Board + Layout for 2xTemp/Humidity Sensor

  • Hey everyone,

    after getting so many valuable informations in this forum, I think it's my time to give something back.
    Don't know if anyone needs it, but here are the facts:

    • Sensor is powered by 2xAA batteries
    • using a SI7021 Temp-/Humidity sensor
    • using a DS18b20 Temp sensor
    • battery monitored
    • status LED
    • drawing about 4,5µA (0,0045mA) while sleeping, about 1-3mA while sending, 17mA during boot up
    • using really cheap parts like a usual Atmega328p-pu microcontroller and the mentioned SI7021

    First of all, some photos:
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    The used batteries are "N" or "LR1" so you can guess the size of the pcb

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    Top side of the pcb

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    Bottom side of the pcb

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    Current draw in sleep mode, where the blue "30" on the right side is 30µA. (The device used for measuring might be old, 1960, but double checked and calibrated with a 600€ Fluke 289 Multimeter which, unfortunately, is not mine 😛 )

    I integrated a push button for current saving, so it needs to be pushed before connecting the pcb to the batteries and released about 3 seconds after boot up.
    The LED indicates the begin and the end of the main loop in my code.

    If anyone is interested, I can provide my PCB files (although it's not that hard to make your own from the photos 😉 ) and the sketch I use.

    Have a good day everyone and so long

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