5V 4-Channel Relay Shield Module for Arduino UNO R3

Four switched circuits from one small board. This 5V relay shield plugs onto an Arduino UNO R3 footprint, so a sketch can switch lights, pumps or workshop gear instead of you reaching for four separate switches. Each channel has its own screw terminals and red indicator. Built for hobbyists and small automation builds.

Four relays, one shield, fewer loose wires

✅ Switches four circuits independently Four relays on one board, each with its own NO, NC and COM screw terminal pair.

✅ Shows which channel is live A red LED sits beside each relay and lights when that channel is driven high.

✅ Fits the UNO shield footprint Standard shield shape and headers mean it plugs straight in, with no patch cables to trace.

✅ Stack another board on top The headers let you keep stacking expansion boards for the next stage of the build.

✅ Works with either logic level A high signal from 5V or 3.3V boards closes the relay, so mixed setups work.

Wiring is the part that eats an evening, so every connection lands on a screw terminal: strip the wire, clamp it, and that channel is done. The three contacts per relay cover the usual two cases, switching a load on when the sketch drives the pin high, or leaving it on until it does. Number the channels before you mount the board; the relay numbering is printed on it.

The coil side has its own 5V DC barrel jack, which gives you the option of feeding the relays from a separate supply instead of pulling everything through the host board. That helps when four relays switch at the same moment and the rest of the build is already drawing current.

One check before ordering: this is a shield, so it expects a board built to the UNO R3 outline, and the same footprint is used by many ARM, PIC, AVR and DSP boards. The three M3 holes let you fix the stack to a panel or a printed bracket rather than leaving it loose on the bench.

Keep the green terminal blocks clear of a metal shell or housing when the stack is powered. With a UNO underneath, the USB connector stands proud of the board, so a tight case can touch the terminals and short them.

Technical details

• Supply voltage: 5V DC
• Channels: 4 independent relays
• Relay type: HJR-4102-L-5V, 5V DC coil
• Contacts per channel: NO, NC and COM screw terminals
• Indicators: one red LED per channel
• Control signal: high-level drive, 5V or 3.3V logic
• Mounting: 3 x M3 screw holes
• Board format: Arduino UNO R3 shield outline, stackable
• Power input: 5V DC barrel jack

Pick the relay shield for the UNO project on your bench, then check your logic level before wiring.

See more: explore more smart home control boards