🌲 Indoor Infrared receiver and transmitter with temperature sensor 🎐

power AA
wireless Infrared
mcu SAMD21G18
bom items 49
bom cost USD $9.71
vendors 2
completed September 2020

Lessons learnt

Good practices to continue for future projects

  • Do not reset annotations for components as previously annotated components might have already been associated with BOM
  • Do not copy and paste symbols for different parts of the schematic as they might copy over other field values
  • Refer to application circuit in datasheets to connect various passives
  • Consider pulling out some unused pins as pads if the board is to be used for future development and iteration E.g. Teensy
  • Consolidate shipping orders for parts and components so that fewer deliveries are made
  • Use a p-channel MOSFET for reverse polarity circuit protection


For next iteration

  • Use SMD components for IR receiver and emitter
  • Use standard 9-pin JTAG/SWD connector for burning the bootloader Use standard 9-pin JTAG/SWD connector for burning the bootloader
  • Use WiFi to control IR emission


Simple iterations that were implemented in this project because of the learnings from the previous projects

  • Added power annotations on the silkscreen
  • Used standard grid size for component placements and routing
  • Used standard text size
  • Used standard component sizes
  • Added a power on/off button
  • De-modularised to use only the micro-controller and no dev boards
  • Created a complete 3D rendering with all components
  • Pulled out some unused pins as test points
  • Added solder jumper points for circuit isolation

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Increasing IR LED range




Power and battery



EFM32 (not used in this project)



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.