After seeing Oliver Ettlin's 39C3 presentation Excuse me, what precise time is It?, I wanted to replicate the PTP (Precision Time Protocol) clock he used live to demonstrate PTP clock sync:



I pinged him on LinkedIn inquiring about the build (I wasn't the only one!), and shortly thereafter, he published Gemini2350/ptp-wallclock, a repository with rough instructions for the build, and his C++ application to display PTP time (if available on the network) on a set of two LED matrix displays, using a Raspberry Pi.

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A step-by-step build guide for a PTP (Precision Time Protocol) wall clock using a Raspberry Pi 4, two 64x32 RGB LED matrix panels, and an Adafruit RGB Matrix HAT. Covers required hardware (~$120-150), soldering and wiring setup, OS configuration (CPU isolation, audio blacklisting), compiling the rpi-rgb-led-matrix library and ptp-wallclock C++ app, PTP debugging tips (tcpdump, two-step mode), and a 3D-printed bracket design available on Printables. Requires a PTP grandmaster on the local network broadcasting to the standard multicast address.

A PTP Wall Clock is impractical and a little too precise