🌴 Outdoor BLE-connected UV sensor keychain 🗝

power LiPO
wireless BLE
sensor UV Index
mcu nRF52
battery life 5 days
bom items 13
bom cost USD $50.47
vendors 4
completed July 2019




Lessons learnt

Good practices to continue for future projects

  • Mark polarity for power connectors to safe guard against reverse polarity. E.g. JST connector should have + and - labels on silkscreen
  • Buy good quality LiPo / battery and power connectors E.g. JST connectors


For next iteration

  • Do not use modules as they are big and bulky. E.g. MDBT42Q
  • Use DP3T to power on, wireless off and wireless on options instead of 2 switches
  • Use a smaller and brighter RGB LED
  • Use a single layer board with only SMD parts so that a housing can be catered for the battery at the back
  • Use a smaller rechargeable coin cell battery E.g. CR2450