Initial import

.gitignore

@@ -6,9 +6,11 @@
 *.bak
 *.bck
 *.kicad_pcb-bak
+*.kicad_sch-bak
 *.sch-bak
 *~
 _autosave-*
+\#auto_saved_files\#
 *.tmp
 *-save.pro
 *-save.kicad_pcb
@@ -24,3 +26,8 @@ fp-info-cache
 # Exported BOM files
 *.xml
 *.csv
+
+rpi-cm-ssd-backups/
+# Do not upload 3D files (potential licensing issues)
+lib/**/*.[Ss][Tt][Ee][Pp]
+lib/**/*.[Ss][Tt][Pp]

README.md

@@ -0,0 +1,48 @@
+Lean Raspberry Pi CM4 base for Homeassistant
+===
+
+This is a base board for Raspberry Pi Compute Module 4 targeted for use as [Homeassistant](http://homeassistant.io/) server.
+
+## Features
+
+* a M.2 M-key port for NVMe (form factors 2230 and 2242 drills are available)
+* an included energy meter to measure the server's power consumption
+* two temperature sensors (both front and back to cover CM4 and NVMe)
+* USB PD support
+* ZigBee/Thread/Matter support via Silicon Labs MGM210P "Mighty Gecko" wireless module (same as used in Homeassistant Yellow)
+* external antenna support for wireless module to increase transmission performance
+
+## Requirements
+
+* 12V USB PD compatible power supply (USB-C connector)
+* 2230 or 2242 M-key NVMe module (or a CM4 with internal eMMC memory)
+* (optional) equipment to flash the USB PD controller firmware residing in internal EEPROM (for instance USB-I2C adapter)
+
+## Description
+
+This module only exposes very few interfaces of the compute module to save on board space and keep BOM small.
+If a more complete access to the device with more features included is required,
+[Homeassistant Yellow](https://www.crowdsupply.com/nabu-casa/home-assistant-yellow) might be worth a look.
+
+This base only features two USB 2.0 ports (for easy extension of other hardware like a Bluetooth dongle, external memory, etc.),
+a M.2 NVMe interface to get a fast storage to run Homeassistant's database on and some monitoring devices.
+
+Since many users want to have an overview over devices' power consumption in their setup, a energy meter is
+observing the power consumed by the CM4 and the additional M.2 card. Together with two temperature sensors
+and the Pi's internal sensors, the device's health state can be neatly captured and visualized in Homeassistant.
+
+The sensors are all using a I2C protocol which is translated to the CM4 `SPI0` using a NXP
+[SC18IS604](https://www.nxp.com/products/peripherals-and-logic/signal-chain/bridges/spi-to-ic-bus-bridge:SC18IS604)
+bridge. That way only one internal bus is used and others are free for possible future extensions.
+
+## Pictures
+![Front view](images/front.png)
+
+![Back view](images/back.png)
+
+## PCB manufacture link
+
+The project has been prototyped at [AISLER](https://aisler.net/p/MXNUZCCB).
+
+## License
+GNU GPL v3 or newer