13. Applications and implications

Assignment

Propose a final project masterpiece that integrates the range of units covered, answering:

  • What will it do?
  • Who’s done what beforehand?
  • What will you design?
  • What materials and components will be used?
  • Where will come from?
  • How much will they cost?
  • What parts and systems will be made?
  • What processes will be used?
  • What questions need to be answered?
  • How will it be evaluated?

Your project should incorporate 2D and 3D design,

  • additive and subtractive fabrication processes,
  • electronics design and production,
  • microcontroller interfacing and programming,
  • system integration and packaging

What will it do?

  • Pump water to feed plants
  • Stop pumping when the water tank is empty
  • Start pumping when the water tank is filled

Who’s done what beforehand?

Most of the hydroponics designs that I have seen on the Internet are based on a plastic tank, or PVC pipes assembly.

This website shows the diversity of existing DIY hydroponics systems.

My favourite design is the #10, with plastic bottles. But the structure is not rigid and it has to be wall-mount. I want to design something easier to move from a place to another.

What will you design?

  • 3D print model for the planters. I will design it in Openscad so it dimensions can be adapted easily
  • PCB for pump control and water sensor connection
  • Drawing for cutting the bottle that contains the electronics
  • Drawing of a board to screw the electronics in place
  • Drawing for cutting the bottles caps

What materials and components will be used?

  • A wood pallet
  • 2 empty plastic bottles (1.5l)
  • A water pump
  • An AC-DC converter (220v → 5v)
  • A microcontroller board
  • A low-voltage interface for the water level sensor
  • A high-voltage interface to control the pump
  • 3D printing filament for the planters (I will try PLA and PET-G)
  • Flexible PVC tubing
  • Plastic connectors that fits in the PVC tubing
  • Insulated wires for the water level sensor
  • A lot of electric connectors
  • Hydroponic media (clay balls or coconut fiber)

Where will come from?

These materials are re-used, I found it in trashes :

  • A wood pallet
  • 2 empty plastic bottles (1.5l)
  • A water pump, from a defect Senseo coffee machine
  • An AC-DC converter (220v → 5v), from an old cellphone charger
  • PTFE insulated wire

These materials are from the lab stock :

  • ⅛” ID - ¼” OD flexible PVC tubing
  • 6mm ID - 8mm OD flexible PVC tubing
  • 3D printing filament (PLA/PET-G)
  • Electronic components
  • Electrical connectors and jumper wires

I only bought the clay balls from a local store named Brico.

How much will they cost?

Clay balls can be found in any gardening store for less than 8€.

All the other parts were already in the lab, so I got it for free. Anyway, I listed the components in this table :

About the 3D printing filaments, I will try these :

What parts and systems will be made?

  • Two bottle caps
  • Planters
  • Two PCBs for the electronics
  • Two wood panels, to hold the bottles
  • A water level sensor
  • Water tubing connectors
  • Some flexible PVC tubing with drills, for water dripping

What processes will be used?

  • The bottle caps can either be laser-cut (in the original cap) or 3D printed
  • The planters will be 3D printed
  • The electronics PCBs will be cnc-milled
  • The wood panels will be laser-cut or cnc-milled
  • The water level sensor will be made by hand, from insulated wires
  • The flexible PVC tubing will be drilled with a Dremel tool.

What questions need to be answered?

The main questions are about protecting the setup from water leakage :

  • Are the 3D printed planters watertight ?
  • Are the 3D printed tubing connectors watertight ?
  • How should I seal the bottle that contains the electronics ?
  • How can I make a power entry that is suitable for outdoor use ?

How will it be evaluated?

The final setup needs to fulfill this checklist :

  • Electrical safety
  • Leak-proof water circuit
  • Pumping stops when water level is low
  • Pumping starts when water level is high