#4 - Portable FM Radio

Project Overview

Description: A portable, battery powered FM radio with a display and buttons. It’s controlled by the ESP32-S3-WROOM1 microcontroller. The Portable FM Radio uses a Skyworks AM/FM/SW/LW Radio Receiver (Si4735 IC) to receive FM radio frequencies and output analog audio to an amplifier for the speaker and headphone jack.

Features: 

1. LCD screen to display the radio station, song name, volume, and signal strength.

2. Buttons control volume up/down, channel tuning (±0.2 MHz), and a cycle between preset stations

3. Automatic audio switching between headphone jack or speaker

4. Automatic load switching with USB-C and a rechargeable LiPo battery with status LEDs

5. 3D-printed case to house the PCB and all the electronics. Makes speaker sound more full

Categories Fulfilled:

• Compute - ESP32-S3-WROOM1

• Power - USB-C 5V and LiPo Battery, 3.3V LDO

• Sensing - Voltage sensor to monitor battery voltages (under 3.6V), Button presses, Radio FM sensing

• Actuation - LCD Display and Speaker/audio system

Reflections

• Goal and Intended Function?

  • The goal was to create a PCB that could receive FM Radio channels, output their audio to a speaker or headphones, and display relevant information on a screen.

• Goal Met?

  • Surprisingly, yes!

• Issues and Areas for Improvements

  • P Channel MOSFETs

  • Wire up the Missing CLK on the PCB

  • Cleaner PCB layout (smaller, cleaner wire routing, fewer vias)

• Learn Outcomes?

  • Lots of Soldering Practice

  • The Entire PCB Design and Bringup Process

  • Coding a Microcontroller to Interact with our Hardware

  • Coming up with Solutions Quickly for Errors in the Circuit

  • Tolerancing a CAD Model for Little Electronic Components