http://picprojects.org.uk/projects/rgb/index.htm



RGB LED Mood Light
Standalone PWM
controller for RGB LEDs
using 12F6xx PIC

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  Circuit Description
  
• 
  Schematic & PCB artwork
  
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  Kit contents
  
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  Construction & PCB
  
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  Power Supply Requirements
  
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  Mood Light Example
  
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  Operation
  
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  Firmware download
  
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  Sequence Data file format
  
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This RGB LED Moodlight is new for Autumn 2010
Check back regularly for updates to this project page
This project is an update to the original RGB LED PWM Driver. The new version allows the use of either 5mm LEDs or the square bodied Superflux / Piranah style LEDs. The circuit now uses bipolar transistors rather than MOSFETs which make it more suitable for novice constructors and for the first time this project is available as a kit with all parts required to assemble the PCB including the superflux LEDs. (power supply not included) Full schematic and construction details are shown on this page, as well as the firmware download for those who want to create their own effects or build their own version from the schematic. If you're not into programming the kit includes a PIC microcontroller pre-programmed with the firmware and a number of mood lighting effects.






Circuit Description The circuit itself is fairly straightforward. Diode D1 provides reverse polarity protection for the board in case the power supply is connected backwards. C1/C2 and IC2 take the incoming 12 volt supply and provide a regulated 5 volt supply required by the PIC microcontroller. Thered, green and blue LEDs are arranged in three parallel strings ofthree LEDs. Resistors R1, 2 and 3 limit the current through the LEDsto a safe value when using a 12 volt power supply. The low side of eachLED string connects to a BC547 NPN transistor which is used to switchthe LEDs on and off. These transistors are in turn controlled by thePIC microcontroller which drives each of the red, green and bluechannel transistors with a PWM signal to control the average brightnessof the LEDs. Switch S1 is used to select different effect sequences. The firmware program running on the PIC microcontroller is the smartpart of the circuit and determines what colours are generated and howthey fade from one colour to the next. The three colours of LEDs are positioned on the PCB in an irregular arrangement to improve the colour mixing effect when placed behind / inside a diffuser such as a frosted glass globe. The controller uses (RGB) Red, Green and Blue high brightness LEDs that are pulse width modulated (PWM) to vary the intensity of each colour LED. This allows effectively any colour to be generated with rapid changing strobe effects, fast and slow colour fades as well as static colours. The data used to set and change the colours is held in an easy to edit file so if you don't like the sequences provided with it, you can modify the sequence data include file yourself and reprogram with your own sequences. (you will need a PIC programmer and some practical knowledge of microcontrollers and programming if you want to do this.)





Schematic <blockquote> [url=http://picprojects.org.uk/projects/rgb/schematic RGB101D.jpg] [/url] [url=http://picprojects.org.uk/projects/rgb/RGB LED Driver 101D sch.pdf]Download schematic as PDF [/url]

Artwork bottom	Artwork top	Overlay
The dimensions of the PCB are 50mm x 50mm. The PCB supplied with the kit is professionally manufactured thru-plated with solder mask top and bottom and screen print overlay on FR4 laminate with RoHS finish. If you want to etch your own PCB you can use the artwork above. Unless you are able to thru-plate your own PCB you will need to solder component leads top and bottom where required. Also look for the single via on the board that will need to be wired through. The ready made PCB supplied in the kit has through plated holes so this does not apply.

</blockquote> Kit Contents <blockquote>

	The kit available from the Picprojects On-line store contains all the parts required to build the RGB LED Moodlight. This includes all the components, quality FR4 double sided PCB, Superflux LEDs and a PIC12F629 microcontroller pre-programmed with the firmware. 12 volt power supply is not included in the kit
	A 2.1mm chassis mount DC power jack and 100mm of red/black wire are available as an option
<table id="table12" width="80%" border="0" cellpadding="9" cellspacing="0"> <tr> <td bgcolor="#00ff00"> Available now from the on-line store - self-assembly kit for the RGB LED Mood Light project only £9.99</td> </tr> </table>

</blockquote> Construction & PCB <blockquote> The information in this section is relevant whether you are assembling from the kit or sourcing everything yourself so please take the time to read through this section and refer back during assembly. This section is written so that even someone with little knowledge of electronics can successfully assemble the board; for those with more experience there is still useful and relevant information so please stick with it. </blockquote> Power Supply Requirements <blockquote> The RGB LED Moodlight requires a 12 volt regulated DC power supply rated for 200mA or higher. This is important, a non-regulated 12 volt supply may actually output 14 or 15 volts and this will damage the LEDs over time unless you alter the current limiting resistors. The power supply must also output DC not AC. Avoid halogen down light transformers unless they are specifically designed for operation with LED lighting since many supply unfiltered DC or even AC which is unsuitable. Also don't use Constant Current power supplies designed for LED lighting with this board. Many downlight transformers will not work correctly without a high power load connected to them. (Halogen type down lights use 20-50watts, the LED mood light uses about 1 watt) You can get plug top style power supplies from many places including eBay where there are good deals to be had. In the UK you can also get them from the high street retailer Maplin Electronics and online from Rapid Electronics If you're buying a power supply to use with the DC power jack option available from the on-line store, the barrel connector on the power supply needs to be 2.1mm (this refers to the diameter of the hole in the middle) Any of the following power supplies from Rapid Electronics are suitable and if you look at these it will give you an idea of what you need if you're sourcing from elsewhere.

• 5W Switch mode plugtop PSU Euro Plug 12V 420MA Rapid Part # 85-3732
  
• Plug & Go 12vdc 6 watt (EUP) Rapid Part # 85-3703
  
• 12vdc 1amp CCTV Smpsu (EUP) Rapid Part # 85-3770
  
• 12vdc 15watt UK Smpsu 2.1 C ve (EUP) Rapid Part # 85-3737
  

<blockquote> Part numbers correct as at September 2010 </blockquote> To summarise then, you need a 12 volt DC regulated power supply capable of delivering at least 200mA of output current (a higher current rating is fine, but it must be 12 volts DC) </blockquote> Mood Light Example <blockquote> This is something I put together in the workshop in 30 minutes, I'm sure you can do better but this gives you an idea of what you can do. This was made using a lamp bought from B&Q in the UK, type Athens Small Glass Table Lamp White. The base plate is made from 1mm aluminium sheet cut and shaped as shown. Holes are drilled for the PCB mounting spacers and the DC jack socket. The aluminium is bent and then 4No 10mm nylon hex spacers are fitted with 4mm M3 counter sunk machine screws. The DC socket is fitted to the angled bracket (note the use of insulating sleeving on the terminals). The assembled LED Mood Light PCB is then fitted to the base using 6mm M3 machine screws. The lamp bowl already had a slot in the side so when it is placed over the Mood Light assembly the power cable has room to pass through. </blockquote>
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google_protectAndRun("ads_core.google_render_ad", google_handleError, google_render_ad); Operation <blockquote>

• When the PIC is first powered on after programming, it should start running the first RGB sequence found. If you're using the original sequences supplied with the code here it will run a sequence of fading red thru blue thru green repeating.
  
  
• [url=http://picprojects.org.uk/projects/rgb/RGB101 effects.pdf]List of sequences / effects with the pre-programmed PIC [/url]
  
  
• User control of the RGB Driver is done using the S1 switch which performs multiple functions as described in the following section.
  
  Single press to Hold / Run current sequence
  You can press S1 at any time to stop the sequence running and hold the colour being displayed at that moment in time. Pressing S1 again will start the sequence running.
  
  If the controller is powered off while in the hold state when it is next powered on it will remain in the hold state displaying the same colour.
  
  Double press to Select Next Sequence
  (press S1 twice less than 0.5 second apart; think 'double-click' computer mouse button)
  
  Step through all available sequences. When the last sequence has been reached it will go back to the first available sequence. Each time the S1 switch is 'double clicked' the RGB LED PWM values are set back to 0 (LEDs off) and the new sequence will start running.
  
  When stepping through the sequences it always starts each new sequence in the Run state, even if it was previously in a Hold state
  
  ( the last sequences is indicated by 3 short blinks of the blue and green LEDs repeating)
  
  Press and hold to enter / exit sleep state
  Press and hold S1 switch for about 1.2 seconds to put the PIC into sleep mode. Once in sleep mode, press the S1 switch for about 2 seconds then release it to wake the PIC from sleep. If the S1 button isn't held for two seconds the PIC returns to sleep
  
  
• About 10 seconds after the S1 switch is last pressed the currently selected sequence number, RGB colour values and Hold state are saved to non-volatile EEPROM memory. When the RGB LED driver is next powered on, the saved sequence number is read back and will automatically start running the sequence. If it was in a Hold state at power off it will power on and remain in the 'Hold' state until S1 is pressed again.
  
  
• Anytime the PIC is put into sleep mode by holding S1 switch down, the currently selected sequence, displayed colour and Hold state will be saved to EEPROM.
  

</blockquote> Firmware <blockquote> The HEX file is ready to program directly into a PIC 12F629. The zip file contains the source code which you can modify or just view to see how it works. If you are going to modify the code I recommend you download and install the Microchip MPLAB IDE which will allow you to edit, modify and program the PIC seamlessly.

Description	Filename	Download link
Source code	rgb101g3.zip, v3.0.3, 14/09/2010	download
HEX file ready to program into the PIC	rgb101g3_main.HEX, v3.0.3, 14/10/2010	download checksum 0xDC5F

If you need a PIC Programmer I strongly recommend the Microchip PICKit 2, this is available from suppliers world wide or direct from Microchip. It's reasonably cheap to buy and reliable. </blockquote>

Format of the Sequence Data <blockquote>
The data used by the application for the RGB sequences is held in the file 'sequenceData.inc' You can edit this file to add, remove or change the data provided. You must ensure that it follows the format described. In particular pay attention to the 'end of sequence' and 'end of all data' markers and also ensure that each line of sequence data contains five comma separated entries. (see screen dump below)

A really useful on-line utility for simulating the sequences can be found here:RGB LED Simulator
(thanks to Marek 'Marki' Podmaka for creating and sharing this simulator)


In the screen dump above note the 'end_of_sequence' markers circled in red and the 'end_of_all_data' marker circled in purple.
You must have at least one sequence present up to a maximum of 256 individual sequences, although you're likely to run out of available memory on the PIC before you reach this limit.

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  Each line of data starts with a 'dt' (data table) assembler directive.
  
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  All data is specified using decimal values.
  
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  Each data value must be separated by a comma
  
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  The sequence data on each line has five fields:
  
  
  1. 
     Fade Rate: speed the colours fade from the current values to the new values. Each step occurs at an interval of 5ms x Fade Rate.
     
     
     
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       Fade Rate value of 0 indicates the RGB values will be updated immediately without fading.
       
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       Fade Rate value must not be set to 255 except to indicate end of sequence. (see e. below)
       
       
  </li>
  

</li>
<li>
Hold Time: after fade completes, delay before moving to next line of data. Interval is 50mS x Hold Time

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  Hold Time value of 255 following a Fade Rate of 255 indicates end_of_all_sequence data.
  
  

</li><li>
Red PWM value. 0 = 0% (LED off) through to 255 = 100% (LED fully on)
</li><li>
Green PWM value. 0 = 0% (LED off) through to 255 = 100% (LED fully on)
</li><li>
Blue PWM value. 0 = 0% (LED off) through to 255 = 100% (LED fully on)

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  Typically changes in LED brightness are more noticeable between 0 and 128 than from 128 to 255.
  

</li>
<li>
End of the current sequence data is indicated by the Fade Rate field being set to '255'. When the application encounters this it restarts the sequence from the beginning.
</li><li>
At the end of all available sequence data both the Fade Rate and Hold Time fields must be set to '255'
</li>
After editing sequenceData.inc the file should be saved and the rgb101g3_main.asm reassembled. The resulting rgb101g3_main.hex file can them be programmed into the PIC </blockquote> Contact us:

PCB artwork available on this site is free for educational or individual use but not commercial use. It is not permissible to use PCB artwork available on this site in any profit making venture, whether private, educational or commercial. Use of the free application program code or hardware presented on this website is not permitted in commercial products, or in any profit making activities. Disclaimer All firmware supplied either in a pre-programmed device or as a download, and any other information, hardware or software is provided on an "as-is" basis without warranty of any kind and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall Picprojects be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or otherwise) arising in any way out of the use of this firmware, hardware, software or information, even if Picprojects has been advised by user of the possibility of such potential loss or damage. The user agrees to hold Picprojects harmless from and against any and all claims, losses, liabilities and expenses.
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