SDG #128 Infra-red Remote Protocols and LED Lighting - With new PCBs from JLCPCB

This episode picks up an LED night light project and moves it from breadboard theory to a proper fabricated board, using the build as an excuse to dig into how infra-red remote controls actually encode data.

The infra-red section is the most instructive part. Rather than treating a remote as a black box handled by a library, the signal is captured and examined directly so the carrier frequency, header burst, and the bit encoding scheme become visible. That matters practically: knowing whether a remote uses pulse distance, pulse width, or a bi-phase scheme determines how you write or configure decoding firmware, and understanding the 38kHz carrier explains why demodulating receiver modules behave the way they do near fluorescent lighting or in strong sunlight. Anyone who has fought with an unreliable IR link will recognise why measuring first saves hours of guesswork.

On the hardware side, the discussion covers driving LEDs properly for a lighting application, where constant current control and dimming behaviour matter far more than simply adding a series resistor. Low-brightness dimming performance is where cheap designs fall apart, so the choice of driving method and PWM approach is worth attention if you plan to copy the design.

The project also demonstrates the value of turning a working prototype into a small run of professionally fabricated boards. For a project with mixed through-hole and surface mount parts, a proper PCB removes the wiring gremlins that make prototype debugging ambiguous, and it makes the finished night light something you would actually be willing to install in a room rather than leave on the bench.