Project Hub /IoT & Connected Devices/Smart Home & Building Automation/IoT Based Smart Reminder System

Intermediate

ESP32

₹1,500 – ₹5,000

3 – 6 Hours

Partial Kit

IoT Based Smart Reminder System

An IoT-based smart reminder system using an ESP32 that provides both visual notifications via an e-paper display and voice announcements through a speaker.

Originally published on CircuitDigest

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

ESP32 WiFi+Bluetooth CP2102 Development Board Rs. 520.00
10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: LCD (generic / unspecified)
Speaker / Audio Amplifier
Perfboard / Veroboard / Stripboard
Capacitors

Browse all components

How It Works

The IoT Based Smart Reminder System functions by combining Wi-Fi connectivity, low-power visual output, and audio playback managed by an ESP32 Development Board. The ESP32 connects to a local wireless network using its integrated Wi-Fi and WebServer libraries, allowing it to fetch time-synchronized reminder data and trigger events. When a reminder is activated, the system updates a Waveshare 1.54-inch e-paper display. Because e-paper technology is bistable, it retains the visual message without drawing continuous power, updating only when the pixel states change. Simultaneously, the system generates voice announcements using software libraries like AudioGeneratorMP3 and AudioOutputI2S. The digital audio stream is processed and driven by a circuit featuring an ADA4841-2 Operational Amplifier configured for signal conditioning, alongside a PAM8403 Audio Amplifier connected to a speaker. Passive components, including 1uF and 1nF capacitors and 100k and 47k Ohm resistors, are integrated onto a dot board to stabilize supply voltages, filter noise in the analog audio paths, and set proper bias levels for the operational amplifier. This combination of connected scheduling, persistent visual e-paper output, and amplified audio notifications ensures that reminders are both seen and heard clearly.

Why Build This

Assisting elderly people, busy professionals, and students with daily time management and critical reminders without relying on smartphones or constant power.

Gaining hands-on engineering experience in integrating IoT web servers with local audio synthesis and low-power bistable display technologies.

Applying analog signal conditioning principles using operational amplifiers and digital-to-audio interfaces within a custom-wired dot board prototype.

Real-World Application

Assisting elderly people, busy professionals, and students with daily time management and critical reminders without relying on smartphones or constant power.

Skills You'll Learn

IoT web server deployment

e-paper display interfacing

digital audio generation

operational amplifier signal conditioning

audio amplifier integration

passive filter design

Safety Precautions

No specific precautions noted for this build — always follow general electronics safety practices.

Technology Tags

ESP32

IOT

WI-FI

E-PAPER DISPLAY

AUDIO AMPLIFIER

PAM8403

ADA4841-2

TEXT-TO-SPEECH

LITTLEFS

WEB SERVER

Frequently Asked Questions

Why use an e-paper display instead of a standard LCD or OLED?

An e-paper display draws power only when changing its image, making it ideal for persistent reminders that need to stay visible without constantly consuming battery or power.

What is the role of the ADA4841-2 operational amplifier in this circuit?

The operational amplifier is used for analog signal conditioning, helping to process and stabilize the audio signals before they reach the PAM8403 amplifier and speaker.

Can this system operate without an active internet connection?

The system relies on Wi-Fi and web server libraries to receive IoT-based updates, so an active network connection is required to fetch new reminders.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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