The garden is a two-part experiment:
- The upper tank is an ebb-and-flow grow bed which fills and empties on a regular schedule.
- The lower tank is a reservoir and aeroponics grow bed, using ultrasonic misters to create a high humidity environment for the plant roots.
It is built with the following goals in mind:
- Error-tolerant - If the software should ever fail, it should be impossible to cause any damage to our house (eg. flooding). This doesn't mean the plants themselves won't die from a lack of water.
- Simple - Minimize the number of hardware parts
- Modular - Must be able to be disassembled
- Quiet - It is located in our living area, so it must be quiet
- Moniterable - Equipped with lots of sensors for monitoring system health and operation.
Error-Tolerance is achieved by using two reservoirs of the same size. If the level sensors fail and the pump keeps pumping, eventually they will run out of water and thus it is impossible to flood the room. Additionally, errors will be detected by software and the user will be alerted to any possible issues with the sensors/pumps/etc.
Simple/Modular - It is built out of stuff you can get from the garden store or Amazon. There is only one pipe (and one pump) connecting the two reservoirs, so there is minimal plumbing.
Quiet - The setup is almost silent due to the use of a DC brushless pump and ultrasonic mister. It's so quiet I can't even tell when it has gone through a pump cycle!
Sensors - We need sensors to monitor system operation (water levels, water flow, humidity, etc.) and system health (pH, EC/TDS, temperature, etc.).
Monitoring - Will be presented with a Raspberry Pi using a rich web page to show graphs of all the vital sensors. As a bonus the Raspberry Pi will capture timelapse photos of the growing process. System control is done by a separate microcontroller (Currently an Arduino Pro Mini, but I may move to something more powerful)