17. Applications and Implications¶
What will it do?¶
Micro-greens grower, or Yet Another growing system for Controlled Environment Agriculture in the home.
A small table top device suited for a domestic setting that will be used as a teaching tool to demonstrate the principles of growing indoors. A small device that will primarily be used to grow small edible plants, ie micro-greens. Probably radish.
The system has three functions. An LED panel made up with horticulture LEDs in Red and Blue, a fan for moving air and a peristaltic pump for watering. There will be a control panel of sliders buttons and switches that lets you manage the timing overall, and amount of each of the three controlled elements. The controls are designed to be analog.
Who’s done what beforehand?¶
From Neils favourite example onwards the examples in the Archive are almost endless here’s a sampling from the first page of searches for Hydroponics and Aquaponics:
ari-vuokila/finalProject fablabaalto/students/294 fablabbottrophrw/students/64 sachin-salim/finalproject nicolas-newton/Week20 heodore-warner/Final%20Project
In the broader industry millions of research dollars and yen are poured into large scale systems every year. A commercial industry is set up to supply the needs of a growing market.
In the domestic setting there are many competitors:
Curated articles: best-home-hydroponics-kits-gardening best-indoor-herb-garde
Example systems (countertop and appliance type systems) £5 bracket: naturalcollection
£100 bracket: clickandgrow
£200 bracket: itality4life
£400 bracket clickandgrow
Unknown bracket: urbancultivator indoor-vegetabl
All the above are closed systems. We aim to learn from this project so that in the future we might produce open systems. First the teaching tool.
What will you design?¶
The system will include a Grow light, Fan for moving air and Pump for moving water.
Here’s a mock-up of the form factor:
In the mock-up you can see the fan and the pump motor in there being the major constraints on form factor.
For the three major subsystems:
- LED panel is a PCB with LEDs and limiting resistors suspended over the plants. These will be witched on and off by the main timer board.
- The Fan in managed by it’s own board that will control the fan speed and it’s optional connection to timer board.
- The Pump is managed by it’s own board that will control the amount of water dispensed. The breakout for a TMC2208 may be separate depending on the final form factor of the enclosure.
The enclosure is intended to be a wood laminate composite.
Where will come from?¶
We have historically operated our lab with a Just In Time procurement. With some great suppliers, we could make an order late in the day and have parts on our desk the following morning. In the current supply chain climate that is no longer possible. As a lab that is slowly bootstrapping Fab Academy, aiming to be a node, it’s time to stock the inventory. This will be addressed this summer with an student intern.
In the mean time our primary suppliers are:
- Electronics RS and Farnell with occasional orders to Mouser for those things that only come from a Texas warehouse.
- My veneers have come from the Wood Veneer Hub
- Sheet timber from a local firm Huws Gray
- Motors from ooznest
- Amazon.co.uk for everything else.
How much will they cost?¶
Approximate costs of largest component (Precise BOM to follow):
| Item | Cost |
|---|---|
| Laminates | £20 |
| Stepper | £40 |
| Fan | £10 |
| Potentiometers | £5 |
| Micros | £5 |
| Misc components and wiring | £20 |
| Fastenings and Bearings | £10 |
| Total | £120 |
What parts and systems will be made?¶
- Enclosure.
- LED panel.
- Driving electronics.
Architecture, some notes¶
Above is the plan for the electronics. For an example of one of the completed parts see Output Devices week
As one of the goals of the project is to make a kit of parts I’ve been aiming to produce a collection of small single purpose boards. They, and their interconnections are illustrated above.
Simple signals¶
Inspired by little bits, I’ll be aiming to combine parts with very simple signals, in most cases a HIGH/LOW will do the trick.
In the example illustrated, the timer unit has a simple on/off signal that will directly drive the enable pin on the LED panel. The other drivers will have the ability to selectively get in sync with the LEDs or act independently, where the other enable input could either be, always on or always off. A three way toggle is also an option.
Specifications¶
POWER:
- 12V in, master switch, distributed to all other boards.
TIMER:
- Two slide pots, start and stop time
- Button
- Indicator LED
- Signal out
The intention is to have two sliders, one sets the on time the other the off time. They would also be used in combination with the button to set the clock, where a feedback/ack would be available with the LED. The output signal is used to drive the enable on other boards.
LED:
- Red and Blue horticulture LEDs
- 12V in
- En signal
- Slide pot for dimmer
FAN:
- 12V in
- En signal
- Slide pot to set speed
- Near silent Arctic PWM fan specified for constant use.
PERISTALTIC PUMP:
- 12V in
- En signal
- Slide pot to set pumping minutes/period. Water volume.
- Stepper motor with a Trinamic silent stepper driver.
What materials and components will be used?¶
- Main form of the enclosure will be made from wood composites.
- Major outputs: Horticultural LEDs, Stepper Motor, Fan
- Inputs: Slide potentiometers.
- 12V ‘wall wart’ to supply the power.
What processes will be used?¶
| Skills | Task |
|---|---|
| Computer Aided Design | Form and mold design. Iconography for control panel. Pump parts. |
| Computer Controlled-Machining | Large format milling for mold making |
| Wildcard Week | Bag-press composites. |
| Electronics Design | Circuit Design |
| Electronics Production | Soldering. Isolation milling for PCB manufacture. |
| Computer Controlled Cutting | Laser cutting of cut-outs in enclosure and small ancillary parts and preparing laminations. Pump parts |
| 3D Scanning and Printing | Junctions and linking parts |
| Bench work and hand tools. |
What questions need to be answered?¶
- Can we make aesthetic forms for device enclosure that don’t look like they came off the laser cutter?
- How do we drive the Trinamic stepper driver?
- Can we make nice junctions between materials?
How will it be evaluated?¶
Before the end of the June will it have grown something green? I’m allowing some time for a plant to grow once I’ve completed the device for the presentation mid June.