Satellites
Sats, short for satellites, are small devices that sit beside a boardShort for bulletin board, a BBS. On this site, one BBS and the community that meets on it. and add to it over the air: a camera in the garden, a switch in the shed, a game on the shelf. No cable between them, and nothing goes through your router.
The family
Two kinds do the work. An orbiter feeds your board: pictures, switches, sensors, your Home Assistant. A door sat is one a caller goes into, to a game or a program of its own. A repeater carries the link out past where a board can hear, and anybody can build their own.
How it works
Your board is the hub and every sat is on a spoke: paired once, then straight from chip to chip whenever there is something to do.
Pair once
LINK PAIRon the board, power on the sat, and the two agree a key only they hold. A four-digit code on each end proves nobody got in the middle.The board asks
A caller types
SNAPSHOT, a timelapse comes round, or a motion sensor sees something. The sat wakes and does the job.It comes home sealed
Over ESP-NOW, chip to chip, every frame sealed with the pair's key. A frame that does not open is dropped, whoever sent it.
The board files it
A picture goes in Photos, exactly like a snap from a camera built into the board.
Pick a sat
How a sat talks to its board
Every sat speaks the µnleashed link: one small protocol over ESP-NOW, the radio built into every ESP32, straight from one chip to the other. The board stays on your Wi-Fi as it always does, and the sat finds it on the same channel by itself, even when the router moves.
- Paired by hand, not from the air. The sysopThe system operator: the host who runs a board, sets its rules and looks after it. types
LINK PAIR, presses something on the sat or starts it up, and says yes to the four-digit code the board shows. Having your hands on both is what makes the sat yours. - Sealed on every frame: encrypted and checked, with the key only the pair holds.
- Up to eight sats on one board, and any board can have them, the ESP32 dev board (about $15) included.
On the wired Ethernet board, set up Wi-Fi as well. Sats talk over the Wi-Fi radio. From firmware 1.2.1 that board joins Wi-Fi beside the cable, so sats pair as on any other board and callers still come in over the wire; with no network set, the board says in SATS that they cannot pair.
Camera sats
A cheap ESP32-CAM, about the size of a stamp, adds a camera to any board with an SD card, anywhere in radio range: at a window, in the garden, over the workbench. It takes pictures on request, on a timer or when it sees movement, and the board files them in Photos like a snap from a built-in camera. One camera sat can be shared by up to five boards.
The board's side is in firmware 1.2.0: SATS and CONFIG sats are on every board, and SNAPSHOT n picks which camera answers. The sat's own firmware, camsat 1.1.0, came out the same day and installs from its page, straight from your browser. Together, a board with a screen and a camera sat is the setup we recommend.
Build a camera satHow the camera works for callers
Coming next
Remote control, Home Assistant, repeater and custom sats are not built yet and have no version. Door sats arrived in firmware 1.2.0 on the board's side: UPLINK is there, ready for the first door sat to go into. The up-to-date list is on the roadmap.
Remote control
An orbiter with switches, relays and sensors on its pins: GPIO on another board, somewhere your board's wires do not reach.
Home Assistant
An orbiter that bridges Home Assistant to your board.
Repeater
A box that passes the link on, so a board reaches a sat sitting further off than it can hear by itself, and works with others to reach further again. Nothing about range is said here, because nobody has measured any, and none of it is built. The design, the drawings and what it would cost you in airtime are on the repeater page.
Custom
The link is an open protocol, so a sat of your own is a program on a cheap ESP32 that speaks it.
Door sats
A doorA game or program that a board hands you over to, and brings you back from when you finish. is a game or a program a board hands a caller over to, and brings them back from when they finish. A caller goes into a door sat with UPLINK, from firmware 1.2.0. A door sat runs doors: the board tells it who the caller is, how wide their screen is and how long they have left, and takes them back when the door is done or the time is up. Several callers can be in one at once, each in their own session.
A door sat can sit on the link, or on a serial cable where there is no radio, so a PC or a Raspberry Pi with a USB serial adapter can be one too. The board never takes anything a door sends as a command: the door plays on the caller's screen and nowhere else.
Building your own
The link is published with the firmware, in LINK.md, and a sat's software lives in a repository of its own, so anybody can write one. A door author gets one line of plain text that says who the caller is, and can read it in a few lines of any language.