A Raspberry Pi HAT compatible with Raspberry Pi and similar SBCs
It is purpose built for use with AqualinkD and allows you to easily connect an SBC to the Aqualink Serial bus

• Communication with the Pi happens over pins 8/10 for TX/RX
• If sourcing power from Aqualink's Serial bus, the board can provide 5v power up to 3 amps to power itself and the connected Pi (provided the Serial bus can deliver ~3 amps of current)
• The board has the same footprint as a Raspberry Pi Zero but also works on full size Pi boards like the Pi 3, 4, 5, etc. Usage with boards other then the Pi Zero form factor usually requre a different style connector for the Serial/Power connection. Vertical style connectors with a 3.50mm pin pith work.
• Two sets of 3.50mm mounting holes for the green Serial/Power connector allow for several connector options (horizontal flush/horizontal offset/vertical)

1. Pricing and availability for prebuilt boards can be found here
2. DIY - Follow the instructions on the DIY_JLCPCB.md page
   (Read the update on the top of the linked page about tariff impacts to USA)

1. Run raspi-config with sudo: sudo raspi-config
2. Navigate to Interface Options
3. Navigate to Serial Port
4. Select No when asked if you would like a login shell to be accessible over serial If you skip this step, aqualinkd will not work
5. Select Yes when asked if you would like the serial port hardware enabled
6. Select Ok
7. Exit raspi-config
8. Reboot
9. Edit aqualinkd.conf with sudo: sudo vim /etc/aqualinkd.conf
10. Set the serial_port variable to use Serial0: serial_port=/dev/ttyS0

1. You may need to adjust the rs485_frame_delay variable in /etc/aqualinkd.conf. This was not required for my setup but one user reported he needed to set: rs485_frame_delay=10

• Some SBCs like the Radxa Zero 3W, Orange Pi Zero 2W and similar have the debug serial console enabled on GPIO pins 8/10 in their images. Serial communication will not work in this configuration and the debug serial console needs to be disabled
• The Radxa Zero 3W board is supported with detailed instructions here