Simple hydroponics system

A Raspberry-Pi based controller for a hydroponics system, turning the lights on and off at set times of day and running the pump every hour.

Hardware

Parts list

1. A pair of relays for controlling the lights and pumps. The easiest and safe (but certainly not cheapest) solution is to get two "IoT Relays" from Digital Loggers Inc.
2. A pump for aerating the water [and tubing---how much, which did we get?].
3. Lamps for illuminating the plants. We used a 5 meter Toogod red:blue 4:1 LED roll, which gives 2.5 meters of LEDs (about 30 W) per container. You will also want two packs of the 15 cm connectors for these.
4. IKEA TROFAST cabinet (yes, the toy storage one), to serve as frame, with two matching shallow storage boxes to hold the water, two lids to hold the plants, and two shelves for adjustable-height lighting.
5. Baskets for the plants.
6. Clay pellets.

Tools

1. A 2.75" hole saw (for cutting holes in container lids).
2. Soldering iron and solder (for soldering the LED strips).
3. A utility knife (for stripping rubber insulation from the LED strips).
4. Glue for the LED strips. The Toogod strips come with adhesive on the backside, but it is not sufficiently strong to hold their weight for more than a few hours.

Assembly

1. Assemble the IKEA cabinet.
2. Cut seven 2.75" holes in each container lid. This is most easily done using a hole saw.
3. Wash the pellets.
4. Cut the LED roll into 14 strips of 7 segments each. (You will have two segments leftover. If you cut 7 strips, then 2 segments, and then another 7 strips, you will not have to cut through the manufacturer's solder, which appears every 10th segment.)
5. Glue 7 LED strips to the backside of each of the TROFAST shelves and connect them in series using the connectors. Solder the connectors. (The connectors appear to work without solder at first, but in our experience fail after a couple of days.)

Figures needed

1. Container lid with holes cut.
2. Assembled lighting panel, with at least one connector open to show solder job.
3. Assembled lighting panel, showing the "serial" nature of the circuit.

Software

There are two versions of the software.

1. The basic version runs the pump and lights on a schedule, but does not provide any convenient interface for suspending operation.
2. The web app version provides a Flask web application, accessible from the browser, which allows you to turn off the lights and stop running the pump for a period of time ("quiet mode"), and then resumes regular programming.

Dependencies

The basic version depends only on apscheduler, the Advanced Python Scheduler.

The web app version requires the apscheduler and Flask.

Installation

To have access to the GPIO, we need to run the application as root, so all of the packages must be installed into the sudo Python (rather than the user Python or some virtualenv).

1. Install Flask via sudo pip install Flask.
2. Install the Advanced Python Scheduler via sudo pip install apscheduler.
3. Clone this repository.

Usage

After setting the values in config.py, run either,

1. sudo python main.py & for the basic version, or,
2. sudo python webapp.py & for the web app version.

Don't forget to do disown -h %1 to keep the job running after you log off.