Hello fellow Particulates,
I am a hardware guy and my firmware skills are limited such that I could, at best, be called a bit banger. Never the less, I have been toying with the idea of making a greenhouse controller for some time now. Basically, the controller is just a collection of inputs and outputs (both analog and digital). I am in the process of spec’ing out a multifunction I/O board the Photon will plug onto.
The controller I/O will comprise of:
Optically isolated digital inputs (120V tolerant)
Digital outputs (relay 250V / 10A)
Digital outputs (SSR for 24Vac irrigation valves)
Temperature inputs (10K thermistor)
High CM analog inputs (0-10V)
Analog outputs (PWM 0-10V)
Chopper drive (variable speed for single phase induction motor/fan)?
The controller will measure and / or control:
Water flow meter
Solenoid valves for misting and drip watering
Damper control with position feedback
Lighting based on sunrise / sunset times
Optional OLED display?
Optional water conductivity?
I know the Photon lacks the I/O but I can add a CPLD with an I2C slave instantiated in it to act as an GPIO expander. The CPLD can also have the flow meter totalizer as well as a solar radiation integrator (using the PAR sensor). All inputs will be ESD protected in accordance to IEC/UL 60730. The board will fit into an industry standard DIN enclosure with plug in style connectors.
Why am I posting this? There is a lot of commonality between greenhouses, aquariums, terrariums and aquaponics. Perhaps this controller can be leveraged to other application areas with a firmware change and the right combination of I/O.
Are there others out there that could use this controller for themselves?
Are there any additional measurands that should be included?
I am happy to share all the design files. Heck, I will even give you a board if someone wants to help on the firmware side!
More heads are better than one …. right?