So the primary components of an aeroponics-based vertical farm:

LIGHTING

LED-lighting array comprising LEDs of varying wavelengths

NB. needs to be isolated from the plant and root zones, since we don't want the electronics to get wet! Perhaps with plastic or glass as a barrier.

PLANT-ZONE

Mounts for the plants, with supply of required gas mix. Sensors specific to this zone.

ROOT-ZONE

Here the roots are exposed to components which will deliver water and nutrients and required gas mix. Sensors specific to this zone.

WATER-SUPPLY

In order to supply water droplets of required size (i.e. 5-50 microns per [need study ref is this the best size] we would need a high-pressure delivery system for the water. This is I think to most complex component, and has a few different possible designs (each with positives and negatives to investigate)

• Water and nutrient reservoir 
• High-pressure ~100psi water-pump. This would be an off-shelf component of the system
• Filtration upstream or downstream of the pump? Or is it actually upstream of the reservoir?
• Pre-pressurized accumulator tank. The reason being the pump will take some time to get to required pressure, so this prevents us hitting the roots with droplets that are too large. This is one of the components I'm a bit unhappy with. Since off-shelf will mostly be steel, and if they go over their pressure tolerances (e.g. pressure-relief valve fails, poor maintenance, problems with pump) they may explode! The off-shelf tanks can also be made from nylon, and I have heard reports of DIY tanks being built from PET bottles. So this bit will need careful investigation.
• Solenoids for switching the spray nozzles on/off
• Spray nozzles with holes of required diameter. These can be purchased easily, or can be 3d printed I guess?

There is actually an alternative to using high-pressure for producing droplets of required size! Loosely referred to as fogonomics. So would use ultrasonic atomizers (e.g. https://www.amazon.com/dp/B073322QF8/ amazon link) to get required droplet size from a water reservoir. Perhaps with wicks from the water reservoir to the atomizer which could be then mounted in the ROOT-ZONE?  An issue with this is difficulty of cleaning the atomizers, and would the nutrients get through them ok? It's kinda easy to screw off a spray nozzle and clean it manually. But these not so much. There is an idea to automatically clean them I have noticed, and will investigate. The positives of this method are being we don't need to worry about the pre-pressurized accumulator tank anymore and don't need a high-pressure pump.