Everything we've shipped in the last 2 years.

The complete R&D journey of the KalkMate smart calculator. The heart of the newest revision (v1.0.0, PCB v4) is a powerful dual-core ESP32-S3 chip running custom FreeRTOS-based firmware. The project strongly emphasizes cybersecurity and performance, introducing proprietary mechanisms like Signed OTA (ECDSA digital signatures), cryptographic key obfuscation, and safe Dual Boot architecture.

Ultrasonic distance meter on an ATtiny1616, measuring 10–50 cm with ~2.4 mm RMSE. A hybrid method: coarse time-of-flight from the 40 kHz echo envelope, refined by carrier phase (Goertzel filter), with NTC temperature compensation. Firmware in pure register-level AVR-GCC (no Arduino), ~0.9 mW sleep power. Bill of materials: €10.