Duplo brick with RGB LED and microcontroller

thingiverse

This is a Duplo brick (2x4, 2 high) with space for several features: - A 5mm LED; - A CR2032 holder of the "insert two stripped wires" sort; - A button switch (16mm diameter hole). In my case, I used an ATTiny85 microcontroller and made the LED an RGB LED. The button has two functions: - If you play a rhythm on the button, the LED will repeat the rhythm (flashing in your favourite colour); - If you long-press the button, you can select what is your favourite colour (it will cycle through hues, release when satisfied). My two-year-old loves this brick! I wrote this as a remix from topacsz' [Smart LEGO Duplo Brick](https://www.thingiverse.com/thing:3744833) but rewrote everything from scratch. The main differences are that this does not use a CR2032 holder (one is included in the model), and this uses a panel-mount switch. I used these components because they were available at the time, and I thought the bigger button would be easier to manipulate for a child's hand. There is still much room for improvement: - The microcontroller has one free pin which can be used for a tiny speaker (think headphone speaker); - The 5mm RGB LED could be replaced by a WS2812, which has a smaller footprint, uses fewer pins (only one instead of three), and could be attached inside the brick facing a thin part of the brick wall (lithophane-style). This would have been safer for the younger ones' eyes, and having a flat wall would have made the thing more resilient as well; - What to do with the two pins left available after this? Motors? Make this an alarm clock? - While I housed the microcontroller in a DIP8 socket (to be able to remove and reprogram), the real "pro" solution would have been to include an ISP header on the side of the brick. But then soldering all this inside the brick would have been a complete nightmare! Written in OpenSCAD. Printed in PLA (Arianeplast - French manufacturer) on an Ender 3.