Phase Vocoder Time Stretcher Variant 20 Kit with Arduino Due + LED
Achieve Perfect Slow-Down Practice with the Arduino Due Phase Vocoder Time Stretcher Kit
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
Musicians know the frustration of trying to learn a fast passage. Slowing down a recording on a phone or app often lowers the pitch, making it sound unnatural and unmusical. The Phase Vocoder Time Stretcher Variant 20 Kit uses the Arduino Due to perform overlap-add Short-Time Fourier Transform (STFT) in real time, stretching audio to exactly half speed while preserving the original pitch. This hardware device lets you plug in a microphone, speak or play an instrument, and hear your sound played back at half tempo, perfectly in tune. Ideal for dissecting complex ragas, solos, or any fast piece.
What You'll Build
A standalone, self-contained time-stretching device with a microphone input, OLED display, and speaker output. When you speak or play, the Arduino Due's 32-bit ARM processor captures audio via the MAX9814 mic, computes the STFT, and reconstructs the signal at half speed without pitch shift. The MCP4725 DAC and PAM8403 amplifier deliver clear audio through the 3W speaker, while the OLED shows the stretching status. The system fits neatly in the supplied enclosure, ready for your practice corner.
What You'll Learn
- Implementing the Overlap-Add method for a real-time phase vocoder on a microcontroller
- Configuring the Arduino Due's ADCs and DMA for high-speed audio capture
- Interfacing I2C DAC (MCP4725) and amplifier for high-quality output
- Optimising fixed-point DSP algorithms for the ARM Cortex-M3 to achieve 50% time stretch with minimal latency
Kit Contents
| Component | Quantity |
|---|---|
| Arduino Due | 1 |
| MAX9814 Mic | 1 |
| MCP4725 DAC | 1 |
| PAM8403 Amp | 1 |
| 3W 8Ω Speaker | 1 |
| 0.96in OLED | 1 |
| 100nF Caps | 15 |
| PCB Prototype Board | 2 |
| Enclosure Box | 1 |
| 9V 1A PSU | 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 engineers, musicians, and makers who want to explore real-time audio DSP. It suits B.Tech ECE and EEE students diving into signal processing for their final-year projects, as well as hobbyists attending hackathons like Smart India Hackathon where embedded audio solutions stand out. IIT, NIT, VIT, and BITS Pilani students will find the theoretical concepts of STFT and overlap-add directly applicable to their coursework and research.
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?
The AI companion, pre-loaded with this project's exact steps, is your first support. If you need human help, WhatsApp a video of your issue and our engineers typically respond within a few hours.
Can I change the stretch factor from 0.5 to something else?
The firmware is pre-loaded for exactly half-speed operation. Advanced users can modify the Arduino sketch to adjust the overlap factor and achieve other ratios; full source code and documentation are included.
Do I need an oscilloscope to verify the output?
No, the onboard OLED displays live spectral information and stretch status, allowing you to confirm correct operation. For deeper analysis, you can connect the DAC output to a PC sound card.
What if I don't have soldering experience?
The kit includes a soldering iron and solder wire, and the AI companion guides you through every joint. With patience, a beginner can complete the PCB assembly, though familiarity with basic soldering is beneficial.
Arduino Due implements overlap-add STFT to stretch audio to half speed without pitch change for slow practice.
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.
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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