Expert PCB/RF/Firmware Engineer Needed – Solar-Powered GPS + LoRa Livestock Ear Tag & Gateway

# Job Title **Expert PCB/RF/Firmware Engineer Needed – Solar-Powered GPS + LoRa Livestock Ear Tag & Gateway** ## Project Overview We are developing a **production-ready smart livestock ear tag and matching long-range gateway system**. The first version will be designed primarily for cattle, but the hardware must be kept as **small and lightweight as possible** so that future versions can also be used on goats. The most important engineering priorities are: 1. **Extremely low power consumption** 2. **Reliable long-range LoRa communication** 3. **Very lightweight/compact tag design** 4. **Reliable solar charging** 5. **Production-ready hardware, not just a prototype** We have an existing commercial reference device that can be used for benchmarking physical size, power strategy and functionality, but the new product must be **designed from scratch with original schematics, PCB layout and firmware**, containing only the functionality listed below. --- # 1. Smart Ear Tag Requirements The animal tag must include: ### GPS / GNSS * Reliable multi-constellation GNSS positioning * GNSS must be power-gated when not in use * Adaptive location collection based on animal movement and battery/solar condition * Initial target: * approximately 10–15 minute fixes while the animal is active * approximately 30–60 minute fixes while stationary * temporary 1–2 minute tracking during recovery/alarm mode * Store positions locally and batch them for transmission where this saves energy ### LoRa – 863–870 MHz * Main long-range tag-to-gateway communication * Prefer SX1262/LLCC68-class radio or another suitable low-power production component * Design for Uganda/EU 868 MHz operation * Initial normal transmission target approximately every 10 minutes * Immediate transmission on important events * Configurable transmission intervals * Compact binary payloads * LoRaWAN Class A is preferred unless there is a well-justified better architecture **RF target:** * **5 km or greater open rural line-of-sight design target** * **Reliable ≥1 km farm coverage target** with correctly positioned gateways in hilly areas with sparse vegetation We understand that terrain affects RF range; therefore the engineer must provide a proper RF link budget and antenna strategy rather than simply guarantee an arbitrary distance. ### Bluetooth Low Energy BLE is required for: * device provisioning * configuration * diagnostics * retrieving engineering/raw data * secure OTA firmware updates when physically near the animal/tag A Nordic nRF52-class MCU or an equivalent low-power BLE MCU may be proposed. BLE is not intended for kilometre-scale farm communication. ### Accelerometer Ultra-low-power 3-axis accelerometer such as Bosch BMA400 or equivalent. Requirements: * always-on low-power monitoring * approximately 12.5–25 Hz configurable sampling * raw X/Y/Z access * FIFO * wake-on-motion / activity interrupts * orientation information It will be used for: * animal activity analytics * grazing/resting/walking patterns * unusual movement * inactivity * possible detachment/separation detection * intelligent GNSS power management ### Local Storage Include low-power flash memory sufficient for: * stored GNSS history * offline telemetry * accelerometer event windows * diagnostic logs * firmware-update image Approximately **4–8 MB usable storage** is expected unless the engineer recommends otherwise. ### Solar Power The tag must be solar powered. Requirements: * high-efficiency miniature solar panel * proper low-power solar energy-harvesting / MPPT architecture * reliable battery charging under variable sunlight * battery and solar health monitoring * reverse-current protection * overcharge/deep-discharge protection * charging safety A BQ25570-class energy-harvesting solution or a better justified alternative may be proposed. The solar connection should be mechanically reliable and should not rely only on pressure contacts. ### Battery Target: * approximately **200–300 mAh rechargeable LiPo** * protected battery * temperature-safe charging * no routine battery replacement The design should target approximately **30 days of operation without useful solar charging under the agreed normal tracking profile**, to be confirmed through an actual measured power budget. ### Solar/Battery Telemetry The tag should report: * battery voltage * battery % * charging state * solar-input/charging condition * abnormal battery decline * firmware/device diagnostics --- # 2. Tag Power Management Energy efficiency is the most important design requirement. The engineer must design and document all operating states, including: **Normal mode** * accelerometer always monitoring * periodic GNSS * LoRa approximately every 10 minutes * BLE normally asleep **Stationary mode** * automatically reduce GNSS frequency * maintain activity monitoring and LoRa heartbeat **Recovery/alarm mode** * immediate GNSS fix * immediate LoRa transmission * temporarily increase GNSS/LoRa reporting frequency **Low-battery mode** * reduce GNSS and radio activity * preserve essential tracking and health telemetry The final design must include a measured/calculated power budget for every major state. --- # 3. Physical Tag Requirements The device will be mounted on an animal's ear. Target requirements: * **≤20 g complete tag preferred** * Weight includes PCB, battery, solar panel and enclosure * As thin and compact as realistically possible * Low centre of gravity close to the ear attachment point * Rounded enclosure with no unnecessary snag points * Internal antennas * No exposed USB/programming connector * IP67 minimum, IP68 preferred * UV-, rain-, mud- and outdoor-resistant The PCB should be designed with future goat use in mind even though V1 is initially for cattle. --- # 4. RF and Antenna Requirements This is an RF-sensitive product. The engineer must be comfortable with: * 868 MHz antenna design * 2.4 GHz BLE antenna design * GNSS antenna design * RF matching networks * controlled impedance * ground planes * antenna keep-outs * ground stitching * body/enclosure detuning * VNA-based antenna tuning * RF link-budget calculations A custom PCB/FPC antenna may be proposed where appropriate. Prototype boards should include temporary RF measurement points/connectors. Final antenna tuning must be performed with: * actual PCB * battery * solar panel * final/representative enclosure not only on a bare PCB. --- # 5. Gateway Requirements The project also includes the **matching farm gateway**. The gateway must receive LoRa telemetry from the tags and forward it to our backend. ### Gateway LoRa Preferred architecture: * SX1302/SX1303-class multi-channel LoRa concentrator or equivalent * 863–870 MHz * high-quality external LoRa antenna * outdoor long-range communication Target: * **5 km+ open rural line-of-sight link with correctly engineered tag/gateway antennas** * reliable coverage of farms around 1 km across, including moderately hilly terrain through correct gateway placement ### Gateway Backhaul Gateway should support: * Ethernet * Wi-Fi * optional 4G/LTE modem/interface for remote farms Data should be forwarded through a documented protocol such as: * MQTT * HTTPS * or another justified open interface ### Bluetooth Gateway should include BLE for: * local commissioning * setup * diagnostics ### Offline Operation The gateway must have local storage/buffering. If internet connectivity disappears: * tag packets must continue to be received * data must be stored locally * stored data should automatically synchronize when internet returns ### Solar Power The gateway should support a completely off-grid installation using: * external solar panel * LiFePO₄ battery * MPPT/solar charge controller * regulated power system * surge/lightning protection The engineer must calculate the gateway power budget and recommend: * solar panel size * battery capacity * charge-controller specification ### Outdoor Deployment Gateway design should support: * IP65/IP67 equipment enclosure * pole/mast installation * elevated external antenna * lightning/surge protection * grounding * low-loss RF cable --- # 6. Security Required: * unique device IDs * unique per-device security credentials * encrypted/authenticated tag communication * secure BLE provisioning * signed firmware updates * secure boot where supported * no fleet-wide universal secret key * firmware versioning and rollback/recovery --- # 7. Data Required From Tag The system must provide our backend with at least: * device ID * sequence number * latitude * longitude * GNSS timestamp * location accuracy/fix quality * activity summary * raw accelerometer event data when requested * battery voltage/percentage * solar/charging status * firmware version * diagnostic flags * gateway RSSI/SNR metadata All data formats and protocols must be fully documented. We will develop the web/mobile livestock-management platform separately. --- # 8. PCB Requirements ### Ear Tag PCB * 4-layer minimum * optimized for extremely low power * compact layout * production SMT-ready * proper RF grounding/layout * factory test pads * programming/debug interface * battery/solar test points * antenna matching networks * 3D mechanical model ### Gateway PCB Can use proven concentrator modules/reference designs where this improves reliability and reduces development risk. Must still provide a complete production-ready gateway design and integration. --- # 9. Required Deliverables The final project must include: * complete system architecture * component-selection report * tag power budget * gateway power budget * LoRa link budget * complete editable schematics * PCB source files * PCB stack-up * Gerbers * drill files * pick-and-place files * assembly drawings * 3D STEP files * complete BOM with manufacturer part numbers * alternative components for critical parts * full tag firmware source code * full gateway firmware/software source code * bootloader / BLE OTA implementation * tag-to-gateway communication protocol documentation * backend packet/interface documentation * factory programming procedure * factory test procedure * antenna/RF design documentation * prototype bring-up support * first prototype PCB revision corrections * final corrected production files All project source files must be handed over. --- # 10. Prototype & Validation Support We do not want only Gerber files. The selected engineer must support the first manufactured prototypes and help validate: * tag power consumption * solar charging * GNSS performance * LoRa range * BLE * accelerometer * flash/storage * antenna performance * gateway/tag interoperability * offline buffering Any schematic, PCB-layout, footprint or firmware errors attributable to the design should be corrected as part of the project. --- # 11. Experience Required Please apply only if you have strong practical experience with several of the following: * multi-layer PCB design * low-power embedded hardware * LoRa / sub-GHz RF * GNSS/GPS trackers * Bluetooth Low Energy * antenna/RF matching * solar-powered IoT devices * battery management * embedded C/C++ * production hardware * prototype bring-up and debugging Experience designing **compact battery/solar trackers or wearable/asset-tracking devices** is highly preferred. --- # Application Requirements Please include: 1. Examples of multi-layer PCBs you personally designed. 2. Examples of any LoRa/sub-GHz RF products you have built. 3. Any solar/battery-powered product experience. 4. Any GNSS tracker experience. 5. PCB design software you use. 6. RF test equipment you have access to, especially VNA/spectrum analyzer. 7. How you would approach achieving a 5 km open-field LoRa link from a small battery-powered tag. 8. A brief explanation of how you would minimize GNSS + LoRa power consumption in this design. 9. Estimated project timeline. 10. Your proposed fixed price. **Please do not apply if your experience is limited to basic Arduino/module-based projects. We require a production hardware engineer who can take the product from architecture through prototype validation and manufacturing files.**