Relay Module (3V, 1 Channel)

A low-voltage 3V single-channel relay module with opto-isolation. Switches AC or DC loads safely from a 3.3V microcontroller (ESP32) without needing a level shifter. This is the part used in Workshop 02 - Light up the Tree.

Features

• 3.3V operation (compatible with ESP32)
• Single channel
• Normally Open (NO) and Normally Closed (NC) contacts
• Max load: 10A / 250VAC or 10A / 30VDC
• Opto-isolated input for safety
• LED indicator for relay status
• Active LOW trigger
• No external driver circuit needed

High-voltage warning

A relay can switch mains-voltage loads (110V / 220V), which can cause serious injury or death if mishandled. Read the safety section in Workshop 02 - Light up the Tree before wiring anything to mains. If unsure, stick to low-voltage LED loads.

Resources

• ESP32 IO - Relay tutorial
• Random Nerd - ESP32 relay module web server

Where to buy

• AliExpress
• Amazon US
• Amazon Germany

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Adapted from the CardanoThings project, originally produced under Project Catalyst Fund 11. Source: github.com/CardanoThings.