🌵 Indoor WiFi-connected temperature and humidity sensor 🍶

power LiPO
wireless WiFi
sensor Humidity
mcu ESP8266
battery life 1 month
bom items 36
bom cost USD $26.92
vendors 5
completed May 2019


Prototype Front
Prototype Back
Prototype Side
Prototype Top

Getting Started

Step 1

Setup an IFTTT webhook to receive a POST request with data and add a row to a Google Spreadsheet.


Step 2

Connect to the WiFi access point Cactus {UNIQUE_MAC_ADDRESS}.

Go to the web page http://cactus.local to fill in the WiFi credentials and IFTTT webhook key.

Access point Webpage form

Step 3

Press on-board button or wait for the Google Sheet to update with a new row with a periodic update to the cloud.

Google sheets


  • ⚠️ USB Connectors on WeMos D1 Mini vs WeMos battery shield
    • Do not plug in the USB cable on WeMos D1 Mini while the battery shield is on the PCB
    • Flashing firmware: Remove the battery shield from the PCB and use the USB cable on the WeMos D1 mini
  • Charge the LiPo by plugging in the USB cable into the battery shield