Getting Started
Building the Project
You will need:
- Python >= 3.8
- KiBot (see installation instructions)
Clone this project and run ./build.sh. You will get a selection of the possible modules to be built. Tests will be executed and the build result is placed in the out folder.
Run mkdocs serve to see this documentation.
Project structure
| Folder | Purpose |
|---|---|
| ./casing | Construction files for the casing |
| ./configs | KiCad-Export configuration |
| ./development-board | Design for the development board |
| ./docs | Documentation |
| ./ethernet-extension | Design for the Ethernet module |
| ./libraries | Electric symbols, footprints and 3D models |
| ./metering-module | Design for the metering module |
| ./nbiot-extension | Design for the NB IoT module |
| ./out | Build output folder |
| ./panel-module | Design for the panel module |
| ./soc-module | Design for the SoC module |
Conventions
Markings
- Each PCB has an etched label for "TOP" and "BOT" marks
- Each PCB has an etched label for the product serial following the pattern: SR-XX-NNN (e.g. SR-SM-021)
- The product serial start with "SR" for "Satellite Rail", the next two characters are reserved for the module, the 3 digits represents the version
| Serial | Module / Part | Current Version |
|---|---|---|
| SR-SC-XXX | SoC Module | v2.0 |
| SR-EM-XXX | Electric Metering | v2.0 |
| SR-CM-XXX | Current Loop Metering | v2.0 |
| SR-MM-XXX | MBus / WMBus Metering | v2.0 |
| SR-ET-XXX | Ethernet Module | v2.0 |
| SR-NB-XXX | NB IoT Module | v2.0 |
| SR-LR-XXX | LoRa / LoRa WAN Module | v2.0 |
| SR-PN-XXX | Panel Module | v2.0 |
Tracks / Vias / Grids
Despite of the low energy consumption of the MCU itself, we are planning with a maximum current of 1A to be future proof for extra extensions that have a higher energy demand (LoRa, NB IoT, ...).
We chose two different of track widths for main power and for data lines (0.25mm / 0.5 mm) and planned a minimum temperature of 0°C. See the table below.
| Track (mm) | Track (mil) | 10° | 20° | 30° | 40° | 50° | 60° |
|---|---|---|---|---|---|---|---|
| 0.1mm | 4mil | 0.4A | 0.6A | 0.8A | 0.9A | 1.0A | 1.1A |
| 0.2mm | 8mil | 0.7A | 1.0A | 1.2A | 1.4A | 1.6A | 1.7A |
| 0.3mm | 12mil | 0.9A | 1.3A | 1.6A | 1.8A | 2.0A | 2.2A |
| 0.4mm | 16mil | 1.1A | 1.5A | 1.9A | 2.2A | 2.4A | 2.7A |
| 0.5mm | 20mil | 1.3A | 1.8A | 2.2A | 2.5A | 2.8A | 3.1A |
| 0.6mm | 24mil | 1.4A | 2.0A | 2.4A | 2.8A | 3.1A | 3.4A |
We chose a 0.1mm grid for all PCB designs, because our casings and mechanics are also measured in millimeters.
We chose 0.8mm 0.4mm vias.
Pin Out
| Pin ESP | Pin Satellite | Pin Name | Standard Purpose |
|---|---|---|---|
| 1 | East 1 | GND | Ground |
| 2 | West 1 | 3V3 | Power supply |
| 3 | West 2 | EN3 | Reset |
| 4 | West 3 | I36 | I2C Interrupt |
| 5 | West 4 | I39 | UART 1 RX |
| 6 | West 5 | I34 | SPI 2 MISO |
| 7 | West 6 | I35 | UART 2 RX |
| 8 | West 7 | IO32 | SPI 2 MOSI |
| 9 | West 8 | IO33 | SPI 2 CLK |
| 10 | West 9 | IO25 | UART 1 TXE |
| 11 | West 10 | IO26 | UART 1 TX |
| 12 | West 11 | IO27 | SPI 2 CS (Ethernet) |
| 13 | West 12 | IO14 | Ethernet Reset |
| 14 | West 13 | IO12 | |
| 15 | NC | GND | Ground |
| 16 | West 14 | IO13 | Status LED |
| 17 | NC | NC | Internal Flash / RAM |
| 18 | NC | NC | Internal Flash / RAM |
| 19 | NC | NC | Internal Flash / RAM |
| 20 | NC | NC | Internal Flash / RAM |
| 21 | NC | NC | Internal Flash / RAM |
| 22 | NC | NC | Internal Flash / RAM |
| 23 | East 13 | IO15 | UART 2 TX |
| 24 | East 12 | IO2 | UART 2 TXE |
| 25 | East 11 | IO0 | Setup Button |
| 26 | East 10 | IO4 | Ethernet Interrupt |
| 27 | NC | NC | Internal Flash / RAM |
| 28 | NC | NC | Internal Flash / RAM |
| 29 | East 9 | IO5 | SPI 1 CS (SD) |
| 30 | East 8 | IO18 | SPI 1 CLK |
| 31 | East 7 | IO19 | SPI 1 MISO |
| 32 | NC | NC | Internal Flash / RAM |
| 33 | East 6 | IO21 | I2C SDA |
| 34 | East 5 | URXD0 | UART 0 RX |
| 35 | East 4 | UTXD0 | UART 0 TX |
| 36 | East 3 | IO22 | I2C SCL |
| 37 | East 2 | IO23 | SPI 1 MOSI |
| 38 | East 1 | GND | Ground |
| NC | East 14 | Shield | Shield / PE |