Cactus: Measure humidity in kitchen cupboards

Description

How much does the humidity decrease when we put a dehumidifier in our kitchen cupboards?

This project will use a WeMos module (ESP8266) to get the values of humidity and temperature from a Si7021 sensor and send it to IFTTT to log in a spreadsheet every 4 hours. It will be battery powered by a LiPo and even without any connectivity to WiFi, a button press will indicate the humidity level via a bar LED display.

Files

bill_of_materials.csv

Complete BOM with details on the manufacturer, cost, vendor, part number, etc

Comma-Separated Values - 2.57 kB - 05/13/2019 at 07:16

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schematic.pdf

KiCad schematic

Adobe Portable Document Format - 1.51 MB - 05/13/2019 at 07:16

Preview

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footprint.pdf

Footprint layout of the PCB

Adobe Portable Document Format - 318.70 kB - 05/13/2019 at 07:16

Preview

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Components

1 × WeMos ESP8266 module

1 × WeMos battery shield To power via a LiPo

1 × Si7021 Adafruit temperature and humidity breakout board

5 × Red SMD 0805 LEDs To display the humidity levels on-board when pressed a button

4 × M2 spacers

Project Logs

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Deployed: Week 2
sayanee • 05/14/2019 at 06:06 • 0 comments

For 1 week, the device has been pinging back to the cloud with average humidity value as well as the battery values as recorded in the Google sheets.
The humidity values were pretty consistent from 87 RH% to 92 RH%.
The LiPo battery voltage levels came down steadily from a fully charged value of 4.2V to 3.9V.
I just put in the dehumidifier beside the device. So let's see whether the humidity levels change at all.
Deloyed
sayanee • 05/13/2019 at 07:05 • 0 comments

Cactus is now finally deployed in the kitchen cupboard without any dehumidifier as a control. Every 4 hours it is pinging IFTTT with the humidity values as well as the LiPo battery voltage. Follow the live log in Google Sheets right here!
After a week, I will put in a dehumidifier to see whether the humidity levels are affected.
Mechanical considerations before designing the PCB
sayanee • 08/27/2017 at 22:56 • 0 comments
1. Place the PCB on top of the 2 AA battery holders
2. Connect the battery wires on one of the shorter edge of the PCB
3. Solder the ESP-12F on the other shorter edge of the PCB
4. Bar LEDs are lining up on the longer edge of the PCB
5. Place the ESP-12F module within the dimensions of the battery holder so that the final form can stand vertically as well