EarlyEar

Bovine Respiratory Disease (BRD) is the most economically significant disease in the cattle industry. By the time visible symptoms appear, the animal is already well into infection treatment is less effective and losses are higher. EarlyEar is a compact, solar-powered ear tag designed to detect the earliest physiological indicators of BRD: elevated temperature and reduced movement. The goal is to flag sick animals before symptoms are visible.

Development Roadmap

The Problem — Why BRD Is Hard to Catch Early

BRD accounts for over 70% of feedlot cattle illness and a significant portion of mortality. The challenge is that cattle mask illness instinctively and by the time a stockman visually identifies a sick animal, the infection has typically been progressing for 24–72 hours. Early treatment with the correct antibiotic is dramatically more effective than late intervention, but identifying that window visually at scale is nearly impossible.

The two most reliable early physiological indicators are a rise in body temperature above the normal range (~101–102.5°F) and a measurable drop in movement activity. An ear tag that monitors both continuously and flags deviations from an individual animal's baseline could push the detection window back by one to two days, enough to meaningfully change outcomes.

Hardware Architecture

Ear Tag Components

Base Station / Gateway

The gateway sits in the barn or pen and collects BLE data from all tags within range, logs to local SQLite, and handles alert logic and any wireless upload. A second ESP32-S3 SuperMini runs as BLE central scanning for tags — same board as the tags, which simplifies the codebase significantly.

Enclosure Design

The tag body needs to be compact enough to sit on the ear without causing irritation or snagging, rugged enough to survive a feedlot environment, and sealed against moisture and debris. The solar panel mounts on an angled bracket extending from the main body with the angle set so the panel faces skyward during normal grazing head position rather than straight up, improving charge capture throughout the day.

The bracket hang-off is the most structurally demanding feature. It's a cantilevered shelf loaded by the weight of the panel plus dynamic loading from head movement. Finite Element Analysis will evaluate stress at the bracket root and determine whether the printed geometry needs reinforcement or a revised angle.

Early concept sketch — tag body with angled solar bracket.

SolidWorks enclosure model — tag body and bracket geometry.

Solar Bracket Structural Analysis

The angled solar panel bracket is a cantilevered feature loaded by panel weight and the inertial forces from head movement. The bracket root, where it transitions into the tag body, is the primary stress concentration of interest. FEA in ANSYS Mechanical or SolidWorks Simulation will evaluate Von Mises stress and displacement under representative load cases to confirm the design can survive daily use without fatigue failure.

Planned Load Cases

• Static gravity — panel weight at full cantilever extension
• Dynamic head movement — inertial load from grazing and head shaking
• Combined — simultaneous gravity and lateral inertial load

Firmware Plan

The ESP32 will run a polling loop that wakes from deep sleep at a set interval, reads temperature and IMU data, compares against a rolling per-animal baseline, and either logs the reading or triggers an alert if thresholds are exceeded. Between readings the device returns to deep sleep to minimize current draw and extend battery life between solar recharge cycles.

Next Steps

• Finalize SolidWorks enclosure geometry and run solar bracket FEA
• Place parts orders — ESP32-S3 SuperMini (Amazon), DS18B20 5-pack and MPU-6050 5-pack (AliExpress), LiPo batteries and TP4056 boards (AliExpress)
• Source Pi Zero 2W from Adafruit or PiShop for gateway
• 3D print prototype enclosure in PETG and fit-check all components
• Write and test ESP32 firmware for sensor polling and deep sleep cycling
• Characterize 30×25mm solar cell output under typical outdoor conditions vs 400mAh battery draw
• Develop BLE communication protocol between tag and gateway ESP32

This page will be updated with CAD renders, FEA results, firmware, and field testing data as the project develops.