The animal sounds off in its own voice when its animal puzzle piece its placed correctly.

For kids under 24 months. Your sons will eljoy when they hear all six sounds emitted by yhe animal.

This project it is based on a commercial product, but I wanted to make my own version for my daughter. And share with the community so you can make it for your sons too.

It reproduces the sound of the following animals:

Cow.
Horse.
Bird.
Dog.
Sheep.
Monkey.

Step 1: List of Materials

Arduino nano/uno/micro.
DfPlayer Mp3 module.
Speaker 8 ohms @1W.
Battery 9V.
Micro SD Card.
Wires
Pieces of animals made withexpanded polystyrene, wood or any material.

Step 2: Construction

Get pictures of animals or the theme you want. I got them on internet.
Print the images.
Paste them onto the expanded polystyrene (or your desired material) and with a cutter cut the shaped. pieces.
Make the same cuts in the expanded polystyrene layer so the inner part fits the animal piece.
Download mp3 files of animal sounds (or the theme you want) and store them into the micro SD card.

Place two wires or terminals into each inner piece. Cover each terminal with aluminum foil.

Later, place aluminium foil in each piece of the enough size so it can make full contact with the two terminals of the inner piece. As shown in the picture.

Step 3: Diagram and Operation

Buttons in the diagram must be replaced by wires.

As I mentioned in the previous step, each piece need two wires or terminals. One goes to the pin showed in the diagram according to the animal piece. For instance: sensor of the cow piece goes to the pin 2 of the arduino nano.

The other wire or terminal goes to the negative of the battery. Each wire of each piece is common.

A 1k ohm resister must be connected to the RX pin of the DfPlayer for reducing noise when playing.

Be careful connecting the 9V batter to the Vin pin of the arduino. Not to 5v pin.

The Vcc pin of the DfPlayer connect to 5V pin of the arduino.

The operation principle of the circuit is very simple.Pins 2 to 7 of the arduino are in high logic state. When a piece make contact with the terminals, the corresponding receives low logic. This change is detected by the arduino code and reproduces the MP3 file stored in the Micro Sd Card through the dfPlayer module.