Evil Fruit Bowl for April Fool’s Day

We really like April Fool’s day, we even made a contest especially for this day. But we never thought we’d be fooled by one of our own! We all fell for for it, even Luna, our office dog slash full-time mascot.

How does it work?

A loaded cell at the bottom of the fruit bowl weighs the fruit bowl. When it detects a decrease in weight (meaning fruit was taken out of the bowl) the Arduino triggers a DF player with a random track of horrible sounds. And there you have it, an evil fruit bowl.

Electronics

Here’s a magic link to circuito.io with all the components you’ll need: DF Player, Load Cell, Arduino Pro Mini and a 9v battery.

Click generate, and you'll reach our new reply!

Steps

Go through the 4 sections of the circuito.io reply:

• BoM - a list of all the components you’ll need including links to buy them.

• Wiring - Wire up the circuit as shown in the step-by-step guide.

• Code - Make sure to read the instructions carefully (download, extract, upload to Arduino).

• Test - **new section**! Follow the steps here to verify that you connected your components correctly.

• Upload the new code - When you’re done with the circuito.io reply, copy the code from this tutorial and replace it with the code in the original reply. Make sure that the pins are set according to the original reply (at the top of the firmware.ino tab) and you’re done with the electronics.

A bit more info about the electronics of this project

• Arduino Pro mini - small. Efficient.

• DF player and speaker - 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.

• Load cell\strain gauge + Amplifier - make sure to use a load cell that can measure the total weight of the bowl and fruit. In the beginning, we took a load cell that had a maximum weight of 2 kilos and that didn’t suffice. Eventually, we replaced it with a 10-kilo load cell. Crisis averted.

Note: We recommend putting more than one load cell for best results.

Lite Components

When selecting the components on circuito.io, you may have noticed that both the DF player and the Load Cell Amplifier have tags that say “unverified” and “no code”. This is because they were added as Lite Components. What are Lite Components you ask? These are components that we added to circuito.io but haven't tested them beforehand, and also haven't written or found code for them. However, they will appear in the wiring guide.

Assembly

• Place the bowl upside down.

• Drill a niche in the bottom.

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

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

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