Comparing Single Board Computers for RootMaster
When building an open hydroponics system like RootMaster, selecting the right single board computer (SBC) is crucial. The SBC serves as the brain of the operation, controlling sensors, pumps, and providing connectivity. This post compares four candidates I’ve been testing for the project.
Project Requirements
For RootMaster, we need an SBC that:
- A form factor similar to Raspberry Pi Zero with a 40-pin connector
- Offers sufficient processing power for sensor data collection
- Provides wireless connectivity
- Able to run the third party application Mycodo
The Contenders
Raspberry Pi Zero 2W
- Processor: Quad-core ARM Cortex-A53 @ 1GHz
- RAM: 512MB
- Storage: SD card
This is the most accessible of the boards tested, though it is also the least powerful. RootMaster support is integrated upstream in Raspberry Pi OS, so getting started is straightforward (see this upstream PR). However, it is not fast enough to run Mycodo.
Banana Pi M2 Zero
- Processor: Allwinner H3, Quad-core Cortex-A7 @ 1.2GHz
- RAM: 512MB
- Storage: SD card
Same RAM configuration as Raspberry Pi M2 Zero so not optimal for running Mycodo. Unfortunately there seems to be a bug in the Allwinner SPI driver which makes the CANbus interface hang when stressed. Since CAN communication is critical for OpenHydroponics this is a blocker for using this board with RootMaster. If this bug is fixed then this is a good contender with Raspberry Pi Zero 2W.
Banana Pi M4 Zero
- Processor: Allwinner H618, Quad-core Cortex-A53 @ 1.5GHz
- RAM: 2GB/4GB
- Storage: 8GB/32GB eMMC + SD card
This is a more powerful version of the Banana Pi M2 Zero. More RAM and a faster processor makes this a great board that can also run Mycodo. With the onboard eMMC is it possible to run the software without the need for an SD card. Unfortunately the same SPI bug as in Banana Pi M2 Zero is also found in this board making it unfit for OpenHydroponics.
Radxa Zero 3W
- Processor: Rockchip RK3566, Quad-core Cortex-A55 @ 1.6GHz
- RAM: 1GB/2GB/4GB/8GB
- Storage: 16GB/32GB/64GB eMMC + SD card
Plenty of RAM and onboard eMMC. Since this board is using a Rockchip processor instead of Allwinner (as found in the Banana Pi boards) it is not affected by the same bug found in the Banana Pi. The CANbus is stable and is capable of running Mycodo. This is the clear winner of the tested boards.
Conclusion
The Radxa Zero 3W is the best choice for RootMaster, offering a powerful processor, ample RAM, and stable CANbus communication. The Banana Pi M4 Zero is a close second but is currently unusable due to the SPI bug. The Raspberry Pi Zero 2W is a good option for simpler projects but lacks the power needed for Mycodo. The Banana Pi M2 Zero is not recommended due to its SPI bug. The SBC landscape is constantly evolving, and I will continue to test new boards as they become available. If you have any suggestions or experiences with other SBCs, please share them in our Discord community.