You can now play MP3 files directly in CircuitPython with no dedicated decoding hardware! You'll be able to use this new capability in all sorts of projects, including this creepy Lars the Sloth voice box project!

The benefit of MP3 over other non-compressed file formats, such as WAV, has always been their small file size, meaning you can pack a lot of songs or samples into limited memory. However, decompressing those small files for playback was too taxing for older microcontrollers, so we had to use dedicated decoder chips at an additional cost, including licensing fees.

Thanks to the raw speed of M4, the days of requiring a dedicated MP3 audio decoder chip are behind us. And, since the patents have expired, we can now distribute MP3 playback libraries free of charge!


Angled shot of a Adafruit Feather M4 Express.
It's what you've been waiting for, the Feather M4 Express featuring ATSAMD51. This Feather is fast like a swift, smart like an owl, strong like a ox-bird (it's half ox,...
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Angled shot of a Adafruit Prop-Maker FeatherWing.
The Adafruit Feather series gives you lots of options for a small, portable, rechargeable microcontroller board. Perfect for fitting into your next prop build! This FeatherWing will...
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Mini Oval Speaker with pico blade connector
Hear the good news! This wee speaker is a great addition to any audio project where you need 8 ohm impedance and 1W or less of power. We particularly like...
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Slim Lithium Ion Polymer Battery 3.7v 400mAh with JST 2-PH connector and short cable
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This...
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Angled shot of a Tactile On/Off Switch with Leads.
Squeeze once to turn on, squeeze again to turn off! This clicky switch makes a great power switch or mode toggler. We like this switch because it's easy to embed in a seam for...
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Angled shot of a Micro B Round Panel Mount Extension Cable - 30cm.
If you need to add a panel-mount connection for USB Micro B,  but don't have the time or ability to cut a custom oval or square hole, this Round Panel Mount...
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Five pack of 20-pin 0.1 Female Header - Red plastic
Female header is like the duct tape of electronics. It's great for connecting things together, soldering to perf-boards, sockets for wires or break-away header, etc. We go through...
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Break-away 0.1 inch 36-pin strip male header - Red plastic
In this world nothing can be said to be certain, except we need headers, headers, and more headers!Each pack contains ten red 36-pin 0.1" pitch...
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Black Nylon Screw and Stand-off Set with M2.5 Threads, kit box
Totaling 380 pieces, this M2.5 Screw Set is a must-have for your workstation. You'll have enough screws, nuts, and hex standoffs to fuel your maker...
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Plush Doll

The choice is yours, but if you want to embed creepy, semi-threatening voice samples into a murder puppet, you could do worse than a Sickening Sloth Fuggler.

The teeth. Oh the teeth.

Who is Lars?

Lars is the sworn enemy of CVT Joseph, the ice cream truck godfather of Los Angeles, and owner of  CVT Soft Serve.

Lars is angry that Joe won't reveal the location of his Wonka-style Golden ice cream gift cards. This video linked below will make everything clear:

Actor Matt Biedel (Umbrella Academy, Narcos) has kindly given us permission to use Lars's voice. At least that's what Joe claims.

This project is not sponsored by CVT Soft Serve. John is is just really obsessed with Lars and great ice cream.



This guide was first published on May 27, 2020. It was last updated on Jul 13, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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