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TLC5940 PWM Driver

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Think of it like a shift register for Pulse Width Modulation (PWM).

The TLC5940 chip allows you to drive 16 Pulse Width Modulation PWM pins from 1 PWM and 4 control lines. Sort of like a serial-in, parallel out shift register , the TLC5940 gives 16 12-channel PWM outputs using only 5 lines on the microcontroller. We use these chips in our RGB flower necklace , to light up vibrant rainbow color around your sweetheart's clavicle . There is a for arduino. Another nice feature of these chips is they allow daisy-chaining. Want to see a tutorial about daisy-chaining TLC5940's? Let us know in the comments!

Images

4 TLC5940 modules

4 TLC5940 modules

4 TLC5940 modules being driven by an Arduino clone.
TLC5940 Nightlight Closeup

TLC5940 Nightlight Closeup
TLC5940 Nightlight 5

TLC5940 Nightlight 5
TLC5940 Nightlight 4

TLC5940 Nightlight 4
TLC5940 Nightlight 3

TLC5940 Nightlight 3
TLC5940 Nightlight 2

TLC5940 Nightlight 2
TLC5940 Modules Night light

TLC5940 Nightlight
Back of the TLC5940 Modules

PCB backside of the TLC5940 modules.
The TLC5940 chip

Here is a breakout board for TLC5940. It is daisy-chainable. It controls a LED bar graph.
Tree PCB powered by TLC5940

Tree PCB powered by TLC5940 with AAA battery pack.
Tree PCB powered by TLC5940 2

Tree PCB powered by TLC5940 with lithium batteries. Don't try this at home the lithium batteries don't have enough juice to power the LEDs for more than a couple minutes :(
QFN Close Up

The QFN package of this TLC5940 is cute, but pretty hard to solder.
Daisy Chaining

One tlc5940 plugs into another and all of sudden you have 32 12-channel PWM pins. Wowza!

4 TLC5940 modules being driven by an Arduino clone.

Video

TLC5940 Driver and Module Video

Video demonstrating 4 TLC5940 modules being driven by an Arduino clone. As the potentiometer spins the speed of the rainbow changes. The second part of the video shows the tree PCB with its 16 LEDs also powered by a TLC5940.

Code

This code uses the . It also uses our arduino color library available here. The code outputs a rainbow to five RGB LEDs hooked up to the TLC5940.

Download File

/* LucidTronix HSB RGB necklace * uses TLC5940 chip. for details see: * http://www.lucidtronix.com/tutorials/6 * Control rgb color by specifying * Hue saturation and brightness. * This code shows a rainbow. * It is okay to daiy-chain the chips * just change the NUM_TLCS constant * in the Tlc5940.h file. * This code uses an arduino color library * available here: * http://www.lucidtronix.com/tutorials/19 */#include "Tlc5940.h"#include "tlc_fades.h"#include "color.h"// how many millis to strobe over all the LEDsTLC_CHANNEL_TYPE channel;Color cur_color(1,1,1);int scope_period = (200 * NUM_TLCS);int led_period = scope_period / (NUM_TLCS * 16);float hue = 0;void setup(){  Tlc.init();}void loop(){  hue += 0.001;  if ( hue >=1 ) hue = 0;  float sat = 1.0;  float val = 0.5;  cur_color.convert_hcl_to_rgb(hue,sat,val);    uint32_t lastMillis = millis();  int cur_val = channel % 3;  int color_component = 0;  if ( cur_val == 0) color_component = cur_color.red*16;  else if  ( cur_val == 1) color_component = cur_color.green*16;  else if ( cur_val == 2) color_component = cur_color.blue*16;  tlc_addFade(channel,                      // led channel              color_component,   // start fade value (0-4095)              color_component,                            // end fade value (0-4095)              lastMillis + 2,               // start millis              lastMillis + (uint16_t)scope_period / 4  // end millis             );  if (channel++ == NUM_TLCS * 16) {    channel = 0;  }  uint32_t currentMillis;  do {    currentMillis = millis();    tlc_updateFades(currentMillis);  } while (currentMillis - lastMillis <= led_period);}

Parts

parts

Parts

Title	Description	#	Cost	Link	Picture
TLC5940	IC LED DRIVER PWM CONTROL 32-QFNValue:3 V ~ 5.5 V	1	$3.37	Link
ATMEGA168A-AU	IC MCU AVR 16K FLASH 32TQFPValue:1.8 V ~ 5.5 V 20MHz	1	$2.43	Link
Potentiometer	POT ROTARY, Linear 10K OHM 9MM SNAPINValue:10k	1	$0.76	Link
RGB LED	LED RGB SMD DIFF 4-PLCCValue:1.9V Red, 3V Green, 3V Blue	5	$0.55	Link
Switch	SWITCH SLIDE DPDT 6VDC 0.3A SMTValue:DPDT	1	$0.44	Link
LED SMD	LED 3X1.5MM 568NM Green Clear SMDValue:2.2V Green	16	$0.18	Link
Button 6mm Through Hole	Tactile Switch Through Hole SPST-NO 0.05A 12VValue:0.05A @ 12VDC	2	$0.1	Link