🌳 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




For future improvements

  • (Schematci) Add functional logical blocks in schematic to use similar circuits in future versions or other projects
  • (Manufacturing) Use stencil SMD soldering with SMD components only if it is necessary. Else, use a PCB assembly service.
  • (Manufacturin) Use minimum number of through-hole components
  • (Manufacturing) Check Gerber file format with the PCB manufacturer before rendering them
  • (Manufacturing) Check F.Paste and B.Paste layers for SMD stencil pattern
  • (Testing) Pull out every single MCU pin as a test point for the first version of the project.
  • (BOM) Always buy buffer number of components. Image is from the book Designing Electronics That Work by Hunter Scott.
  • (Layout) Make the PCB routing symmetrical for LED positions and connector slots
  • (Case) Ensure the length is not too long to prevent bending of the material
  • (Case) Use wider ventilation holes with wider spacing between each of them
  • (Case) Use less clearance for connector slots. Take note of finger access
  • (Case) Use other shapes for connector slots E.g. rounded corner or trapezoid
  • (Case) Use shape binder for seperation plane bends
  • (Case) Use a counter sunk screw head
  • (Case) Make the screw lug's initial length be wider to contain the screw head so that it can sink into the surface
  • (Case) Try a snap-fit enclosure
  • (Manufacturing) Use SMD components only on top layer for one-step manual SMD stencil soldering process
  • (Layout) Place a writable area on the silkscreen to note down LoRa node address, PCB number, frequency or other info
  • (Layout) Add a surface mount PCB test point for VBAT, VBUS, 3.3V, 5V, GND and SPI points.
  • (BOM) Use a smaller SSD1306 I2C OLED display instead of E-Ink. It's cheaper and easier to source and buy.
  • (Testing) Check with 3 PCBs to conclude whether it is a design issue or a soldering / manufacturing / assembly issue
  • (Testing) Power it with current limiting power supply unit only. Check all the power test points such as VBAT, VBUS, 3.3V, 5V, GND.