Final Project Day to Day¶

This is an outdated page of my progress on my final project. Please read Final Project : FabSprout

I keep it just to show the evolving process.

Seed sprouted have many qualities for nutrition, a lot of vitamins and some seed like the Alflafla are nutritious. The seed sprouting is an ancestral food in many culture.

First sketch¶

Basically, you just need water and sun. And you want to avoid moisture. I want to build a smart automatic sprouter.

I’ll build an enclosure to keep the mist and the warm generated by the seed. It has to be translucent, the seed needs a small amount of light. I’ll have a system to add the water for at least 3 days and a way to get the water back.

The humidity sensor will confirm that their is mist when the fogger is in action (in case the system run out of water). Then monitor the decrease of humidity to feed back more fog following the growing cylce of the seeds. The light sensor will monitor the ambiant light, normally daylight, it’s one of the few clock in nature. I’m also curious about the influence of artificial indoor light. Temperature is one of the parameter. Some seeds need a certain temperature, if it’s hotter, the growing time is faster. If it’s too hot the seed will die. If it’s too cold the seed is in dormancy.

Common problem in Agriculture are : dust, moisture, mud, rain, wind and sun.

What I’d like to explore with this project : differents way to build things that can resist to moisture. I think I’ll create a mold for the enclosure then vacuum form the enclosure (it has to be water resistant and compatible for food). But maybe I’ll discover other way to waterproof 3d printing. For the electronics, I’ll have to find some way like epoxy to protect from moisture .

first CAD representation¶

In my 3rd week, I’ve used Fusion360 to design the lower part of my final project with the idea of having a better visual of it.

With an intensive rendering

What materials and components were used? Where did they come from? How much did they cost?¶

For the differents plastic parts, I think PET could be a good material, it’s food safe. Some others part will be directly 3d printed.

Object	Material	Price	link
top cover	PET material	? 4€	custom CAD files
bottompart	PET material	? 4€	custom CAD files
tray	PET material	? 4€	custom CAD files
Mist Foger (piezzo electric element and 24V DC)	bought from China	10€	https://www.aliexpress.com/item/2Pcs-With-Plug-Or-No-Plup-Industrial-Incubator-humidifier-Ultrasonic-Mist-Maker-24V-Nebulizer-Atomizer-Head/32821355140.html?spm=a2g0s.9042311.0.0.7ac54c4d1Jyhep
NDS355AN	n-Mosfet SMD	0.60€	https://www.digikey.com/product-detail/en/on-semiconductor/NDS355AN/NDS355ANCT-ND/459000
VEMT3700	PhotoTransistor	1€	https://www.digikey.com/product-detail/en/vishay-semiconductor-opto-division/VEMT3700-GS08/VEMT3700-GS08CT-ND/1681484
SHT30	temp/humidity sensor	4€	https://www.digikey.com/product-detail/en/sensirion-ag/SHT30-DIS-B2.5KS/1649-1009-1-ND/5872292
ESP32-WROOM	MCU	<5€	https://www.digikey.com/product-detail/en/espressif-systems/ESP32-WROOM-32/1904-1010-1-ND/8544305
planB : another microcontroler	microcontroler	<5€
Resistor	SMD component	1€

What processes were used?¶

3D printing, CNC 3D milling, vacuum forming, 2D PCB milling, electronic design, electronic production, input/output, automation.

What are the implications?¶

A cheap way to grow vegetables with high values in vitamins.

Options in Design¶

My Optimistic option is to use an ESP32. And to build a small web interface to enter parameters like the kind of Seed , the amount of water and water cycles, the expected duration of sprounting.

But the ESP32 could be really complex.

My project is to make a sprouter : the different pieces and an electronic system that launch the misting.

So my planB is to used a more simple micro-controller, it could be based on a simpler version with fixed interval of time.

Electronics design and production, microcontroller interfacing and programming, system integration**¶

The humidity sensor will confirm that their is mist when the fogger is in action (in case the system run out of water). Then monitor the decrease of humidity to feed back more fog following the growing cylce of the seeds. The light sensor will monitor the ambiant light, normally daylight, it’s one of the few clock in nature. I’m also curious about the influence of artificial indoor light. The seeds normally does not have the same activity under nigtlight/daylight and will not consume the same amount of water. Temperature is one of the parameter. Some seeds need a certain temperature, if it’s hotter, the growing time is faster. If it’s too hot the seed will die. If it’s too cold the seed is in dormancy. The seeds release a small amount of temperature during certain phases of the growing.

If combine properly those input and output can be optimise to make the seeds grow faster or to make them more vigourous.

The piezzo electric element of the fog maker controlled by the mosfet.

2D and 3D design, additive and subtractive fabrication processes¶

On Week 03, I design a first version with CAD tools.

I will certainly build a mold then vacuum formed with alimentary plastics.

The render version :

The bottompart :

The tray

The top cover :

A render of the evolved version :

An inside part will contain the electronics, the sensors, the low power wire, the water infill tube… It will be 3D printed, the shape would be too complex for vacuum forming.

Milling a mold¶

Milling of a mod to vacuum form.

The fixture for the CNC are not big enough. I had with a colleague built really big one to be able to mill a big piece of wood that we found outside (part of a roofing that had fallen).