LightshowOnTheGo

A DIY Car LED project designed to be responsive to music (and other potential inputs). This project will involve a series of versions that will focus on space optimization, interface methods (eg. Bluetooth, WiFi, JTAG, etc.) and I/O handling (eg. microphone, button/switch controls, etc.)

Lightshow Version 1.0

Below is a general outline of the project architecture. All files relating to V1.0 can be found in the Lightshow1.0 directory.

Hardware

Parts listing

• 1 LED Strip
• AVNET MicroZed FPGA (considering a Teensy 3.6 microcontroller as well
• A protoboard with the following components:
  • Transistors used for PWM of LEDs (p2n2222a transitor)
  • 4x1 male Molex pin headers for LED Strip
  • 3.5mm DC Power connector (see TODO)
  • 3x1 male or female socket pin header (FPGA/Microcontroller connector to transistors)
• 3 Resistors (100 Ohm) to limit current draw
• 12V Car power adapter with a 3.5 mm connector
• Wire (22 gauge)

Transistor/LED Circuit

• 12v power supply in series with a 100 Ohm resistor, p2n2222a transistor (input at collector) and ground connected to emitter.
• Zedboard interfaces with a common ground at the collector
• Gate is driven by a 3.3V signal from the Minized
• The above circuit yields a 50mA current draw. If we can get it to 1A we can get really bright LEDs which would be ideal.

Microphone

• Documentation:
  • MiniZed-HW-UG pdf
  • MP34DT05 Microphone Datasheet
• Output
  • Audio Clk
  • Dout
• The Dout signal alternates between the right and left channel every other clock cycle. Output is in pulse-density modulation (PDM)
• Clk Low = Left Channel
• The microphone is connected to some codec inside the FPGA
• Demodulate the signal by using a low pass filter... and try to figure out why this works.

TODO

• Estimate current draw on the LEDs given a 12V DC power source. 1A current draw
• Determine the max level of brightness desired from LED strip Max brightness at 1A
• Consider power draw of LED strips in parallel for future versions
• Create circuit diagram
• Create small PCB to interface 12V power cable to LED strip
• Add a switch to enable/disable pwm capabilities
• Select a transistor capable of meeting the following constraints:
  • Max current drawn by the LEDs
  • Can be driven by a 3.3V/2.7V/1.3V signal at the gate (voltage constrained by microcontroller/FPGA)
  • Does not overheat to unsafe levels
• Find suitable protoboard
• Verify wires are capable of current levels selected

Software

TODO

• Determine the sample rate of your microphone
• Figure out interrupt timing in relation to the sample rate
• Design lowpass filter to receive microphone input
• Design a filter to detect the base in a song