Tastra Foods

About the role We are building a custom Vending Machine Controller (VMC) board in collaboration with Riosh Technologies (confirmed board components). You will be the primary firmware engineer responsible for hardware bring-up, motor/elevator control, and the machine UI (touch display). This is a high-impact role — you’ll own the embedded stack for our pilot vending machines and help define firmware standards for future machines. Key Responsibilities Bring up and validate the confirmed VMC board (RPI CM4-based compute / or equivalent module). Implement robust firmware for motors, sensors, elevator control, and vending sequences. Develop machine-side UI screens (LCD / touch) for vendor flow (welcome, vend, error, OOS, thank you). Implement comms & diagnostics (UART/SPI/I²C) and integrate with backend APIs (HTTP/MQTT). Implement logging, retry/recovery logic, watchdogs, and OTA-ready hooks. Work closely with Riosh (hardware partner) to validate schematics, pinouts, and run prototype tests. Provide detailed handover: source code, flashing instructions, PCB pin mapping, and test procedures. Provide short-term support (2–4 weeks) for bugs after delivery and assist integration testing. Confirmed Hardware Components (you will work with) Compute Module 4 (RPI CM4 or equivalent) — main processor & Wi-Fi. LTE Modem + SIM connector (cellular comms). RJ45 ethernet. Onboard Flash (storage) and LCD display for UI. Temperature sensor, IR sensor, limit switches. Motor driver(s) for motors/elevator. LEDs & switches for status/config. 24VDC power input, surge protection, regulators (3.3V/5V). PCB: 2–4 layers, 1.6mm thickness. (These components are confirmed by our hardware partner — candidate must be comfortable with bringing-up these exact modules.) Required Skills & Experience 3–8+ years in embedded firmware development. Strong C/C++ expertise; comfortable with ARM Cortex or RPi CM4 platforms (or ESP32/STM32 if relevant). Experience with FreeRTOS or comparable RTOS. Experience implementing motor control (DC/stepper), limit switches, IR sensors. Experience debugging with logic analyzers/oscilloscopes. Comfortable implementing UART/SPI/I²C, ADC, PWM, timers. Prior experience integrating cellular/LTE modules, Wi-Fi and ethernet preferred. Strong documentation and test case discipline.