Overview
This project is a portable, battery-powered device that generates signals at adjustable frequency, amplitude, and waveform (sine, square, triangle, sawtooth). Its core is an ESP32, controlled via a custom Android app we built from scratch over BLE (Bluetooth Low Energy). From the app, you can select a single signal or a sequence of up to 20 signals, each with its own duration and type. We designed the antenna ourselves, carried out theoretical calculations, and validated them with oscilloscope and LCR-meter measurements.
Goals and Objectives
Our customer wanted a portable system that could generate signals at different frequencies and waveforms from a single device, easily configurable from a phone. Our goal was to correctly engineer both the antenna and signal-generation side through proper calculations, and make the device easy to control through a user-friendly mobile app.
Development Process
We first carried out the theoretical calculations for the antenna design and signal-generation circuit, then validated them with oscilloscope and LCR-meter measurements. We calculated the device's battery system — which needed a dual ±7.4V supply — along with the BMS (battery management system) design and estimated runtime. In parallel, we built an Android app from scratch; it sends JSON signal commands to the device over BLE, letting the user select frequency (1 Hz–100 kHz), waveform type, duration, and single/multi-signal mode.
