Evil Fruit Bowl - An April Fools' Project

Blog Postcircuito.io teamMon Nov 19 2018

April fool’s day is a chance for our team to get busy making silly pranks. The screaming fruit bowl got us all - even Luna our office dog. Here's a step by step tutorial, to make one on your own: Use with caution 😉

Electronics

The Main components you'll need for this project:

1. Arduino Pro-Mini 328 5v.

2. DF-Player Mini Mp3 Player - A very cool module. It has an on-board micro SD slot, so you can put mp3 tracks on it. Another great thing is that it connects to the MCU over software serial, for easy control, and with a simple command - dfplayer.play(track #) - you can play the tracks you want. Here’s a link to its product manual.

3. SparkFun HX711 - Load Cell Amplifier - make sure to use a load cell that can measure the total weight of the bowl and fruit. We started with a load cell that had a maximum weight of 2 kilos and that wasn't enough so we replaced it with a 10kg one. For best results, we recommend using more that one load cell.

Click this link or the diagram below to see the circuit diagram on circuito.io..

How does it work? The idea is simple - the load cell at the bottom of the bowl detects changes in its weight and triggers the DF player to play horrible sounds once fruit is taken out of the bowl.

Code

1. Download the test code from the "code" tab.

2. Make sure to extract the .zip file

3. Open the .firmware Arduino file.

4. Set the correct port and board (Arduino pro-mini, the default is usually Uno)

5. Connect the circuit to your computer and Upload the code.

6. Test your circuit by opening the serial monitor in the Arduino IDE and follow the instructions. If one the components isn't working, first check the wiring, and if it still doesn't work, go through our debugging steps.

7. When the circuit is working, replace the test code with the project code from the Github repo. Make sure to leave the //Include Libraries and //Pin Definitions at the top of the code, and also keep all the libraries from the original code.

Assembly

1. Place the bowl upside down.

2. Drill a niche in the bottom.

3. Turn the bowl around so that now it is facing upwards.

4. Find a nice piece of wood to cover the hole and screw it to the bowl.

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5. Place the electronics between the niche and the piece of wood covering it, like shown below