Posts Tagged ‘FFT’

Visualize Music with a Muscled FPGA

Tuesday, September 13th, 2016

Picture of LED Music Visualizer with Zybo Board

The Zybo Board is one of the most powerful tools in FPGA and this is because it is FPGA combined with an ARM processor that widens the spectrum of possibilities with FPGA. Today’s post is yet another dive into Zybo’s possibilities and in this project a visualization of audio signals or music will be accomplished. The author has been very detailed about this project and has explained every aspect of it in 18 steps.

The Hardware needed for carrying out this project are the Zybo Zynq 7000 FPGA board, a neo pixel LED matrix, a 5V 10 A power supply, a female DC power adapter, 3 pin male to male header, a 1mF capacitor, an audio splitter and some jumper wires. The connection diagram is provided by the author in step 17.

The code basically uses the principle of FFTs to detect frequency components in the audio file. Depending upon the magnitude of frequencies received, the LED display has been programmed to light up. 16 steps starting from opening Vivado to run the code to generating a bit file for the FPGA has been provided by the author. You can download a zip file which contains all modules relevant to the project. The author has used a combination of C, custom Verilog and HDL to code the project. This gives an ease in defining GPIO ports and makes the circuit a lot simpler.

Another interesting aspect is that the FPGA has been so coded that with the help of switches, your LED matrix can either act as a spectrogram or as a visualizer seen in media players.

Let me challenge you to achieve similar results adapting your own FPGA!

By jtdykstra

The Daredevil Cam is Closer to Those with this Info and a FPGA

Thursday, August 4th, 2016


Hello FPGA hobbyists! Ever wondered what it would be like to see sound? The author thveryat very same curiosity for close to 10 years, and kept a constant vigilance for ideas to build something that would help him materialize his dreams. The Daredevil camera, built using a bunch of MEMS microphones and a FPGA actually lets you see sound.
The author started the project wielding inspiration from the Duga RADAR. However, the scale of the project becomes huge and something beyond what hobbyists can afford. The author then tried a more practical but tedious and time consuming design approach which involved using an array of microphones. Each microphone in the array picks the sound relative to its position and displays it on screen, which will always be different from the next microphone because of the difference in position.
While the logic behind this is sound, implementing an array of microphones, each having a Pre-amp stage and then an ADC stage before feeding inputs to the FPGA is not practical. The cost and time put into the project becomes huge, and even then error margins can be significantly high.
This is the reason why the author used a set of MEMS microphones. MEMS microphones have an inbuilt Pre-amp and ADC stage, and thus the project collapses in complexity. All that is needed is an array of MEMS microphones and an FPGA board to implement the project. FPGAs are FFT friendly and this has a huge part in the project.
The author has shared the PCB design layout here. Besides this a number of fail safes such as spare patterns for a Flash chip, SOIC and DIP. He also used micro SD cards for each array to store the data and send it for processing to get an output of close to 30 frames per second. The FPGA, a great tool for pipelining is used to get his output.
The author then tried out the theory in an 8×8 array and arrived at the conclusions that the device is pretty sensitive as it even picks up sound way reflections from surfaces. But since anechoic chambers are impossible to build at home, he went on to build a 16×16 array.
While the results can be seen in this page, the author is yet to perfect his design. There are persistent issues with micro SD card since its storage algorithm conveniently cuts off data to compress data, which is essential for the FPGA to build a 30 Frame/sec output.
To be heard…or seen.


By Artem Litvinovich