mLink Relay Module: 1 vs 2 Channel I2C Comparison
By Official Hobby Components Online Store | Buy Electronic Kits, Components, Boards, Shields, Modules | Published: 2026-10-29
Category: Comparisons
Compare the mLink 1 and 2 Channel I2C Relay Modules. Learn the trade-offs in pin count, cost, and scalability to choose the right parallel relay module for your project.
Quick answer
Choose the mLink 1 Channel I2C Relay Module for simple, low-cost switching of a single load. Choose the 2 Channel version when you need to control two independent circuits from the same I2C bus, balancing pin efficiency with a modest price increase.
Why the number of channels matters
The core difference between these two modules is how many independent relays you can control. The 1-channel module switches one circuit, while the 2-channel module handles two. This directly affects the number of I2C addresses you consume and the physical space on your breadboard or enclosure.
For projects that only need to toggle a single device—like a lamp or a small pump—the 1-channel module is the most economical choice. If your project requires controlling two separate loads, such as a fan and a heater, the 2-channel module saves you from buying and wiring a second 1-channel module.
Cost versus scalability trade-off
The 1-channel module is cheaper per unit, making it the obvious pick for one-off or low-budget builds. However, if you anticipate adding more relays later, buying a 2-channel module now can be more cost-effective than purchasing two 1-channel modules and using two I2C addresses.
For larger systems with three or more relays, neither of these modules is ideal. You would be better served by a dedicated multi-channel relay board that uses a single I2C address to control many relays.
Trade-offs at a glance
- Relay count: 1 channel versus 2 channels
- Cost per relay: The 1-channel module costs less overall, but the 2-channel module gives you a lower cost per relay if you need two.
- I2C address usage: Each 1-channel module uses one I2C address. The 2-channel module also uses one address but controls two relays. If you plan to control many relays, consider modules that support multiple relays per address.
- Physical footprint: The 2-channel module takes up more space than the 1-channel module, but less space than two separate 1-channel modules.
Product facts
- mLink 1 Channel I2C / Parallel Relay Module: The mLink 1 Channel I2C / Parallel Relay Module is a 5V relay module designed for manual or microcontroller control via a serial I2C interface. This allows you to control a single relay using just two I2C pins on your microcontroller, freeing up other digital I/O for sensors or displays.
mLink 1 Channel I2C / Parallel Relay Module - mLink 2 Channel I2C / Parallel Relay Module: The mLink 2 Channel I2C / Parallel Relay Module is a 5V relay module designed for manual or microcontroller control via a serial I2C interface. It controls two independent relays over the same two I2C pins, doubling your switching capacity without increasing the wiring complexity.
mLink 2 Channel I2C / Parallel Relay Module
Which one fits your project?
Best for
- A single load like a lamp, fan, or pump (1-channel)
- Controlling two independent circuits with minimal wiring (2-channel)
Not ideal for
- Projects needing three or more relays (consider a multi-channel relay board)
- Battery-powered or low-voltage projects (these are 5V modules)
