# Node-RED Relay Control

Day 87 of the 100 Days 100 IoT Projects collection. Board: Pi Pico.

Switch relays from Node-RED flows over MQTT on the Pico 2W. Industrial-style control logic, drag-and-drop.

## How it works

Relay logic lives in Node-RED flows: dashboard switches and automation rules publish MQTT commands, and the Pico 2W executes them on its relays. Change the behavior by rewiring nodes in the browser — no firmware reflash to alter the logic.

## What you'll learn

- Visual control logic
- MQTT command topics
- Logic without reflashing
- SCADA-style supervision

Full project (code, wiring diagram, Wokwi simulation): https://github.com/kritishmohapatra/100_Days_100_IoT_Projects/tree/main/Relay_Control_via_Node_RED_&_MQTT

Summary by SkillShop. Code and diagrams belong to the original repo.