Скачать или смотреть 8 Channel Analog LED Light Organ

  / my_8_channel_led_light_organ  

This is an 8 Channel LED Light Organ that I built to amuse myself while listening to music. It is composed of 8 Sallen Key Bandpass Filters each set for different frequencies. The lowest on the far right, and the highest of the far left. 250 Hz, 550 Hz, 800 Hz, 1250 Hz, 2500 Hz, 5000 Hz, 6500 Hz, & 10000 Hz. I have a schematic created for this, as well as a PCB design. However the only thing that I do not have properly placed on either is the power and audio input. I need to go back and add barrel jacks and a 3.5 mm auxiliary port to my schematic. The only other thing that I plan to do to this device, is to add in two buffer op amps between the parallel filters and the aux port, in order to get rid of the annoying impedance that the speakers are adding to the circuit. It effects it enough that some of the incoming signal is damped a little bit.

Ok so how it works is, the incoming signal is feed into all of the 8 Sallen Key Bandpass filters at the same time. Each filter has a different range in which it will pick up a specific frequency. If that frequency is within that range or within the bandwidth, then depending on the amplitude of the signal the corresponding LED will light up. The Amplitude determines how bright the LED will get, as well as how close the signals frequency is to the center frequency. This is an analog device, so there is really no sample rate in which you need to calculate.

On a side note, I was able to reconstruct this device, using a 16-bit microprocessor, using Digital Signal Processing. I used the Goertzel's Algorithm somewhat using complex numbers in order to isolate the specific frequencies and output the result through general IO ports onto LED's. I did not do anything to set the brightness for stronger or weaker signals. It only looked for a frequency within the bandwidth and then turned on an LED. Lot of fun, and well frustration. I know, I am a nerd, but I enjoy what I do!