Blueprinting the Farm-Proof ESP32 Sensor Node

Author: Reynan M. Maglimolo | Project: Uni-Farm Hub

In my last DevLog, I proved that the Uni-Farm Hub backend works flawlessly. The PHP server can catch simulated JSON data, write it to the MySQL database, and trigger a Twilio SMS emergency alert to my phone. The brain is officially online.

Now, it is time to build the hands. We need physical hardware inside the broiler house to read the actual environment. But a commercial poultry house is an incredibly hostile environment for electronics. Between the microscopic dust from the feeds, the high humidity, and the highly corrosive ammonia gas from the manure, a standard computer board will short-circuit in weeks.

Here is my blueprint for building an affordable, open-source, and "farm-tough" IoT sensor node.

The Core Components

Commercial agricultural sensors cost tens of thousands of pesos. By sourcing individual open-source components, I am targeting a build cost of under ₱1,500 per node.

• The Brain: ESP32 Microcontroller. I chose the ESP32 over the older Arduino Uno or ESP8266 because it has built-in Wi-Fi and enough processing power to handle secure HTTPS requests directly to my server.
• Temperature & Humidity: DHT22 Sensor. Essential for monitoring heat stress during the brooding phase. The DHT22 offers much higher precision than the cheaper DHT11.
• Air Quality: MQ135 Gas Sensor. This is critical. The MQ135 is sensitive to NH3 (Ammonia). High ammonia levels blind the birds and cause respiratory failure. This sensor is my early-warning system.

Designing for Durability

Because of the corrosive ammonia and heavy dust, I cannot just leave the wiring exposed on a breadboard. My design requires two protective measures:

First, the entire ESP32 and power supply will be sealed inside a heavy-duty IP65 waterproof junction box. Second, I will be using a silicone conformal coating—a special waterproof liquid brushed directly onto the exposed metal solder joints to prevent the ammonia gas from eating away at the copper.

What is your go-to method for weatherproofing outdoor electronics? Share your tips in the discussion below!