Blockchain-Logged Access Control Kit with ESP32 + Relay
Build Blockchain-Verified Access Logs with the ESP32 RFID & Relay 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.
Every RFID badge swipe triggers a cryptographic hash, chained to the previous event in EEPROM, forming an immutable record. The ESP32 verifies the entire chain at startup, instantly flagging any tampering. This advanced kit is built for security engineers, IoT researchers, and final‑year engineering students prototyping verifiable access control systems.
What You'll Build
You will assemble a complete physical access system: an MFRC522 reader scans RFID cards, the ESP32 checks authorization, and a relay activates the solenoid lock. But the core innovation is the blockchain‑style log. Each access event is hashed with the previous event’s hash, creating a chain that cannot be altered without detection. A real‑time clock stamps every entry, the OLED displays chain integrity, and a MicroSD stores JSON backups.
What You'll Learn
- Implement SHA‑256 hashing and chaining on an EEPROM to create a tamper‑evident ledger
- Interface an MFRC522 RFID module, 5V solenoid lock, and relay with ESP32
- Use a DS3231 RTC for precise timestamps and a MicroSD module for extended log storage
- Verify blockchain integrity algorithmically on a microcontroller, detecting any inserted or deleted entries
Kit Contents
| Component | Quantity |
|---|---|
| ESP32 Dev Board | 1 |
| MFRC522 RFID | 1 |
| RFID Cards | 10 |
| 5V Solenoid Lock | 1 |
| 5V Relay Module | 1 |
| DS3231 RTC | 1 |
| MicroSD Module | 1 |
| 0.96in OLED | 1 |
| LM2596 Buck Converter | 1 |
| 100nF Caps | 10 |
| 10kΩ Resistors | 5 |
| PCB Prototype Board | 2 |
| Enclosure Box | 1 |
| 12V Adapter | 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
Designed for advanced makers, B.Tech ECE/EEE final‑year students building capstone projects, Smart India Hackathon participants tackling security track challenges, and embedded systems professionals prototyping blockchain‑based IoT solutions. Equally suited for researchers at IITs, NITs, VIT, and BITS Pilani exploring verifiable audit trails.
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 to access your AI companion trained on this kit; it explains every hashing and chain‑verification step. Our WhatsApp support team can also walk you through the blockchain integrity algorithm.
Do I need prior blockchain experience?
No—the kit teaches blockchain principles from scratch on a microcontroller. However, you must be comfortable with ESP32 C/C++ programming and basic circuit wiring.
Can I adapt this to control a gate motor instead of the solenoid lock?
Yes, the 5V relay switches up to 10A; just use a suitable external power supply for your gate motor and ensure the motor’s current rating matches the relay’s capacity.
How long does a complete assembly and software verification take?
Plan for 15–20 hours of careful soldering, wiring, and testing. Set aside extra time if you want to customise the chain verification logic or extend the JSON logging format.
RFID access events hashed and chained in EEPROM forming an immutable tamper-evident access log. ESP32 verifies chain.
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