Calving in cattle is divided into two main stages: dilation and expulsion, during which timely assistance can reduce reproductive losses. This study presents a smart ear-mounted device as a proof-of-concept heart-rate monitoring platform for calving-stage assessment in dairy cows. The prototype preserves the form factor of a conventional ear tag and integrates a MAX30105 optical sensor, an Arduino Nano microcontroller, local micro-SD storage, and an autonomous power supply. Field tests were conducted in Holstein cows at Rancho El Pinar, Trancoso, Zacatecas, Mexico. Heart rate was recorded every 10 min and grouped according to physiological stages around calving. The results showed distinctive heart rate patterns, with higher values during dilation and lower values after delivery, supporting the use of ear-mounted heart rate monitoring as a non-invasive descriptive marker of stage-related physiological variation around labor. An average temperature profile from 70 h before to 50 h after calving was also incorporated as complementary descriptive evidence of peripartum physiological variation. Because heart rate is a non-specific physiological variable affected by stress, movement, ambient temperature, feeding, health status, and sensor contact, the present study does not propose HR as a stand-alone or definitive predictor of calving or dystocia. Instead, the device is presented as a proof-of-concept platform for future multi-indicator monitoring and validation studies. The proposed system is presented as a proof-of-concept invention that combines a practical wearable format with physiological monitoring and a conceptual decision-support logic that remains to be validated and integrated with additional indicators before any field implementation.

This work consists of the design and implementation of a TENS electrostimulator (Transcutaneous Electrical Nerve Stimulation), which generates its signal with an oscillator created from a NE555 Timer, in which, its shape and signal amplitude can be varied from potentiometers, in order to also modify the frequency at which it will work and which is connected to a power stage with a tip31C transistor, in addition to having its own power source, which connects directly to the alternating current at home, since it has its respective transformers and diode bridge to rectify the signal, also integrating voltage regulators to avoid noise and distortions of the signal, and thus be able to generate electrical impulses that can be used in the human body for therapeutic use. Obtaining an electrostimulator that generates an electrical impulse signal for the use of electrotherapy with a preliminary established frequency of 100Hz.

Phase-angle AC control is a low-cost technique for regulating power in resistive loads, but its performance depends on accurate trigger timing. This study quantitatively compares an ESP32-based phase-angle controller implemented in MicroPython and in native C using ESP-IDF. Firing delay was measured over 1000 consecutive cycles at firing angles from 10° to 150° under a 60 Hz supply, and the timing error was converted into equivalent angular deviation. The native C implementation reduced the mean timing error from 218.2–234.7 μs in MicroPython to −10.3–6.1 μs after calibration, corresponding to an average improvement of approximately 225 μs or 4.86° across the tested angles. In the current dataset, the measured standard deviation remained angle-dependent and numerically similar in both environments, ranging from 2.5 to 10.1 μs. Oscilloscope measurements confirmed the expected phase-angle operation and the practical timing displacement between firmware strategies. The results show that the principal advantage of the native implementation is improved absolute synchronization accuracy, whereas the residual short-term jitter remains dominated by the shared detection and triggering chain.