This project was inspired by a random funny video online of someone showing a device which monitors a plant’s humidity level, and if it got too low it started “screaming” with goofy prerecorded messages. I decided to do my own take of this project, and am in the process of building a similar device.

Requirements

  • Rechargeable, via USB-C
  • Capacitive moisture sensor
  • Nice big speaker on the front
  • Motion activated, so it doesn’t scream when nobody is nearby
  • All contained in a well designed 3D-printed case

Parts selection

Name Value/type Price QTY Link
Moisture sensor Capacitive 1.20 EUR 1 AliExpress link
PIR motion sensor SR602 1.06 EUR 1 AliExpress link
MP3 player module DFPlayer 5.03 EUR 1 DFRobot link
MicroSD Card 16 GB (any size will do) 1.64 EUR 1 AliExpress link
Arduino pro mini Or nano for built-in USB varies 1 NL supplier
18650 Li-ion battery INR18650-33V 1.89 EUR 1 NL supplier
18650 battery holder Wire mount version 1.50 EUR 1 NL supplier
USB-C breakout board Includes CC resistors 1.48 EUR 1 AliExpress link
LiPo / Li-ion battery charger TP4056 charging board with protection 2.00 EUR 1 NL supplier
Boost converter e.g. SX1308 varies 1 AliExpress link