I built a mini tower for an Orange Pi Zero to serve Home Assistant. The case is 3D printed and the sides are acrylics cut on CNC.
The Orange Pi Zero has one USB port on board and two more USB connections on the header pins. I used one of them for a USB to SATA adapter and connect an SSD to boot from it instead of the microSD card. (boot OPi Zero from SSD)
I 3D printed a USB socket cover to connect the second USB from the header pins and use it for a Bluetooth dongle. The extra USB port might be used in the future for a zigbee adapter.
I use a USB Type-C socket as a power input to power a 5V module that charges a 18650 battery and acts as a UPS in case of power failure. An illuminated switch on the front is connected with header pins to distribute power on all of the components that require 5V. I use the same method for ground.
The OLED on the front shows info about the device (cpu usage, temp e.t.c). It’s connected with I²C. The three buttons allow me to navigate in a menu for more info or execute commands like restarting Home Assistant, Reboot, Shutdown and more.
Another module (ADS1x15) reads voltage from the battery and the USB input. It sends them to Home Assistant with MQTT (using mqtt io). A logic level converter connects the ADS1x15 I²C with the Orange Pi Zero which is 3.3V tolerant.
The cooling fan is connected with a simple circuit (NPN transistor, two resistors and a diode) to control it using MQTT. I can use the menu or Home Assistant to send MQTT messages and enable/disable the fan.
The cooling fan is connected with a simple circuit (NPN transistor, two resistors and a diode) to control it using MQTT. I can use the menu or Home Assistant to send MQTT messages and enable/disable the fan.