Web3_mpy - Micropython IOT

Web3_mpy

web3_mpy is a minified version of web3.py adapted for use in MicroPython, enabling interaction with the Ethereum blockchain on resource-constrained IoT devices.

Features

• Compatible with MicroPython.
• Communication with Ethereum nodes via HTTPProvider.
• Support for raw transactions.
• Interaction with smart contracts using ABI.
• Optimized for devices with limited memory.
• Ability to sign transactions and send them to the blockchain.
• Creation of wallets with public and private keys.
• Access to smart contracts for sending tokens, reading methods, and performing advanced interactions.
• Compatibility with any Ethereum Virtual Machine (EVM)-based node.

Testing and Limitations

This project has been tested on different devices:

• ESP32: Successfully used.
• ESP8266: memory is the main limitation. It cannot process signatures due to low internal RAM.
• Raspberry Pi: Successfully used, but required modifications to some specific libraries due to differences in the execution environment.

It has also interacted with multiple EVM-compatible blockchain networks, including:

• Ethereum (Mainnet and Sepolia)
• Binance Smart Chain (BSC) and BSC Testnet
• Polygon
• Arbitrum

The main security firewall is based on MicroPython.

Installation

Since MicroPython does not natively support pip, you must manually copy the web3_mpy files to your IoT device.

1. Clone or download this repository.
2. Import the modules into your MicroPython code.

Usage

Below is an example of how to connect an IoT device to the Ethereum blockchain and retrieve the BTC/USD price from a Chainlink smart contract.

# main/get_price_btc_mainnet_ethereum.py

import json, time, sys, gc

def clear_memory():
    gc.collect()

# Agrega el directorio actual (donde se encuentran main.py, network_iot.py y web3_mpy) a sys.path
if "/my_modules" not in sys.path:
    sys.path.insert(0, "/main")

from web3_mpy.web3 import Web3, HTTPProvider
from web3_mpy.tx import construct_raw_tx
from web3_mpy.contract import Contract
from network_iot import Network


# Configuración de red Wi-Fi
ssid = ""
password = ""
static_ip_config = None
net = Network(ssid, password, static_ip_config)
if not net.conectar():
    print("Error al conectar la red. Saliendo...")


# Configuración del proveedor (por ejemplo, usando Infura y la red Sepolia)
infura_url = "https://mainnet.infura.io/v3/Token_infura"
provider = HTTPProvider(infura_url)
w3 = Web3(provider)


# Carga del ABI del contrato token (archivo abi.json)
with open('main/abi_oracle_Btc_Usd.json', 'r') as abi_file:
    contract_abi = json.load(abi_file)

# Dirección del contrato del token y la dirección destino
CONTRACT_ADDRESS = "0xF4030086522a5bEEa4988F8cA5B36dbC97BeE88c"  # Reemplaza con la dirección real del contrato

# Crea una instancia del contrato utilizando la funcionalidad de contratos de la librería
contract = w3.eth.contract(address=CONTRACT_ADDRESS, abi=contract_abi)

# Ejemplo de uso con variables de contrato:
#
# Supongamos que has obtenido los siguientes valores con .call():
# - description: una cadena dinámica codificada.
# - decimals: un entero (codificado en 32 bytes).
# - latestAnswer: un entero.
# - latestRoundData: una concatenación de 5 valores (por ejemplo, [roundId, answer, startedAt, updatedAt, answeredInRound]).

# Valores obtenidos (ejemplo):
clear_memory()
description = contract.functions.description().call()
print("Resultado decodificado:", description)

latest_round_data = contract.functions.latestRoundData().call()
print("Resultado decodificado:", latest_round_data)

decimals = contract.functions.decimals().call()
print("Resultado decodificado:", decimals)

latestAnswer = contract.functions.latestAnswer().call()
print("Resultado decodificado:", latestAnswer)
precio_normalizado = latestAnswer / (10 ** decimals)
print("Resultado normalizado:", precio_normalizado)

Dependencies

• MicroPython with support for ujson and urequests.
• An Ethereum RPC provider such as Infura or Alchemy.
• An IoT device with WiFi connectivity.

Contributions

Contributions are welcome. If you want to improve the library, fork the repository and submit a Pull Request with your changes.

License

This project is licensed under the MIT License.

Donations

If you like this project and want to support it, you can donate:

• Buy me a coffee ☕

  • Ethereum Wallet: 0x06701723194aF926f01D8480fA559642c425f077

• Get to work and improve the library 💪

  • Ethereum Wallet: 0x1461039624C4461C1b2a9805DCa9bdf97AD81538