[DESIGN] - Humidification

[JLefebvre55]

Completion is tracked in the linked PR.

Design Scope

Design an ultrasonic mesh nebulizer humidifier.

Purpose

The purpose of the humidification system is to generate dry water vapour, increasing the relative humidity of the growth environment on demand.

Function

Inputs:

• Power
• RO Water
• On/off control signal

Outputs:

• Dry water vapour

Method

Process:

1. Air is circulated throughout the environment for humidity homogeneity
2. Relative humidity is measured, sent to automation
3. Automation activates humidification system if below dead-zone

Features

Each feature should be added to relevant BoMs and CADs where applicable. Design decisions should be well-supported using relevant research and calculations, and should be documented in the Solution Overview. If a feature is complex enough, create a new issue for it using this template, and tag it here.

• Circulation Fans (part of [DESIGN] - Air Thermoregulation & Circulation #122)
• Humidity Sensors (integrated with Temperature Sensors in [DESIGN] - Air Thermoregulation & Circulation #122)
• Ultrasonic Humidifier
  • Water Tank
  • Piezoelectric Disc (mesh vs ceramic?)
• [DESIGN] - Mesh Nebulizer Driver Circuit #129
• Bang-Bang Control System

Validation

Must output clean, dry vapour.

Verification

List any applicable metrics with criteria/constraints:

1. Max humidity output (maximize)

[JLefebvre55]

Background

Reference design:
https://www.youtube.com/watch?v=aKhPj7uFD0Y
https://www.youtube.com/watch?v=OOZi3QnnDCo

Some potential discs:
https://www.steminc.com/PZT/en/mist-generation-transducer

ToDo

• Determine max/min desired environment relative humidity
• Determine vapour output target to reach extremes in 120sec
• Determine vapour droplet diameter
• Select Piezoelectric Disc
• Design Water Tank
• [DESIGN] - Mesh Nebulizer Driver Circuit #129
• Humidity Sensor and Control System
  • Select Temperature Sensor SHT31-D Breakout by Adafruit
  • Bang-Bang Control Loop