Retro and Open Hardware: Banana Pi, Arduino, and More

posted by Roy Schestowitz on Aug 10, 2025

• Ken Shirriff ☛ A CT scanner reveals surprises inside the 386 processor's ceramic package

  Intel released the 386 processor in 1985, the first 32-bit chip in the x86 line. This chip was packaged in a ceramic square with 132 gold-plated pins protruding from the underside, fitting into a socket on the motherboard. While this package may seem boring, a lot more is going on inside it than you might expect. Lumafield performed a 3-D CT scan of the chip for me, revealing six layers of complex wiring hidden inside the ceramic package. Moreover, the chip has nearly invisible metal wires connected to the sides of the package, the spikes below. The scan also revealed that the 386 has two separate power and ground networks: one for I/O and one for the CPU's logic.

• Chris Aldrich ☛ Cleaned Oild and Adjusted 1971 Olympia SG 3 Standard Typewriter

  While I love having a larger face typewriter, I can already tell that I’m likely not going to be using this one as frequently as I do my elite and pica machines with more traditional typeface sizes. It sure is fun using it though. I can tell it’ll be a hit at the next local type-in.

• CNX Software ☛ Banana Pi BPI-F4 – An industrial Edge Hey Hi (AI) SBC powered by Sunplus SP7350 SoC with 4.1 TOPS NPU

  The Banana Pi BPI-F4 is a compact industrial-grade Edge Hey Hi (AI) development board built around the Sunplus SP7350 quad-core Cortex-A55 SoC with a 4.1 TOPS NPU. Compared to the SunPlus SP7021-based BPI-F2S SBC, the new BPI-F4 supports additional interfaces through terminal blocks and is suitable for Hey Hi (AI) vision, robotics, and control systems.

• Hackaday ☛ 2025 One Hertz Challenge: Estimating Pi With An Arduino Nano R4

  Humanity pretty much has Pi figured out at this point. We’ve calculated it many times over and are confident about what it is down to many, many decimal places. However, if you fancy estimating it with some electronic assistance, you might find this project from [Roni Bandini] interesting.

• Hackaday ☛ 3D Printing A Giant Beyblade Arena

  Beyblade spinning tops are pretty easy to find at toy shops, department stores, and even some supermarkets. However, the arenas in which the tops do battle? They’re much harder to come by, and the ones on sale in any given market often leave a lot to be desired. [LeftBurst] got around this problem by printing a grandiose Beyblade arena.