Air Conditioner Controller - Case Study
The client required an ESP32 Smart AC Controller designed to modernize climate control systems and integrate seamlessly into the smart home ecosystem. The primary objective was to transform traditional units into a smart air conditioner, enabling users to remotely monitor and adjust ambient indoor temperatures from anywhere in the world. To maximize user comfort and operational efficiency, this battery-powered controller needed to support localized scheduling to maintain optimal living conditions autonomously. A critical commercial requirement was interoperability, ensuring the device could seamlessly participate in advanced home automation scenarios. This allows the system to harmonize with other peripheral devices—such as automated window blinds and intelligent lighting—to facilitate unified, user-defined ecosystem profiles like coordinated day and night modes.
Project Context
The air conditioner controller was developed as a highly specialized, power-optimized standalone edge device designed to retroactively modernize legacy climate control units. At its core, the ESP32 microcontroller serves as the central processing unit, chosen for its integrated Wi-Fi capabilities and flexible low-power modes. A primary engineering requirement of the hardware was its power architecture. This controller is driven completely by a 4x AA battery pack.
This constraint necessitated aggressive hardware-level power management, employing a high-efficiency low-dropout (LDO) linear regulator and optimized deep-sleep circuitry to maximize battery longevity without sacrificing network responsiveness. To bridge the gap with traditional air conditioning units, the custom PCB integrates an infrared (IR) transmitter and receiver array, allowing for universal command blasting and active remote control signal emulation. Precise environmental feedback is continuously monitored via an external, cable-mounted air temperature and humidity sensor (such as the ENS210 or AHT20) communicating over a dedicated I2C bus.
From a software perspective, the firmware framework was built from scratch as an independent codebase tailored for extreme low-power duty cycling. The device utilizes the native ESP32 Wi-Fi Mesh protocol to act as a peripheral end-node, transmitting ambient climate telemetry and receiving system commands through the local mesh network. Concurrently, it hosts an autonomous, localized 24-hour scheduling engine running directly on the ESP32 microcontroller. This ensures that user climate profiles, target temperatures, and broader multi-device scenarios (such as day and night transitions) execute seamlessly at the edge, even during complete cloud or local network outages.
Project Context
The air conditioner controller was developed as a highly specialized, power-optimized standalone edge device designed to retroactively modernize legacy climate control units. At its core, the ESP32 microcontroller serves as the central processing unit, chosen for its integrated Wi-Fi capabilities and flexible low-power modes. A primary engineering requirement of the hardware was its power architecture. This controller is driven completely by a 4x AA battery pack.
This constraint necessitated aggressive hardware-level power management, employing a high-efficiency low-dropout (LDO) linear regulator and optimized deep-sleep circuitry to maximize battery longevity without sacrificing network responsiveness. To bridge the gap with traditional air conditioning units, the custom PCB integrates an infrared (IR) transmitter and receiver array, allowing for universal command blasting and active remote control signal emulation. Precise environmental feedback is continuously monitored via an external, cable-mounted air temperature and humidity sensor (such as the ENS210 or AHT20) communicating over a dedicated I2C bus.
From a software perspective, the firmware framework was built from scratch as an independent codebase tailored for extreme low-power duty cycling. The device utilizes the native ESP32 Wi-Fi Mesh protocol to act as a peripheral end-node, transmitting ambient climate telemetry and receiving system commands through the local mesh network. Concurrently, it hosts an autonomous, localized 24-hour scheduling engine running directly on the ESP32 microcontroller. This ensures that user climate profiles, target temperatures, and broader multi-device scenarios (such as day and night transitions) execute seamlessly at the edge, even during complete cloud or local network outages.
ESP32 Smart AC Controller Hardware Stack
Firmware Stack
Air Conditioner Controller Time Estimates
The following table outlines the estimated development hours across each project milestone, from initial analysis and custom PCB design through to physical validation of the hardware platform.
| Stage | Min h | Max h | |
|---|---|---|---|
|
Component selection |
20 |
26 |
|
|
Schematic drawing |
22 |
28 |
|
|
Component package drawing |
10 |
14 |
|
|
PCB routing |
32 |
40 |
|
|
Production files & component ordering |
12 |
16 |
|
|
Assembly & Hardware Testing |
38 |
42 |
|
|
Total Hardware time |
134 |
166 |
|
|
Wi-Fi communication (Node setup & BLE provisioning) |
40 |
60 |
|
|
ESP32 WiFi Mesh communication (Node mesh integration) |
48 |
72 |
|
|
Cloud MQTT broker communication (Payload state machine) |
32 |
48 |
|
|
Measure air temperature and humidity (Sensors data filtering |
24 |
56 |
|
|
Handle infrared communication (IR protocol parsing & blasting) |
24 |
56 |
|
|
Bussiness logic – Mobile App communication via MQTT broker |
224 |
256 |
|
|
Bussiness logic – Schedules |
104 |
136 |
|
|
Battery power consumption optimizations |
104 |
136 |
|
|
Total Firmware time |
600 |
820 |
|
|
Quality Assurance |
72 |
96 |
|
|
Project Management |
72 |
96 |
|
|
Total estimated time |
914 |
1232 |
Note: To the final total project estimated time might be added up to 15% of time for risk assessment.
