Build a node
Prototype
MeshSat is a prototype in active development. Its dependability is unproven. Do not rely on it for life safety.
There are two versions. v0 is the bench unit the first tests ran on. v1 is the one meant to become a product. v1 has not been built yet: its wiring below comes from LILYGO's schematic, and this page will change once it has run on hardware.
v1: T-Beam Supreme
Parts
| Part | Notes |
|---|---|
| LILYGO T-Beam Supreme, 868 MHz | ESP32-S3, SX1262 LoRa, u-blox M10S GPS, AXP2101 power chip and a holder for one 18650 cell |
| RockBLOCK 9603 | with its 10-pin cable |
| One 18650 Li-ion cell | we use a Samsung INR18650-35E |
| Peli 1020 case | 135 x 90 x 43 mm inside. By the dimensions, the T-Beam (100 x 33 x 28 mm) and the RockBLOCK (45 x 45 x 16 mm) fit side by side; not dry-fitted yet. The Peli 1050 is the roomier fallback |
| IP68 panel-mount USB-C | charging and flashing through the case wall. It must carry the data lines, not only power |
| 12 mm momentary panel button | wired across the T-Beam's own power button |
| Waterproof SMA bulkhead cable and an 868 MHz antenna | the LoRa antenna sits outside the case |
| 90 degree USB-C adapter | about 21 mm is left at the T-Beam's USB-C end, too little for a straight plug |
Wiring
Four wires between the T-Beam's header PM1 and the RockBLOCK's connector:
| T-Beam PM1 | RockBLOCK |
|---|---|
| pin 13, U0TXD (GPIO43) | pin 6, TXD (the modem's input) |
| pin 12, U0RXD (GPIO44) | pin 1, RXD (the modem's output) |
| pin 9, DCDC5 | pin 8, power in |
| pin 8, GND | pin 10, GND |
- Leave RockBLOCK pins 7 (OnOff) and 9 (Li-Ion) unconnected. A floating OnOff means on.
- The panel button goes across the T-Beam's power button (SW3 on the schematic, PWR_KEY to GND). A short press turns the node on, a long press turns it off, and the RockBLOCK goes off with it.
- Screw the LoRa antenna on before the first power-up. The firmware transmits within seconds of booting, and LILYGO warns that transmitting without an antenna can damage the radio.
- The RockBLOCK's antenna side faces the lid, towards the sky.
Power
The RockBLOCK runs from the T-Beam's DCDC5 rail at 3.7 V. The firmware switches it on at boot and keeps it on while the node runs, so incoming messages are not delayed. The rail is a step-down from the cell, so once the cell falls below about 3.8 V the modem's supply follows it. The RockBLOCK needs 3.0 V or more.
The Meshtastic firmware the T-Beam ships with keeps DCDC5 off. With that firmware the RockBLOCK stays dark, which is expected. It powers up once the MeshSat firmware is on.
v0: XIAO ESP32-S3
| Part | Notes |
|---|---|
| Seeed Studio XIAO ESP32-S3 | the ESP32-S3 kit with the Wio-SX1262 on its B2B connector, 868 MHz |
| RockBLOCK 9603 | with its 10-pin cable |
| A 5 V source rated for at least 500 mA | for the RockBLOCK. A USB-C power bank works |
| XIAO ESP32-S3 | RockBLOCK |
|---|---|
| D6 (GPIO43) | pin 6, TXD (the modem's input) |
| D7 (GPIO44) | pin 1, RXD (the modem's output) |
| pin 8, power in: the 5 V source | |
| GND | pin 10, GND, shared with the 5 V source |
Use the XIAO's own pads
The Wio-SX1262 board also has pads labelled D5, D6 and D7, but on the ESP32-S3 kit they are not connected to anything. Wires on those pads leave the modem silent.
A power bank's USB-A port can switch itself off because the XIAO draws so little; use its USB-C port. Never feed 5 V into the XIAO's 5V pin while the XIAO is plugged into a computer: that pin is the USB supply line with no diode. Full wiring, power notes and a bench console for testing the modem link: BENCH.md.
Firmware
Build meshsat-firmware with PlatformIO Core 6.1.19. Version 6.2.0 stops with ModuleNotFoundError: SCons.Tool.FortranCommon.
pip install "platformio==6.1.19"
git clone https://github.com/meshsat/meshsat-firmware.git
cd meshsat-firmware
pio run -e meshsat-tbeam-s3-rockblock # v1; use meshsat-xiao-s3-rockblock for v0Flash it over USB with esptool. Erase first on a board that ran something else:
esptool --chip esp32s3 --port /dev/ttyACM0 erase-flash
esptool --chip esp32s3 --port /dev/ttyACM0 write-flash \
0x0 .pio/build/meshsat-tbeam-s3-rockblock/firmware-meshsat-tbeam-s3-rockblock-*.factory.bin \
0x670000 .pio/build/meshsat-tbeam-s3-rockblock/littlefs-meshsat-tbeam-s3-rockblock-*.binThen set it up like any Meshtastic node, with the Meshtastic app or CLI: your region, an owner name, and Bluetooth pairing set to a fixed PIN of your own. Updates go over USB the same way; over-the-air updates are not supported.
Pair with MeshSat Android
In MeshSat Android 2.9.10 or later, open Settings, tap Scan for Meshtastic devices, and tap Connect next to your node. The scan lists every Meshtastic device in range, so pick the node by its name: v0 advertises as MSIR_ followed by four hex digits. Pair with your fixed PIN when the phone asks.
With Use the node's modem on (the default), the app takes the modem while it is connected. After a restart it reconnects to the same node and takes the modem back by itself. Disconnect in Settings stops that until you connect again. On v1 the modem answers about 10 seconds after power-up, and the app keeps asking until it does.