Arduino led cubes serial#
Arduino led cubes software#
Arduino led cubes code#

This allows us to drive 64 channels or 64 outputs simultaneously so these are addressed as channel 0 - 63. In the library configuration file we specify that there are 4 TLC chips because there are 16 outputs per TLC chip. When addressing the TLC chips the available library provides an interfacing functionwhich allows us to talk to the channel on the TLC system.

Arduino led cubes code#

You need to look in the comments section of the source code provided to check what settings need to be changed in the TLC configuration file. One thing we have to be careful of when adjusting or compiling this code is the configuration of the TLC library. We need to blank the layer control for a very short time while we write the new values to the columns, and then we can switch to the layer above and remove that ghosting affect. As we scan the display faster, if we don't blank, we will a trailing of light through the layers where we don't actually want the light so the value of the previous layer will carry across onto the next one. This is what is connected to pin 7 of the arduino and is represented by the output value 128 because it is the most significant bit of a byte. By utilizing the d input for the d-multiplexer which exceeds the 3 - 8 specification, we can then blank all outputs of the d-multiplexer. When you increase the speed of this scanning there are a couple of problems you can run into which is why we need to incorporate blanking on the d-multiplexer. There is a preprogram delay which can be adjusted if need be which determines how long each layer is on for. On each loop of the program there is a nested loop which scans through the 3 dimensional array and writes one layer at a time. This gives us 512 bytes of storage and each byte represents 0 - 255 grey scale value which then gets converted into a pulse with modulated representation of intensity. Just focus on the 1 - 8 for each axis for now. The 0 address is used for manipulating row when we think about patterns and algorithms. It is an array with the dimensions of 0 - 8 in all directions but realistically only 1 - 8 are used for the current state of display. In reality, because of the structure of the code, the cycle time will vary so the image or the current state of the image is represented by a 3 dimensional byte array. If we can scan through them fast enough, (typically 20 - 25 cycles per second or 8 layers 25 times per second) then they will appear to all be on at the same time. This is so we can scan through all of the LEDs or layers of LEDs without necessarily having them all on at one time. Philosophy of Displaying the Image The display philosophy allows us to only light up one layer of LED lights at a time, so in order to view the entire cube of LEDs simultaniously, we rely on a phenomenon known as Persistance of Vision.

the patterns and algorithms used to generate the image.

the philosophy of displaying the image.

Arduino led cubes software#

The best way to think of the software is in two main parts:

Arduino led cubes serial#

The code is transferred to the arduino uno via a USB cable so this requires a USB to serial converter to program the AVR directly.

Software for the LED cube is written in C and compiled under the arduino development environment.

This library makes it easy for us to interface with this complex chip. There is a TLC chip library available from the arduino website which allows us to drive all this with minimal software coding. Within each PWM shield, there are two TLC chips - arranged in a daisy chain serial communication fashion. The column will source or supply the current via the positive anode to the LED and the common cathode layer will be sunk to ground using MOSFET. Using PMP transistors and sizing the current reference resistor on each PWM shield appropriately to compensate for transistor gain, we can provide a current source rahter than sync to each column. In order to do this, you need to assemble an interposing transistor board. However because of the way this cube has been wired, this chip has to interface with the positive or anode connection of each LED. The PWM shield is designed to sync current so to turn on an LED, the PWM shield expects to be connected to the negative or cathode connection of the LED. Using this idea we can light up an entire column.

To light up a particular LED, we switch on that column and that layer at the same time to pinpoint an LED. Each of these PWM shields provides up to 32 pulse modulated outputs so these are the brightness controls for 64 columns in total (2 shields with 32 LED controls each). Control electronics for Columns To the interfacing pins on the arduino uno brain, we connect two PWM shields which are cascaded together in a long chain.