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[ARTICLE · art-10099] src=jeffgeerling.com ↗ pub= topic=open-source verified=true sentiment=· neutral

A PTP Wall Clock is impractical and a little too precise

The article summarizes the author's attempt to replicate Oliver Ettlin's PTP wall clock, which was demonstrated at 39C3 to show precise time synchronization. After contacting Ettlin, the author found that Ettlin had published a repository with build instructions and a C++ application for displaying PTP time on LED matrices using a Raspberry Pi. The author concludes that the project is impractical and overly precise for typical use.

read1 min views18 publishedMar 6, 2026

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.

source & further reading
jeffgeerling.com — original article News about Raspberry Pi 6 and Microcontroller Development Wi-Wi Is Wireless Time Sync at 1 Nanosecond Bambu Lab is abusing the open source social contract
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