2026-07-31 15:41:34
I’ve recently been working on a mechatronics project that involves constructing an X-Y cartesian motion system. I opted to use stepper motors to drive each axis, and timing belts and pulleys for translating the rotational torque of the steppers into linear motion. The timing belts need to be anchored to the component that is being actuated, which in this case is the carriage on the linear rails. Though matching toothed clamps exist, it is common, particularly in DIY projects, for timing belts to be fastened using zip ties or custom clips.
2026-07-27 15:41:34
Disclaimer: this post contains spoilers for Christopher Nolan’s 2026 depiction of The Odyssey. If you are planning to watch the movie, I would recommend doing so prior to reading, even if you are already familiar with the story. I’ve spent most of my career leading teams, including serving as CTO at Golioth prior to our acquisition by Canonical. Over the years I’ve tried to commit a significant portion of my time to listening to feedback from individuals on those teams, reflecting on my own decisions and motivations, and seeking advice and guidance from those who have been successful leaders.
2026-05-30 15:41:34
It has been more than two years since I bought a Pinecil soldering iron and wrote about soldering the breakout board and accessing the UART. I’ve been doing more work with the Pinecil as of late following the addition of upstream support for the Bouffalo Lab BL706 MCU in Zephyr (big shout out to @VynDragon, @will-tm, @josuah, and everyone else who has been contributing to the upstream Bouffalo Lab efforts!).
2026-04-16 15:41:34
In my recent post on the PSA Crypto API, I demonstrated the use of the API on two different MCUs: the nRF52840 and the ESP32-S3. In the case of the former, the ECDSA signature operation was eventually executed in a closed source library that manages communication between the Arm Cortex-M4 processor and the Arm TrustZone CryptoCell 310 security subsytem. Readers that ventured down the rabbit hole of links in the post may have noticed that there are variants of the nrf_cc310_mbedcrypto libraries for hard-float and soft-float.
2026-04-10 15:41:34
Arm’s Platform Security Architecture (PSA) was released in 2017, but it was two years until the first beta release of the PSA Cryptography API in 2019, and another year until the 1.0 specification in 2020. Aimed at securing connected devices and originally targeting only Arm-based systems, PSA has evolved with the donation of the PSA Certified program to GlobalPlatform in 2025, allowing non-Arm devices, such as popular RISC-V microcontrollers (MCUs), to achieve certification.
2026-03-01 15:41:34
Below are two X.509 certificates. The first is the Certificate Authority (CA) root certificate, and the second is a leaf certifcate signed by the private key of the CA. ca.crt.pem -----BEGIN CERTIFICATE----- MIIBejCCASGgAwIBAgIUda4UvlFzwQEO/fD0f4hAnj+ydPYwCgYIKoZIzj0EAwIw EjEQMA4GA1UEAxMHUm9vdCBDQTAgFw0yNjAyMjcxOTQ3NDZaGA8yMTI2MDIwMzE5 NDc0NlowEjEQMA4GA1UEAxMHUm9vdCBDQTBZMBMGByqGSM49AgEGCCqGSM49AwEH A0IABKL5BB9aaQ2TtNgUymEsa/+s2ZlTXVll0N22KKWxh0N/JdgHcjrKfzqRlVrt UN2GXdvsdLOq15TxBq97WvE07lKjUzBRMB0GA1UdDgQWBBTAVEw9doSzY1DuPVxP EnwEp/+VJDAfBgNVHSMEGDAWgBTAVEw9doSzY1DuPVxPEnwEp/+VJDAPBgNVHRMB Af8EBTADAQH/MAoGCCqGSM49BAMCA0cAMEQCIHrSTk/KJHAjn3MC/egvfxMM1NpG GEzMB7EH+VXWz7RfAiAyhwy4E9hc8/qsTI+4iKf2o/zMRu5H2GNJOLqOngglbQ== -----END CERTIFICATE----- leaf.crt.pem -----BEGIN CERTIFICATE----- MIIBHjCBxAIULE3hvnYxU91g9c9H3+uGCSqXi4MwCgYIKoZIzj0EAwIwEjEQMA4G A1UEAwwHUm9vdCBDQTAgFw0yNjAyMjcxOTQ3NDZaGA8yMTI2MDIwMzE5NDc0Nlow DzENMAsGA1UEAwwEbGVhZjBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABKDZ21Yh +1AQp1TrxrS8FquIVEHrFRSXncX9xl5vVhZFqvblzTp2Tg7TER5x7rHG1TIqQL1z xDX4TB+nZOWkyAcwCgYIKoZIzj0EAwIDSQAwRgIhAMeo5t2d1RWL/SB0E+mvvIZP jFT0wDWX1Bm26MtxRcf9AiEApG96fs70WF1JliFgzkTiNvbG7Gj4SvErZ9nNX/Lr PnA= -----END CERTIFICATE----- If you downloaded these certificates, you could visually see that the latter references the former as its Issuer.
