I still think of one idea within OpenSprinkler Unified Firmware applicable to all versions OSPi/ BBB / HW Sprinkler – use I2C bus supporting circuitry (such as ADC, pulse counter, etc …) then it will not matter whether the hardware version has pins. If I2C IC is mounted and connected in to FW as plugin (circuit would I2C injected as a plugin). But it’s just a thought. Once again, thank you for the work and effort you devote to the project.
example wind plugin: http://www.pihrt.com/elektronika/298-moje-raspberry-pi-plugin-prutokomer