LoRa GNSS Compact Wearable Tracker Design

About the project

# Freelancer Project – Design and Prototype an Ultra-Compact LoRa GNSS Wearable Tracker ## Project Overview I am looking for an experienced RF/PCB engineer to design, prototype and validate an ultra-compact battery-powered wearable LoRa GNSS tracking device. This project includes the complete hardware development, mechanical enclosure, prototype assembly and test software. The objective is to obtain a manufacturable prototype that minimizes size, weight and power consumption while maintaining reliable RF performance. --- # Mechanical Concepts Please evaluate both concepts and recommend the most suitable one. ## Option A – Coin Shape * Maximum diameter: **25 mm** * Maximum thickness: **8 mm** * Rounded shape * Epoxy housing (hard or rubber-like finish) * Reinforced hole/eyelet for attaching a click ring or similar * USB-C connector located opposite the attachment hole ## Option B – Curved Rectangular Shape * Maximum dimensions: **50 × 15 × 15 mm** * Curved profile to better adapt to belts, straps or collars * Flexible or rigid-flex PCB if technically advantageous * Rounded ends * Epoxy housing (hard or rubber-like finish) * Integrated attachment solution The freelancer should recommend which concept offers the best compromise between size, weight, RF performance, manufacturability and battery life. --- # Hardware Requirements The device shall include: * Low-power MCU * LoRa communication * Multi-constellation GNSS receiver (GPS/Galileo/GLONASS/BeiDou preferred) * Rechargeable LiPo battery * USB-C charging * 9-axis IMU * Temperature sensor * Barometric pressure sensor (if space permits) * Battery charging and protection circuitry * Battery level monitoring (fuel gauge preferred) * RF tag allowing remote reading of the device unique ID * Low-power sleep capability The freelancer may recommend equivalent components if they improve performance or reduce size. --- # Operating Modes The hardware shall support: ### Mode 1 Deep sleep * No transmissions * Minimum possible power consumption ### Mode 2 On-demand transmission The device only transmits when requested. ### Mode 3 Heartbeat mode Automatic LoRa transmission every configurable number of seconds. Default interval: 20 seconds --- # Battery Performance The freelancer shall estimate the achievable autonomy for both proposed form factors. Target: * Maximum possible operating time * If technically feasible, at least 6 hours using GNSS with LoRa heartbeat transmissions every 20 seconds If this target is not achievable within the required dimensions, provide realistic alternatives and explain the trade-offs. --- # Test Software Production firmware is **not** required. Instead, provide simple demonstration/test software compatible with the selected hardware platform and development framework (it does **not** need to be Arduino if another SDK is more appropriate). The test software shall independently verify: * LoRa transmission * LoRa reception * GNSS positioning * Battery voltage and charge level * USB charging * IMU operation * Temperature sensor * Pressure sensor (if included) * RF tag ID reading * Deep sleep * Heartbeat mode * On-demand transmission Each hardware function should be individually testable. --- # Mechanical Requirements The enclosure should: * Be as small and light as reasonably possible * Have rounded edges * Be comfortable to wear * Be splash resistant where practical * Be epoxy encapsulated (hard or rubber-like finish) * Leave the USB-C connector accessible * Include an integrated attachment hole or eyelet The freelancer shall explain any compromises required between dimensions, battery capacity and RF performance. --- # Deliverables ### Electronics * Complete schematic * PCB layout * BOM with manufacturer part numbers * Gerber files * Pick & Place files * Assembly drawings * PCB source files (KiCad or Altium) ### Mechanical * Complete 3D enclosure * Native CAD files * STEP files * STL files ### Software * Hardware test software * Source code * Build instructions ### Documentation * Component selection rationale * Battery life estimation * RF recommendations * Assembly instructions * Manufacturing recommendations * Short validation/test report --- # Prototype Delivery The freelancer shall deliver **two fully assembled and fully tested prototypes**. The project price shall include: * PCB assembly * Programming * Functional testing * Mechanical assembly * Final validation Electronic components, PCB fabrication, batteries, enclosure manufacturing and shipping costs will be paid separately by the client. Before shipment, the freelancer shall provide a video demonstrating that both prototypes successfully perform all required hardware tests. --- # Proposal Requirements Please include: * Portfolio of similar projects * Experience with LoRa and GNSS RF design * Recommended form factor * Estimated final dimensions * Estimated weight * Estimated battery autonomy * Estimated engineering schedule * Fixed project price * Any recommendations to improve the design The goal is to establish a long-term collaboration for future hardware revisions and commercial versions.

Skills required