Project Overview
This project uses the ESP32C3 single-core micro to develop a wide range of animated light patterns on five faces of a cube, using DotStar RGB LEDs configured as small 8x8 panels. Built into this cube is a 3-axis motion sensor, a microphone and an ambient light sensor, so that it can respond to changes in it’s environment. The code I have provided contains a library of graphics functions, which can be combined in interesting ways to develop a wide range of lighting effects. The cube can also be used as a desk lamp and to provide mood lighting of any colour you choose.

Watch the video on the right to see how they perform, and an insight into the technologies mentioned above.

Using the 3 button switches at the base of the cube you can simply switch it ON or OFF, or select a specific pattern. The code stores your latest choice, so that it returns to that mode when it is switched ON again, or when power is resumed. Most of the patterns are animated in some way, mainly by sounds picked up via the microphone, or via the motion sensor.

Whilst we are driving 320 LEDs in this project, the data rate is high enough to support frame rates in excess of 30 fps, so good animation effects can be a achieved. You can also vary the frame rate dynamically, which in turn speeds up or slows down the animation.

The graphics library (Gfx) provided enables you to draw boxes and lines, copy side faces, rows and columns, rotate faces and even draw 8x8 characters at any point on a face, in any colour. And it is relatively easy to add more functions, depending on your C++ coding skills.

The code runs in multi-tasking modes, which enable it to respond to button switch presses and sensor readings, whilst driving the 320 RGB array. It uses the FastLED library for that.

The ambient light sensor enables the cube to be dimmed down in low light conditions, so that it does not appear to be too bright, just like an LED alarm clock.

The DC offset analogue signal from the microphone is sampled at a high rate, then subjected to filtering to remove the offset, make it unipolar, and apply squelch and peak detection functions.

The 3-axis motion sensor provides raw and filtered acceleration and gyroscopic rotation data. So the code can detect precise movements, and feed the data into animations.

The circuit diagram is shown here on the left, with the ESP32C3 micro connected to the microphone on the left, and the light and motion sensors at the top. The LED cube takes its power from the 5v feed, and is connected to the micro for the data. With these DotStar panels then appear to work well from a 3v3 logic output, so there is no need for a level-shifting LED, as in the larger panel.

The 3 button switches are connected to individual inputs, which are configured as pull-up resistors to reduce the component count. When you press a button switch the code in the micro produces a colour in the single LED built into the micro, as confirmation.

Note that LEDs are only 40% efficient, so at high brightness these panels consume a large current and they will heat up. If you wish to run them at high brightness levels, you should predict the current drawn, and limit the brightness in code, so as to avoid panel failure due to overheating.

All of the 3-D models are provided as STL files, zipped together into one compressed file. They can therefore be used with a slicing application of your choice, to create the G-code files for use with a 3-D printer. For my project I used PrusaSlicer, which is a free download from the internet, but there are many other free applications to choose from. I just think that PrusaSlicer is one of the best.

The cube is assembled from a single flat plate, that folds up to form the cube, once the 8x8 panels have been glued to it. Space is very limited in this design, so some components are glued into position, like the ESP32C3 micro; as sockets would impact on the depth of the case.

The cube is powered from an external DC wall adapter working at 5 volts. I chose a 3 Amp unit, which provides more than enough light from the LEDs, but for maximum brightness you would need a supply in the order of 10 Amps, and the cube would get very hot indeed.