Open Hardware/Modding: Raspberry Pi and Walnut Pi

posted by Roy Schestowitz on May 03, 2025

• CNX Software ☛ SO-ARM101 open-source dual robotic arm kit works with Hugging Face’s LeRobot

  SO-ARM101 “Arm Servo Motor Kit” is an open-source dual robotic arm kit that works with Hugging Face’s LeRobot robotics framework and is designed to interface with NVIDIA Jetson Hey Hi (AI) modules and computers. It is an update to the SO-ARM100 DIY open-source robotic arm kit introduced last year with LeRobot framework support. The new SO-ARM101 is still comprised of leader and follower arms but features improved wiring to prevent disconnection issues previously seen at joint 3, motors with optimized gear ratios, and a few functionality where the leader arm can now follow the follower arm in real-time, which will be used for reinforcement learning (RL) where a human can intervene and correct the robot’s actions.

• CNX Software ☛ Walnut Pi 2B is an Allwinner T527 octa-core SBC with Raspberry Pi 5 form factor and interfaces

  Walnut Pi 2B is a single board computer (SBC) powered by an Allwinner T527 octa-core Cortex-A55 SoC with a built-in 2 TOPS Hey Hi (AI) accelerator that closely follows the Raspberry Pi 5 design for compatibility with most HAT+ expansion boards and accessories. The Walnut Pi 2B SBC ships with 1GB to 4GB LPDDR4 RAM, an optional 32GB eMMC flash, and features a microSD card slot, gigabit Ethernet, four USB ports, a WiFI and Bluetooth module, MIPI DSI/CSI connectors, and the same PCIe FFC connector as found on the Raspberry Pi 5, and a 40-pin GPIO.

• The Register UK ☛ Raspberry Pi slices Compute Module 4 prices

  The Compute Module 4 (CM4) debuted in 2020 and was a departure from the DDR2 SODIMM form factor that had gone before it. Earlier this year, a fully loaded variant with 8 GB RAM and 32 GB of eMMC storage could be had for $95. The price is now $85. A non-wireless 4 GB Lite variant, with no eMMC storage, has dropped from $50 to $45.

• Jonas Hietala ☛ Jonas Hietala: Some VORON 0 mods

  I recently completed my VORON 0 build and I was determined to leave it as-is for a while and to start modding my VORON Trident…

  So before embarking om my larger Trident modding journey I decided to work on the VORON 0 just a little bit more.

• Ken Shirriff ☛ The absurdly complicated circuitry for the 386 processor's registers

  The groundbreaking Intel 386 processor (1985) was the first 32-bit processor in the x86 architecture. Like most processors, the 386 contains numerous registers; registers are a key part of a processor because they provide storage that is much faster than main memory. The register set of the 386 includes general-purpose registers, index registers, and segment selectors, as well as registers with special functions for memory management and operating system implementation. In this blog post, I look at the silicon die of the 386 and explain how the processor implements its main registers.

  It turns out that the circuitry that implements the 386's registers is much more complicated than one would expect. For the 30 registers that I examine, instead of using a standard circuit, the 386 uses six different circuits, each one optimized for the particular characteristics of the register. For some registers, Intel squeezes register cells together to double the storage capacity. Other registers support accesses of 8, 16, or 32 bits at a time. Much of the register file is "triple-ported", allowing two registers to be read simultaneously while a value is written to a third register. Finally, I was surprised to find that registers don't store bits in order: the lower 16 bits of each register are interleaved, while the upper 16 bits are stored linearly.

• Hackaday ☛ 3D Printed Spirograph Makes Art Out Of Walnut

  Who else remembers Spirograph? When making elaborate spiral doodles, did you ever wish for a much, much bigger version? [Fortress Fine Woodworks] had that thought, and “slapped a router onto it” to create a gorgeous walnut table.