#Embedded
VM Sees the Dongle but Has No Internet Without a Windows ECM Driver
After passing a USB LTE dongle through to a Windows VM, the system sees the device but no network adapter appears. The cause is neither the SIM nor port passthrough, but the dongle exposing a CDC ECM interface that Windows has no built-in driver for, along with storage-mode pitfalls and dhclient overwriting the host's resolv.conf.
Reading an Unknown Modbus Device: Verify Before Interpreting
My notes on tracking down an undocumented device on an RS485 bus, from scanning baud rates and addresses one combination at a time to proving which registers hold live values and which are dead, and the lesson that guessing a device's type from number patterns alone can lead to months of misinterpretation.
reCamera + Gimbal: RISC-V Cross-Compilation, CAN, and Node-RED
reCamera is an AI camera on a RISC-V chip mounted on two brushless axes, with rotation controlled over CAN bus at a resolution of 0.01 degrees. This article covers cross-compiling C for riscv64 musl, uploading to the device with scp, the CAN frame structure for motor control, reading back the 15-bit encoder, finding motor zero using current, a Node-RED dashboard + PID + auto-track, and STP files for 3D-printing the housing.
Reading a DTSU666 3-Phase Meter with Raspberry Pi over Modbus RS485
Notes on connecting a DTSU666 Smart Power Sensor to a Raspberry Pi over RS485, reading 3-phase electrical measurements from multiple meters using Modbus RTU, decoding 32-bit floats correctly, and storing them in SQLite/MySQL before exporting through MQTT and a REST API, including a negative-value bug I ran into myself
Reading Modbus RTU over an RS485 Gateway Without Phantom Values
Connecting multiple Modbus RTU meters/sensors on an RS485 bus through a serial-to-Ethernet gateway can produce phantom values, incorrect readings, or devices that do not actually exist — because a transparent gateway uses RTU-over-TCP, which requires assembling frames and calculating CRC yourself, and validating every reply. This article covers the rules I learned from doing it.
USB in WSL2 with usbipd-win — Real Hardware for Linux on Windows
WSL2 cannot see USB devices because it is a VM without a USB controller — usbipd-win passes devices from Windows directly to the WSL kernel with 3 commands, list/bind/attach, plus lessons from actual use: attachments drop when unplugged, the CRLF trap, and USB modems taking over the default route