Our project is to make an interactive cube of LED.
We have a cube of 12x12x12 LED (45cm x 45cm), commanded through a stm32 which is in charge of the display. We add in the cube some sensors, we will detect the presence of the hands nearby wires added in the cube and detect the rotation of the cube thanks to a gyroscope. The stm32 is also in charge of collecting information on the sensors. We can communicate with this stm32 thanks to USB.
We have a beagleboard at the base of the cube, linked with the stm32. Here we can create animations or games using the two types of sensors and display it on the cube. What’s more we will add a Kinect connected on the beagleboard, we can reproduce an object in the cube, we can play games such as Rubik’s cube in the cube of LED through the Kinect.
We have chosen USB because if we want we can connect the stm32 directly to a computer or a mobile phone, and create a program on it to play with the cube.
Let’s concentrate a bit on our LED. We will have 1728 RGB LED, so 6912 wires to connect. It seems quite a lot to connect on a PCB, so we will use multiplexing. Our LED are with a common anode, on each floor we link all anodes, and on each columns we link all “red cathode” together, all “blue cathode” together and all “green cathode” together. So we will light one by one each 12 floors, quickly enough to see the whole image.
Talking about our PCB, we don’t want 444 wires to connect on the PCB so we want a huge PCB as big as the base of our cube and plant our cube in it. On it we only will have the drivers and the links between the base of each column and the driver, so we will make this PCB in the school with only one side (in reality we will make six more little PCB side by side). And for the rest of the electronic we will have a little, normal, PCB.
Here is our architecture: