A VU meter circuit featuring USB-controlled PWM RGB LED employs three TLC5940 ICs and a PIC18F2550 microcontroller. This setup incorporates a total of 16 5mm RGB LEDs. I possess the source codes for both the computer software (developed in Visual Studio C#) and the microcontroller software (using Microchip PIC C).
The USB control software is compatible with Windows 7 and Vista (not supported by Windows XP). Furthermore, the circuit has been meticulously designed, including an express PCB schematic and associated printed circuit files.
This undertaking involves the development of a USB-controlled RGB LED VU Meter, designed to be compatible with Windows 7 and Vista computers. This project serves a dual purpose: Firstly, it demonstrates the process of extracting audio data from the computer and transmitting it via USB using this specific device.
Secondly, it functions as an open-source driver software for TLC5940. Although there exists a library for the TLC5940 AVR microcontroller, I have not come across an open-source library designed for PIC microcontrollers. Hopefully, this project will prove valuable to those seeking to manage numerous LEDs with PWM-based brightness control.
The software is coded using Visual Studio C# 2010 and operates seamlessly on both Windows 7 and Vista. However, it is worth noting that it is not compatible with Windows XP due to its reliance on the fundamental audio API.
PIC18F2550 RGB LED Vu meter diagram;
The TLC5940 functions as a LED driver with 16 channels, each of which offers individual adjustment capabilities for grayscale PWM brightness control, offering a range of 4096 steps, as well as a 64-step constant-current sink for dot correction. The dot correction plays a crucial role in harmonizing brightness levels across various LED channels and other LED drivers. This dot correction data is stored in an integrated EEPROM. Both grayscale control and dot correction can be accessed through a serial interface. The maximum current value for all 16 channels is determined by a single external resistor. Additionally, the TLC5940 incorporates two error information circuits.
- 16 Channels
- 12-bit (4096 Steps) Grayscale PWM Control
- Dot Correction
- Drive Capability (Constant-Current Sink)
- • LED Power Supply Voltage up to 17 V
- VCC = 3 V to 5.5 V
- Serial Data Interface
- Controlled In-Rush Current
- 30 MHz Data Transfer Rate
- CMOS Level I/O
- Error Information
- Monocolor, Multicolor, Full-Color LED Displays
- LED Signboards
- Display Backlighting
- General, High-Current LED Drive