Embedded

A cropped sensor view handing pan authority off to a physical gimbal

Two Pans, One Stick: Blending a Digital Crop Pan with a Physical Gimbal

A long-range zoom camera pans two ways at once — by sliding a crop window across the sensor, and by physically rotating the gimbal underneath it. Here’s how to make one joystick drive both so the operator never feels the seam, the maths of the handoff, and the per-axis bug that kept the gimbal rolling after the stick let go.

Hunting an undocumented AHRS on the serial bus

Which tty Is the AHRS? Hunting an Undocumented Serial Device on a Jetson

A small AHRS was wired to a Jetson over USB, but nobody wrote down which serial port. Here’s how I tracked it down by its protocol instead of its name, fell into the classic dialout permissions trap, and decoded its orientation stream into human-readable numbers.

H.264 vs H.265 vs AV1 end-to-end latency on Jetson Orin — grouped bar chart

H.264, H.265, and AV1 on Jetson Orin: A Real Hardware Latency Benchmark

A rigorous per-stage latency benchmark across H.264, H.265, and AV1 hardware codecs on NVIDIA Jetson Orin (JetPack 6), measuring encode, wire, and decode separately at FHD and HD resolutions. AV1 wins end-to-end at 104 ms FHD / 86 ms HD. H.264 is the worst choice despite being the oldest: its nvv4l2decoder holds ~4 frames in an internal DPB buffer, adding 130–170 ms of hidden latency. Wire latency is governed by parse-element lookahead, not byte volume. Clock sync achieves ±234 µs via chrony. Full pipeline source, CSVs, and reproduction steps included.

Cleaning Up, Pipelining, and Bake-Testing the STM32H750 Tracker

A sequel to the first STM32H750 tracker post. After the C++ port was proven in production, I spent a week of evenings cutting dead vendor code, splitting the algorithm out to host for unit tests, wiring the LCD SPI through DMA to let the CPU run the tracker in parallel with the blit, unlocking the camera’s real frame rate, chasing a subtle BB-drift bug back to a too-wide SAD search, and finally building an offline A/B harness that compares SAD, NCC, and MOSSE on four synthetic scenarios so the next tracker port is a data decision, not a vibes one.

Building a Template-Matching Tracker on an STM32H750: What Worked, What Didn't

A long, honest retrospective on turning a WeAct STM32H750 board, a cheap OV7725 IR camera, and an Xbox controller into a live template-matching tracker. Every dead end, every wrong assumption, every fix — and what I’d do differently next time.

Scripted Hardware Testing for PX4 — MAVLink Shell, Docker, and pymavlink

How to script PX4 hardware verification using pymavlink’s SERIAL_CONTROL protocol over a USB connection — download CI firmware, flash from the command line, and run NSH commands programmatically. No QGroundControl required.