Emirhan Sönmez

A programmable lab power supply needs a control unit that drives a graphical front panel, talks to a host over the network, and can be updated in the field without bricking.

STM32H750 firmware built on a board support package I wrote from scratch — QSPI flash, SDRAM, LTDC and DMA2D for the display pipeline, GPIO and rotary encoder input — on a FreeRTOS architecture carrying RS485, Ethernet over LwIP, and an embedded server.

Firmware ships as custom-packaged images with checksum validation, version metadata and AES-based cryptographic protection, verified before anything is committed to flash.

The power supply platform needed programmable digital I/O able to drive both internal logic and external industrial loads from a single board.

An STM32-based 8-channel digital I/O board with 5 V / 100 mA internal outputs and 5–32 V / 500 mA external outputs, with control firmware over SPI, UART and RS485 alongside ADC, DAC and PWM peripherals.

A flyback-based 12 V to 5 V conversion stage lets the board run directly from an external supply rail, with no separate power module in the chain.

Deployed embedded controllers need a firmware update path that cannot leave the device unbootable if an update fails halfway through.

Copy-to-RAM and execute-in-place bootloaders that load application firmware from external QSPI flash with rollback support, on a FreeRTOS platform with Ethernet (LwIP with DHCP) and an embedded HTTP server.

Updates arrive over HTTP or USB and are verified against SHA256 and version metadata before activation, with a companion Python utility handling firmware packaging.

Measuring current on a spinning rotor rules out wired instrumentation entirely.

An ESP32-based wireless measurement module with dual 20 A current sensing units, battery monitoring and charging circuitry, and onboard 3.3 V regulation, integrated on a custom PCB.

Rotor-side current data reaches the monitoring host wirelessly, with the whole node running from its own managed battery supply.

Off-the-shelf rotary encoders are awkward to mount on a research motor and costly to replace when a test damages one.

A rotary magnetic encoder using three orthogonally placed TMAG5170 Hall sensors for angular position, read over SPI by an STM32, laid out on a circular PCB shaped for direct motor mounting.

Position data leaves the board as an RS422 differential signal, so it survives the electrical noise of a running drive.

A comfort monitoring and data logging build with no HAL permitted — every peripheral configured register by register.

STM32F746 firmware written bare-metal at register level: I²C environmental and motion sensors on interrupt-driven sampling, SD card logging over SDMMC, and an LCD interface driven from SDRAM framebuffers.

Logged data is written with AES-based protection, with UART instrumentation for debugging the full stack from sensor to storage.

Build a switchable BCD counter out of discrete logic — no microcontroller shortcuts allowed.

Frequency dividers, multiplexers and BCD counters assembled from flip-flops and combinational logic gates.

Modelled and verified in LTspice and Logisim before hardware implementation, so the board was tested against a simulated reference rather than trial and error.

Heart and lung sounds sit at amplitudes and frequencies that need dedicated analog conditioning before they become audible.

An analog signal chain using multi-stage op-amp amplification and active filtering tuned to biomedical signal bands.

Filtered heart and lung sounds are reproduced through headphones by a dedicated audio output stage — fully analog, no digital signal processing.