$IOTX Below you will find a possible concept for an IoT device that implements a smart locking mechanism (e.g., on a door, box, or cabinet) using an RFID tag and the IoTeX blockchain. The concept should not be understood as a finished blueprint, but rather as a guideline for the technical and organizational steps you should consider in implementation.
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1. Basic idea and system overview
Goal
An IoT device (‘Smart Lock’) reads an RFID tag, checks via the IoTeX blockchain or smart contracts if the RFID tag (or its owner) is authorized to open the lock, and then controls the locking mechanism.
Components
1. RFID module: To capture the UID (Unique ID) of the RFID chip.
2. Microcontroller/SoC: E.g., an ESP32, Raspberry Pi Pico W, STM32 with WLAN/Ethernet or comparable chip – network capability and sufficient resources are important.
3. Network module: WLAN or Ethernet to connect to the Internet or the IoTeX blockchain.
4. Blockchain interaction layer: Software library or web API to perform transactions or queries to IoTeX.
5. Smart contract on IoTeX: Here, it is stored which RFID UID is authorized to open the lock.
6. Actuator: Motor, servo, or electromagnet that opens and closes the physical lock.
7. Power supply: Possibly via power supply (5V or 12V) or battery (including possibly solar panel or battery management), depending on the location.
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2. Functional process
1. RFID scan
• A user holds their RFID chip (e.g., in the form of a key card, transponder, or NFC card) to the reader.
• The RFID module reads the unique ID (UID) of the tag.
2. Security check / Authentication via IoTeX
• The microcontroller sends this RFID UID as a request to a smart contract on IoTeX, either directly through a lightweight blockchain client or through a proxy server/backend that handles the blockchain query.
• The smart contract checks whether this UID is currently registered in a list of approved access permissions (e.g., in a mapping approvedUIDs => true/false).
• If the UID is allowed in the smart contract, the microcontroller receives the signal ‘Opening allowed’.
3. Lock control
• Upon successful authentication, the microcontroller controls the electric actuator (servo, actuator motor, or electromagnet) to unlock the lock.
• Optionally, feedback (LED signal or acoustic signal) can be provided to the user.
4. Logging and event handling
• With each opening, the IoT device can trigger or log an event on the blockchain (e.g., ‘DoorUnlocked(UID, Timestamp)’) to make accesses transparent.
• If the UID is not valid, an alarm or a rejected request can be logged (e.g., ‘AttemptedAccess(UID, Timestamp)’).
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3. IoTeX-specific implementation
On the IoTeX blockchain, you can consider the following:
1. Smart Contract
• Create a simple smart contract, e.g., in Solidity or an IoTeX-compatible language (IoTeX runs EVM-like).
• An example of a mapping:
mapping(bytes32 => bool) public approvedUIDs;
function addUID(bytes32 _uid) public {
// Here, possibly check roles, owner rights, etc.
approvedUIDs[_uid] = true;
}
function removeUID(bytes32 _uid) public {
// Only certain users (owners) are allowed to remove
approvedUIDs[_uid] = false;
}
function isApproved(bytes32 _uid) external view returns (bool) {
return approvedUIDs[_uid];
}
• With the RFID reader, you usually get a UID as a hexadecimal string or binary value. You can convert it into a bytes32 value and store it in the smart contract.
2. Communication with IoTeX
• A small firmware module or library that communicates with an IoTeX node via HTTP/JSON RPC or WebSocket.
• Alternatively, a dedicated web server/backend in Node.js or Python can run, which handles the actual blockchain query and offers a simpler protocol (e.g., REST API) to the IoT device.
3. Event logging
• You can define an event in the smart contract, e.g.:
event DoorUnlocked(bytes32 indexed uid, uint256 timestamp);
event AccessDenied(bytes32 indexed uid, uint256 timestamp);
• If the IoT device has a success or failure, it sends a transaction that logs the corresponding event on the blockchain.
• This step is optional, as any on-chain interaction incurs fees (gas). For very frequent door openings, off-chain logging with periodic hash verifications on the blockchain may be advisable.
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4. Hardware requirements
1. RFID reader
• Depending on the RFID type: 125 kHz (e.g., EM4100) or 13.56 MHz (NFC, MIFARE).
• Pay attention to the appropriate protocol (I2C, SPI, UART). Frequently used are RC522 (MIFARE) or PN532.
2. Microcontroller
• ESP32 (popular for IoT projects): Has WLAN, Bluetooth, enough GPIOs, and sufficient power.
• STM32 + separate WLAN/Ethernet module.
• Raspberry Pi Pico W: Similar to ESP32, also very inexpensive.
3. Actuator
• Depending on the desired pulling force: a small servo, an electromagnet, or a DC motor with gearbox (e.g., for door locks).
• Relay module or MOSFET/transistor for power control at higher currents.
4. Power supply
• Should be able to provide the actuator's short-term power peaks (e.g., 5V / 2A).
5. Security
• At the hardware level, possibly TPM/enclave or a secure storage module (secure element), so that the keys for blockchain interactions are securely stored.
• Securing the radio link (WLAN with WPA2/WPA3, TLS in communication).
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5. Software architecture
1. Device firmware (microcontroller)
• Reads the RFID UID via SPI/I2C/UART.
• Send this UID either directly via HTTP/HTTPS POST to an IoTeX endpoint or to a middleware server.
• Waiting for response (Approved / Denied).
• Controls the actuator accordingly.
2. Blockchain interaction layer
• Library or REST endpoint running on the microcontroller (e.g., a lightweight library for IoTeX), or
• External server (e.g., Node.js) that communicates via JSON-RPC with IoTeX nodes and returns a simple ‘true/false’ to the microcontroller.
3. Management of RFID tags
• Web interface where you can add or remove new RFID tags (UIDs). This tool calls smart contract functions.
• An access control list (ACL) can be maintained on the contract (e.g., only the owner can add new UIDs).
4. Logging/analysis
• Option: The device sends a transaction to the smart contract upon successful opening that triggers an event (e.g., DoorUnlocked(UID, block.timestamp)).
• For mass events, you can log off-chain and periodically save the hash of the log file on-chain.
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6. Security and privacy
1. RFID card clonability
• Many simple RFID tags are relatively easy to copy. Therefore, you may want to use MIFARE DESFire or similar security standards (encrypted RFID protocols).
• For particularly high security, the RFID tag itself can support cryptographic methods (challenge-response).
2. Network security
• Minimal attack surface through firewalls, secure firmware, and regular software updates.
• Communication with the IoTeX network via HTTPS/TLS with certificate verification.
3. Blockchain transaction fees
• Each on-chain step may cost gas. Carefully consider which operations you really want to represent on-chain and whether an off-chain approach with periodic verification is better.
4. Backup/Recovery
• Secure storage of the admin keys of the smart contract so that no one can unauthorized change the access lists and you can regain access in case of emergency.
• Consider failure scenarios: What if there is no Internet or the IoTeX blockchain is temporarily unreachable?
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7. Example project flow
1. Feasibility study:
• Decide whether to use RFID or NFC and how secure it needs to be.
• Choose the microcontroller (e.g., ESP32) as well as the RFID module (e.g., RC522).
2. Develop PoC firmware:
• Write a small program that reads the RFID UID and sends it to a server via HTTP.
• Implement a test smart contract on the IoTeX test network.
• Access the smart contract via JSON-RPC from the server to query isApproved(uid) and return the result.
3. Smart Contract & UI:
• Implement the final smart contract (with approvedUIDs mapping).
• Build a small web interface to add and remove RFID UIDs.
• Test extensively on the IoTeX testnet before going to mainnet.
4. Actuator integration:
• Create or use a ready-made lock module (e.g., an electronic latch or a lock that is controlled via PWM).
• Integrate this into the firmware so that the lock opens on ‘Access granted.’
5. Security and load testing:
• Check the response time, failure scenarios (Internet gone, power gone), and whether RFID cards are sufficiently secure.
• Secure code & smart contract keys.
6. Rollout / installation:
• Mount the device on the desired door/box/cabinet.
• Set up the power supply.
• Test real operation.
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8. Expansion possibilities
• Multiple access profiles: Store multiple permission levels (e.g., time-limited, specific weekdays).
• OTA updates: Implement an over-the-air update function so that firmware updates can be easily deployed.
• Two-factor authentication: In addition to the RFID card, you could require a PIN entry on the device or smartphone.
• Sensor system: For example, a door sensor could report whether the door is actually closed/locked.
• Mobile app: Instead of RFID, a smartphone can also serve as a token that represents a UID or wallet address registered on IoTeX.
• On-site blockchain node: To reduce dependence on the Internet, you could operate a local IoTeX light node if the gateway has stable access.
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Conclusion
With an RFID reader, an internet-capable microcontroller, and a lightweight smart contract on IoTeX, you can realize a fairly secure and transparent access system. The biggest challenge lies in finding the balance between user comfort, security (RFID clonability, network security, smart contract protection), and practicality (costs, power consumption, internet availability). Equally important is clear management of RFID permissions and the admin keys for the smart contract, as manipulation or loss of the keys can otherwise lead to serious security vulnerabilities.
This concept gives you a guide on how to build your own IoT device with RFID support and blockchain backend on IoTeX. The exact implementation steps may vary in detail depending on hardware selection, security requirements, and infrastructure.
