🌳 Outdoor LoRa-GPS tracker with E-Ink display 🔑

power 18650
wireless LoRa,
sensor GPS, E-Ink
mcu SAMD21G18
bom items 82
bom cost USD $78.93
vendors 6
completed July 2022

Lessons learnt

Good practices to continue for future projects

  • Add functional logical blocks in schematic to use similar circuits in future versions or other projects
  • Use stencil SMD soldering with SMD components only if it is necessary. Else, use a PCB assembly service.
  • Use minimum number of through-hole components
  • Check Gerber file format with the PCB manufacturer before rendering them
  • Check F.Paste and B.Paste layers for SMD stencil pattern
  • Pull out every single MCU pin as a test point for the first version of the project.
  • Always buy buffer number of components. Image is from the book Designing Electronics That Work by Hunter Scott. Always buy buffer number of components. Image is from the book Designing Electronics That Work by Hunter Scott.

Next iteration improvements

  • Make the PCB routing symmetrical for LED positions and connector slots
  • Ensure the length is not too long to prevent bending of the material
  • Use wider ventilation holes with wider spacing between each of them
  • Use less clearance for connector slots. Take note of finger access
  • Use other shapes for connector slots E.g. rounded corner or trapezoid
  • Use shape binder for seperation plane bends
  • Use a counter sunk screw head
  • Make the screw lug's initial length be wider to contain the screw head so that it can sink into the surface
  • Try a snap-fit enclosure


For next iteration

  • Use SMD components only on top layer for one-step manual SMD stencil soldering process
  • Place a writable area on the silkscreen to note down LoRa node address, PCB number, frequency or other info
  • Add a surface mount PCB test point for VBAT, VBUS, 3.3V, 5V, GND and SPI points.
  • Use a smaller SSD1306 I2C OLED display instead of E-Ink. It's cheaper and easier to source and buy.

Board bring-up

  • Check with 3 PCBs to conclude whether it is a design issue or a soldering / manufacturing / assembly issue
  • Power it with current limiting power supply unit only. Check all the power test points such as VBAT, VBUS, 3.3V, 5V, GND.

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Project Attributes
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LoRa : SX1276 / 1278
battery : 1000mA Li-on
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SAMD21 LoRa Development Board with GPS developer 2018 microcontroller : ATSAMD21E18A-AU
GPS : Quectel L80 GPS module
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battery : LiOn


LoRa Antenna







The Gantt Chart below indicates the actual time taken to complete this project. It can be used as a rough guidline when duplicating or iterating similar projects in the future.