Covert Audio Logger Variant 25 Kit with Arduino Uno + LED
Build a Voice‑Activated Audio Logger with Precise Timestamps — Arduino Uno + RTC
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
Imagine a device that sits silently in a room, listening for the faintest murmur, and only when a sound breaks the silence does it begin recording — stamping each file with the exact date, hour, minute, and second from a battery-backed clock. That’s the covert audio logger you’ll build with this kit. Designed for security monitoring, evidence gathering, or simply capturing critical moments in an unattended space, it records .WAV audio to a microSD card at the first sign of noise. Once the sound drops below your set threshold, the recording stops, keeping files small and easy to review.
What You'll Build
You’ll assemble a compact, battery-powered audio recorder around an Arduino Uno. A MAX4466 microphone amplifier picks up ambient sound and the firmware constantly samples the noise level. When it crosses the threshold you program, the DS3231 RTC supplies a timestamp, the microSD module creates a new file named with that stamp, and the OLED displays the system status — armed, recording, or idle. The whole circuit fits on a prototyping board and runs off a rechargeable LiPo cell, making it fully portable and discreet.
What You'll Learn
- Sampling audio with the MAX4466 and setting a software-triggered recording threshold.
- Interfacing a DS3231 real‑time clock over I2C to timestamp every recording event.
- Managing file creation and writing with an SD card module using the SdFat library.
- Designing a low‑power, battery‑operated Arduino system with LiPo charging circuitry.
Kit Contents
| Component | Quantity |
|---|---|
| Arduino Uno R3 | 1 |
| MAX4466 Mic Amp | 1 |
| DS3231 RTC | 1 |
| MicroSD Module | 1 |
| 0.96in OLED | 1 |
| 10kΩ Resistors | 5 |
| 100nF Caps | 10 |
| PCB Prototype Board | 2 |
| 3.7V LiPo 1000mAh | 1 |
| TP4056 Module | 1 |
| Soldering Iron | 1 |
| Solder Wire | 1 |
Why Buy This Kit Instead of Sourcing Parts Separately
| Factor | Sourcing Separately | Compoden Kit |
|---|---|---|
| Compatibility checks | You verify every part | Pre-tested as a system |
| Build support | Forums and scattered tutorials | AI companion trained on this exact project |
| Time to first working build | Days of debugging | Hours, with step-by-step guidance |
| Shipping coordination | Multiple sellers, multiple delays | One shipment from Bengaluru in 3-5 days |
Who This Kit Is For
This kit is built for B.Tech ECE/EEE final‑year students working on security and surveillance projects, Smart India Hackathon participants designing IoT monitoring solutions, and researchers who need reliable timestamped audio evidence. If you’re at an NIT, IIT, VIT, or BITS and need a ready‑to‑assemble recording system that demonstrates real‑time embedded processing, power management, and file I/O, you’ll find everything here.
Built and Backed by Compoden
Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.
What if I get stuck during the build?
Scan the QR code in your box to open the AI companion, trained on this specific project. It can guide you through wiring, code upload, and debugging. If you need a human, our WhatsApp support team is also ready to help.
How sensitive is the sound activation, and can I adjust it?
The threshold is set in the Arduino sketch — you can tune a numerical value that corresponds to the ADC reading from the MAX4466. The AI companion will show you how to change it so the recorder triggers on a whisper or only on louder noises.
Can I power the device for overnight surveillance without a wall outlet?
Yes, the included 1000mAh LiPo and TP4056 charging module give you several hours of standby listening. For all‑night runs, you can connect a USB power bank to the Arduino’s USB port while still using the battery as a buffer.
Will the timestamps stay accurate if power is lost?
The DS3231 RTC has its own coin cell backup, so it keeps perfect time even when the main battery dies. Dates and times on your recordings remain correct across power cycles.
MAX4466 records ambient audio to SD card with RTC timestamps. Activates only on sound above threshold.
What's in this kit
Choose your assembly option:
- Soldering Kit — 25W soldering iron, 60/40 solder wire, flux, and small perfboard for permanent assembly.
- Breadboard Combo — 800-point full-size breadboard with 65-piece jumper wire pack for solderless prototyping.
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items