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    Best posts made by klim

    • My 1AA battery sensor

      Hi, i want to present you my working but not really sexy looking single cell AA battery sensor. It is as it is - under development and was just made to get some experience about power consumption and physical size.
      I thought a lot about the type of battery to choose, but at the end i desisted to use an ordinary AA cell. I know about the advantages and disadvantages of different battery chemistry and types, but in the aspect of price/mA the AA battery is still the winner. Self discharge of a few years is acceptable for that type of battery.
      Another aspect i followed is, just to use buy-able and assembled modules, as i don't have enough time to build my own arduino board, or battery management (step up), etc. .....

      The core of the sensor is the battery itself. The components are mounted around the battery. The sensor can be completely disassembled in a few seconds, as the modules are just connected with pin headers.
      The power consumption for sleep is around 90µA, if i can believe my Fluke 175. The power consumption of normal operation and transmit i don't post here, because of two reasons:

      1. I was not able to get a good measurement result with a multimeter. I should integrate the consumption over time to get a real result.
      2. The lifetime of a sensor is dominated by the sleep consumption, not by the operating consumption (if transmission time is just a few times per hour)

      There are still some improvements to do, but ehh, this is just a prototype.

      Used components:
      -Arduino pro mini 3.3V @ 8Mhz (mcu board)
      -NRF24L01 (wireless board)
      -3.3V StepUp (0.8V-3.3V from Canton electronic an ebay product link)

      Modifications:
      -Arduino board: Cut LED
      -Arduino board: Cut LDO
      -StepUp board: Cut LED

      Physical dimensions (without pin headers):
      65mm x 22mm x 25mm

      Which values the sensor can send?
      In general this is just a battery monitor, as i want to get some experience of power consumption, but the pin header is able to work with various types of sensors. I use a simple DS18B20 temperature sensor on the header pins.

      Here are some pictures:

      Overall view1
      upload-55448569-77ab-4346-80ce-0fbb859991ea

      Overall view2
      upload-47cc27d8-c72c-47f6-8219-ed2668202c61

      Overall view3
      upload-ec04de50-8172-4891-914f-413dafa86824

      Overall view4
      upload-10334a15-91fb-4171-bda9-92e976e95de7

      Unused space over battery, but i didn't had the correct pin headers at home "mea culpa"
      upload-3e47d133-e3e2-46e0-8fc1-c3d667439ece

      Disassembled view1
      upload-fce77d46-7b45-4388-920d-f74055c0a75e

      Disassembled view2
      upload-6278a2b6-a1ce-41a1-a788-146209c0ab04

      Assemble view1
      upload-aba7428f-b2b4-40c3-a727-c4923e15f347

      Assemble view2
      upload-46644d8c-9537-431b-8bc2-eeaace130e79

      Assemble view3
      upload-2dd25b83-45e6-4861-9934-9fb3288185ef

      Assemble view4
      upload-d954cb15-453d-4817-bc0c-cb589acdf69d

      Assemble view5
      upload-ea78b989-eeb8-4d9d-be4d-846bf6b3e8d1

      Bottom view (remember - just a prototype)
      upload-62b434cd-c8d5-48dd-b959-d897f8de4224

      I hope i could give you some potential ideas for your own project.
      Questions, suggestions, feedback, all is welcome.

      posted in My Project
      klim
      klim