not find in any app store
The cube serves the panel from its own memory over Wi-Fi that it sets up itself. No account, no app store, no internet. The phone is the screen and the keyboard here. None of this leaves the two devices on the table. These are screenshots of a working panel, not plans. It ships with our system file — the one the installer on this site writes.
power
The cube has no battery
The board simply came out that way. The Unit C6L takes its power from USB-C and has neither a cell nor any way to measure one. We say it plainly, because a device for emergency communication that goes quiet when the cable comes out has to say so on the page, not in a leaflet at the bottom of the box.
The consequence is simple and, as it happens, convenient. The cube lives as long as the power bank you gave it. The same one you charge your phone with. There is no cell of its own to watch over and nothing here ages in a drawer.
We do not know how many hours any given power bank buys you. That needs a USB meter and a full day of running in each mode. Until then no figure will appear here or in our materials.
where things are
Cable on the side, button on the front
The USB-C socket sits on the right edge, looking at the cube from the screen side. On the left edge the manufacturer put the LED and the RESET/BOOT service button. On the back they labelled both: “POWER-IN / PROGRAM” by the socket and “PRESS:RESET, HOLD:BOOT” by the button. The system goes in through that same socket, so the power bank cable is the install cable too.
Community infrastructure
Join, then help the network reach further.
Height, a clear view, steady power and a responsible maintainer matter more than the transmit power on a datasheet.
Phone + cube
Personal cube
Talking and discovering the network.A fixed site
Community repeater
Passes packets between areas.Off-grid ground
Solar node
Autonomous power and a service plan.A good site has four things
- the site owner’s permission
- height and a horizon as clear as possible
- safe power and an enclosure
- a maintainer, a written record and a service plan
Planning a repeater or a solar node?
We analyse repeater hardware, ready-made solar kits included, on the project page, with the evidence and the open questions.
The analyses are on the project pageAn honest state of the work
Test status, point by point
SITE AND MAP
WORKS
Checked in Polish and English, including the error states.
WEB INSTALLER
CHECKED
The owner walked the whole path as a customer: install from this page, pairing, the radio preset and a conversation between cubes.
FIRST MESSAGE
WORKS
On 17 August a message crossed between two cubes installed entirely through this page — at that time still on the base MeshCore file. On 20 August the same pair was already talking on our own system in both directions, with a delivery confirmation in 1.2 seconds.
What happens next with the four new cubes
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Inspection
So far two of the owner’s cubes have walked the path. The four new ones start with an inventory and an inspection, with nothing plugged in — because repeatability is proved on units you do not know.
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Installation through this page
Each of the four gets the system the way every customer will: with the installer on this page, no shortcuts and nothing beyond the cable that comes in the box.
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Conversation and decision
The pairs talk to each other, and only then do we know whether the path works away from the author’s desk. We describe the results and the support decision on the project page.
Common questions
Does this work without the internet?
Yes. Messages travel by radio, from cube to cube. The internet is needed neither for a conversation nor for the network to run.
Do I have to know how to program?
No. You write the system from a computer, with one click on this page, and you talk on your phone, in the panel the cube serves over its own Wi-Fi. Neither step asks you to program anything.
Which cube should I choose?
One: the M5Stack Unit C6L. It has a factory enclosure, a small screen and two antenna sockets. We are looking for alternatives with those same three traits, so as not to depend on one manufacturer. We run the live comparison on the project page.
How much does it cost?
In Poland the cube costs 109 zł from our partner (price as of 19 August 2026); elsewhere check the M5Stack store. You need two to start, plus a power bank and a USB-C cable most homes already have. The system is free and the network has no subscription. The full shopping list with links is on the Kit page.
How far does one cube reach?
We have not measured that yet, and until we do we will not give a figure of our own. People from the Polish MeshCore network give the order of magnitude: a few hundred metres on the ground floor in a city, a few kilometres outdoors, 5–10 km for a repeater on a roof and 30–40 km for a repeater at a high point. The result depends on height and on what stands in the way. We set it out above, in the section on range, together with the arithmetic for one route across half of Poland.
Does the Biper map show real nodes?
Biper runs no map of its own and draws no invented points. We give you three community maps: the official MeshCore one, the Polish one (it draws routes through repeaters and the terrain profile) and MeshMapper, which shows measured coverage — from drives and listening stations. All three are run by other people and show only the nodes somebody reported.
Does the cube connect to the phone over Wi-Fi?
Yes. Hold the button for three seconds: the cube sets up its own Wi-Fi, shows the password on its screen, and the panel from its memory opens in your browser. Since release 0.9.0 the system in the cube carries no Bluetooth: the panel from its memory is the whole interface, and the cube's screen sees every conversation. Mind both antennas: the one the manufacturer describes as Wi-Fi carries the cube's own network (2.4 GHz), so both have to be screwed on.
Can a phone power the cube?
Some Android phones can power accessories over USB-C, but it depends on the model and on its power saving. The basic Biper route is a USB-C power bank.
Stay in the loop
I will tell you when something changes
The network grows, the system gets releases, and tests keep closing gates. Leave an address and I will write when something matters. No spam: this is the same newsletter that runs all of ESP32AI.ME.
Project model
What is free, and stays free
You pay for the cube in the shop you buy it from. There is no till to pass through on our side.
Everything that serves emergency communication is free and will stay free: the installer, the system file, the instructions and the guides. No safety feature here will ever start costing money. That commitment — and five more — is written down in the Biper Charter.
Supporting the project
A voluntary way to support the work is coming soon. It unlocks nothing: the site, the system and the guides work the same with it and without it.
A shop with ready-made cubes
There is none yet and we are not giving a date. We will come back to that question when the community grows enough for it to make sense.
Biper is a community project by Tomasz Fiedoruk
We are building the shortest repeatable path into the MeshCore network: Polish and English first, then more languages and regions — each with its own radio settings and its own testing.