OpenAg Wiki Archive

Archived Contents from the original OpenAg Wiki (snapshot on Apr 8, 2020)

The archived wiki only includes information up the v3.0 version of the PFC-EDU, and is here for preservation purposes. You can find resources about the latest version of the PFC v4.0 on the Personal Food Computer resources page.

MVP 1.0

The MVP PFC (Minimal Viable Product) is a minimalist Personal Food Computer developed by OpenAg Community members on the OpenAg Forum (Note: Forum not available), in response to a call placed by MIT Open Agriculture Initiative’s Director Caleb Harper to build the “first truly community derived device” for OpenAg.

For a quick overview, see the promo video

The OpenAg community’s goal is to build something for around $300 (US) that can produce significant research results with minimal investment and skill. The MVP PFC allows for control and research around:

  • Nutrients
  • Light (photoperiod)
  • Temperature

The MVP PFC has the following main parts:

Enclosure

The standard enclosure is a PVC and foil box.

Brain

The brain is based around a Raspberry Pi and Python code, with cron used as the scheduler. The latest code is located in Github.

Sensor data is currently logged to a flat file on the Pi’s SD card, as well as optionally being stored in CouchDB (on the Raspberry). By using CouchDB, the data is available over the internet. Work is in process to modify the existing PFC (Personal Food Computer) UI to access the MVP data. While both the MVP and PFC use CouchDB, they use different databases with different data structures.

Camera images are stored in a directory as jpg files.

Lighting is standardized on the GE Brit Stik LED (100w equiv, daylight). We are still researching whether two or four are needed. A quick experiment revealed that by removing the end covering and revealing the LED, that the light intensity could be significantly increased.

There are two fans. One is always on for circulation, and the other is thermostat controled for exhaust ventilation.

An Adafruit SI7021 temperature/humidity sensor and USB camera are the only standard sensors; though there are open GPIO pins and two relays available for future or custom expansion.

Reservoir

The current system is hydroponic, the reservoir is a bus tub with an air-pump and stone. Plants are started in rockwool and placed into net pots in the reservior lid. All chemistry (EC and pH) are done manually. There is active research in converting the MVP into an airoponic system. While it will cost a bit more (for the pump) it will eliminate the need for much of the chemistry.

Resources

Check out our promo video for a quick summary of how to get started

1. Assemble supplies Order parts from the Bill of Materials (BOM) Verify you have all required tools on second tab of BOM, if you are missing any, order them.

2. Machine parts into ready to assemble Prepared Parts: Prepared Parts Documentation

Be aware there are some inconsistencies between video and written documentation. When in doubt: Follow the written documentation as it is updated to current BOM.

3. Build Enclosure: Watch Enclosure Subassembly Video Enclosure Documentation

4. Build Top Panel or “Brain” assembly: Watch “Brain” Subassembly Video Brain Documentation

5. Build MVP Software Stack on SD card & Raspberry Pi: Software Documentation Software Installation Guide on GitHub

6. Complete Final Assembly Final Assembly Documentation

7. Germinate seeds in Rockwool, balance your PH, and get growing! Operational Documentation

8. Get involved on the forums, show us your build and ask questions: Frequently Asked Questions

9. Hacking the MVP (Python code architecture)

Additional Help

Alternate Builds and Materials

These builds are not the standard MVP, but alternative designs from the community. Listings here are for information without any implied recommendation or evaluation.

MVPs in Schools