Integration of Wix with Checkbox for order fiscalization

We are looking for an experienced Embedded developer to create energy-efficient firmware for a wearable device (form factor: chest strap) for monitoring psychophysiological state. The circuit design is complete, and development will be based on a development kit with subsequent transfer to a custom board.Stack and hardware base:MCU: Nordic Semiconductor nRF52840 or nRF5340.Development environment: nRF Connect SDK / Zephyr RTOS (strictly C/C++).Peripherals:Optical pulse sensor (PPG) — operates via I2C.6-axis inertial sensor (IMU accelerometer + gyroscope) — operates via SPI.Haptic motor driver (LRA 1030) — controlled via PWM.External SPI Flash memory for cyclic logging.Work scope by stagesStage 1: Bring-up, peripheral drivers, and BLE telemetryGoal: Bring the hardware to life, set up stable data collection, and transmit it to a smartphone/PC.Configure I2C and SPI buses using DMA (Direct Memory Access) to offload the processor.Write/integrate drivers for PPG and IMU (configure polling frequency, sensor FIFO buffers).Deploy a custom BLE profile (GATT service) for real-time transmission of raw data from sensors.Basic initialization of PWM for controlling the haptic LRA motor (launch test vibration patterns).Stage 2: Algorithmic layer (DSP and multi-level feedback logic)Goal: Implement mathematical signal processing directly on the chip (Edge Computing) and device reaction logic.Implement algorithms for filtering motion artifacts: clean the PPG signal using accelerometer data (IMU).Extract R-R intervals (HRV) from the cleaned PPG signal.Implement 4-level system stability logic:Drift Level: Track gradual changes in HRV and breathing.Prediction Level: Calculate a mathematical trend for deterioration.Micro-correction Level: Generate barely noticeable haptic patterns on the LRA motor when a target data pattern is detected.Hardware Reset Level: Implement safety logic (high-intensity haptic pulse at critical metrics).Stage 3: Energy saving, logging, and fault toleranceGoal: Prepare the device for autonomous operation from a miniature battery and ensure "24/7" stability.Deep optimization of energy consumption. Put the MCU into sleep mode (System ON/OFF) between measurement cycles. The processor should wake up only on interrupts from sensor FIFO buffers or a timer.Write a fault-tolerant file system in external SPI Flash (e.g., LittleFS) for autonomous cyclic log saving.Configure a hardware watchdog timer to prevent firmware hangs.Requirements for the performer:Experience in commercial development for Nordic chips (nRF52/nRF53) of at least 3 years.Proficient in Zephyr RTOS and debugging tools (Segger Embedded Studio / VS Code, J-Link).Understanding of digital signal filtering principles (DSP) and low-power design.Having your own debugging kit (nRF52840-DK or similar) for starting work is welcome.Work format:Milestone payments with results documented on GitHub. Please indicate your hourly rate or approximate cost and timeline estimates for each of the three stages.

Need a Wix specialist for website layout based on Figma design. There is a ready website design in Figma. It needs to be implemented in Wix with high quality, closely following the layout. Requirements: transfer the design from Figma to Wix; adapt all pages; set up desktop and mobile versions; ensure correct display on different devices. Preference will be given to freelancers with experience working with Wix. Please send your portfolio with completed projects.

General information It is necessary to develop a simple minimalist web system, the main purpose of which is to maintain a client database, create appointments for visits, and automate the process of confirming visits via SMS, sending one-time links through the API from the service itself. The project is being developed in stages. In the first stage, it is necessary to implement only the basic functionality (MVP) so that the system can be used in real work. After launch and testing, it will gradually be expanded with new modules.Main functionality of the first stage User authorization; Client database; Creating and editing appointments; List of appointments (or a simple calendar); Switching between points of sale; Integration with the SMS operator via API; Sending SMS with any text or link for visit confirmation; Confirmation or cancellation of the visit by the client via a one-time link; Displaying the confirmation status directly next to the client's appointment. At the initial stage, instead of a full calendar, the use of a simple list of appointments by days is allowed. Each day should contain a chronological list of bookings indicating the time, client's name, service, employee, and confirmation status. Later, this list can be replaced with a full calendar without changing the system structure. The system must have the ability to switch between points of sale. Each point of sale has its own list of appointments (or calendar), but they all use a common client database.

Project: landing page for student recruitment for a manicure/pedicure academy based at LÁSKA Beauty Studio (Frýdek-Místek, Czech Republic). Website languages: Czech (main) + Ukrainian (language switch). Goal: application for the course through the form on the website Target audience and course information (programs, prices, target audience profiles): will be provided to the contractor after the work starts. Landing page structure: in the attached file (ready to discuss) Design references Palette and style — brand book will be provided Landing pages that are liked: thezeny.cz, makeupinstitute.cz Functional requirements Responsive layout (desktop/tablet/mobile). Language switch CZ/UA (all content duplicated). Application form with validation Google Maps with the studio in Frýdek-Místek. SEO markup + microdata Course/LocalBusiness. Consent for personal data processing (GDPR).

Looking for an experienced Go developer to participate in a project. Confident knowledge of Go, experience in backend/API development, working with databases, and Git is required. Experience with Docker, Kubernetes, and microservices architecture will be a plus.