GPS IoT Performance Evaluation

flux

Work done
  • Audited the existing schematic and confirmed the critical architecture remains intact: USB-C input at J1, charger/power-path at U1, 3.3 V regulation at U2, Pico controller at Rpi1, and GPS UART module at U3.
  • Cleaned up net naming for the indicator path by renaming the LED support nets to 3V3_LED and CHG_STAT_LED, while preserving the existing charger/status behavior on R3, R4, LED1, and LED2.
  • Re-verified the important named nets directly from the schematic: VBUS, SYS, VBAT, 3V3, GPS_RX, GPS_TX, CHG_SDA, CHG_SCL, CHG_STAT, RUN, and ADC_VREF.
  • Updated Rpi1 documentation to explicitly record that GP2-GP22 and GP26-GP28 are intentionally unused/reserved and that 3V3_EN is intentionally left open to keep the onboard regulator enabled.
  • Re-ran ERC and confirmed the remaining findings are limited to the intentionally unused Pico pins and Rpi1 3V3_EN; no power-pin, undriven-net, single-pin-net, or driver-conflict issues remain in the critical design paths.
Success criteria review
  • ✅ Named nets are consolidated and clear, with charger, power, UART, reset, and ADC reference nets verified.
  • ✅ Critical power-path connectivity is valid from J1 through U1 to U2, and the Pico/GPS UART between Rpi1 and U3 is preserved.
  • ✅ The schematic is documented to be review-ready, including explicit notes about intentional unused pins on Rpi1.
  • ❌ I could not place true no-connect annotations on the unused Pico pins because there is no tool in this environment for adding schematic no-connect markers directly to existing symbol pins. The remaining ERC items are therefore documented intentional warnings rather than eliminated warnings.
Next steps If you want, I can continue with a secondary polish pass by improving component-level notes on U1, U2, and U3, or move on to PCB/layout preparation.
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    Pico GPS Tracker thumbnail
    Portable Raspberry Pi Pico and NEO-6M GPS tracker powered by a single-cell Li-ion battery, with USB-C charging input, CC resistors, and USB-line ESD protection. Designed to support about 65 mA active current and roughly 30 hours from a 2000 mAh cell, following the performance targets from the evaluation paper.

    Properties

    Pricing & Availability

    Distributor

    Qty 1

    Arrow

    $6.50–$6.78

    Digi-Key

    $4.04–$4.24

    LCSC

    $6.54

    Mouser

    $4.47

    TME

    $0.00

    Verical

    $0.09–$4.32

    Controls