Juan Chong

juan@chong ~$ ls -l

Juan Chong

Applications engineer working on MEMS inertial sensors. FIRST robotics volunteer, hardware tinkerer, and occasional console hacker.

Projects 7

A few things I’ve built, broken, or documented.

DC34 Badge Motion SensingWrite-up

Uses the DEF CON 34 badge’s existing accelerometer to work out whether its wearer is walking, standing, sitting, or not wearing it, and draws the answer on the idle screen.

EmbeddedRustXous

Details
  • Records labelled motion off the badge, trains a decision tree on a laptop, and compiles it back into the firmware. Inference runs on a RISC-V core with no floating-point unit.
  • Adds a shared sampler and a CSV data logger, and fixes the interrupt configuration that let the screen blank while the badge was being worn.

Read the write-up dc34-console

QuestNavActive

Turns a Meta Quest headset into a field localization sensor for FRC robots, streaming pose over NetworkTables.

FRCUnityLocalizationC#

Details
  • Uses the headset’s visual-inertial odometry, cameras plus the built-in IMU, to track position in 3D space, then publishes pose to the robot over NT4 across a wired Ethernet link.
  • Ships as a Unity app for the Quest plus a Java vendor dependency that feeds latency-compensated measurements into a swerve pose estimator.
  • MIT licensed and actively released, with setup guides and API docs at questnav.gg.

questnav.gg Source

N64 TAS ResearchOngoing

Reverse engineering the Nintendo 64 JTAG debug interface to make tool-assisted speedruns repeatable on real hardware.

Hardware HackingJTAGConsoles

Details
  • Probing the console’s debug pins to understand how the CPU and RCP can be halted and inspected.
  • Working with the TAS community to track down sources of desync between emulated and real runs.

Read the notes

80W CO2 Laser Cutter TeardownComplete

Testing, tuning, and modifying an inexpensive Chinese laser cutter bought during the 2020 face shield scramble.

LaserToolsHardware

Details
  • Measured actual tube output against the advertised rating.
  • Documented the electrical and mechanical fixes needed before the machine was trustworthy.

Read the review

Home Assistant on Raspbian + log2ramGuide

A Docker-based Home Assistant install that keeps chatty log writes off the SD card.

Home AssistantRPiDocker

Details
  • Runs the Supervisor stack on plain Raspberry Pi OS instead of the appliance image.
  • log2ram buffers logs in memory so a remote database outage can’t take the instance down.

Read the guide

Latitude 7280 Linux FixesGuide

Making Ubuntu genuinely usable on a Dell Latitude 7280 by fixing standby lock-ups and flaky WiFi.

LinuxGuides

Details
  • Kernel and firmware tweaks that stop the laptop from hanging when the screen blanks.

Read the guide

FRC 900, The ZebracornsVolunteer

Helping a local FIRST Robotics team develop ROS-based robot code, plus volunteering as a FIRST Technical Advisor at events.

RoboticsROSFIRST

Details
  • Mentoring students through sensor integration, odometry, and autonomous routines.

team900.org