. picture, the positive leg (long leg) of the LED is connected to pin number 21 of the GPIO, and the negative (short leg) is connected to the resistor, which is then connected to the ground (GND) pin of the GPIO.
Once the connections are set up the ribbon cable can be used to connect to the GPIO connector on the Raspberry Pi simply.
A Complete Guide to Understanding This Blockchain Concept
Connections for components on the breadboard Once the connections are set up correctly, and the Raspberry Pi has been updated with the appropriate libraries and Geth, the next step is to develop a simple, smart contract that expects a value.
If the value provided to it is not what it expects it does not trigger an event; otherwise if the value passed matches the correct value, the event triggers which can be read by the client JavaScript program running via Node.js.
Of course, the Solidity contract can be very complicated and can also deal with the Ether sent to it, and if the amount of Ether is equal to the required amount, then the event can trigger.
However, in this example, the aim is to demonstrate the usage of smart contracts to trigger events that can then be read by JavaScript program running on Node.js, which then, in turn, can trigger actions on IoT devices using various libraries.
The smart contract source code is shown as follows: Solidity code for simple IOT The online Solidity compiler (Remix IDE) can be used to run and test this contract.
The Application Binary Interface (ABI) required for interacting with the contract is also available in the Details section. screenshot:
Why This Matters for Blockchain Technology
Understanding Circuit is not just an academic exercise — it has real-world implications for how blockchain systems are designed, deployed, and secured. Whether you are a developer building decentralized applications, a business leader evaluating blockchain adoption, or a curious learner exploring the technology, this knowledge provides a critical foundation.
Key Points to Remember
- Circuit. picture, the positive leg (long leg) of the LED is connected to pin number 21 of the GPIO, and the negative (short leg) is connected to the resistor, which is then connected to the ground (GND) pin of the GPIO.
- Once the connections are set up the ribbon cable can be used to connect to the GPIO connector on the Raspberry Pi simply.
- Connections for components on the breadboard Once the connections are set up correctly, and the Raspberry Pi has been updated with the appropriate libraries and Geth, the next step is to develop a simple, smart contract that expects a value.
- If the value provided to it is not what it expects it does not trigger an event; otherwise if the value passed matches the correct value, the event triggers which can be read by the client JavaScript program running via Node.js.
Conclusion
Circuit represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.