Introduction: 24 Channel USB Connected LED Controller, Upto 1A Per Channel

About: Designing electronic creations from microcontrollers, LEDs and anything else I can pull out of a dumpster and make use of. Check my Profile

This device is designed to be a versatile high-current LED controller, with the ability to sink or/and source currents up to 1A per channel with dissipation of up to 2.5w per channel. The various jumpers and transistor placement allow the device to control many different types of LED configurations with LED voltages of up to 36v.

Easily controls 5mm , 1w, 3w, 3w RGB, 5w RGB, 12v RGB LED lightstrip, 12v solid color light strip, common anode RGB LEDs, common cathode RGB LEDs. Any combination of LEDs in parallel/series. Whatever kind/wattage/configuration can be made to work, to a max of 1A per channel or 2.5w dissipation.

A PIC18F4550 controls 24 high-current darlington transistors. The PIC is ready for USB communication and using Microchip's Library there is a multitude of USB connected devices can be made. From a simple emulated serial port, keyboard, mouse, HID, MIDI Devices, Audio Devices, and more. The available premium firmware allows the device to interact with the ColorMotion computer software, to create and upload patterns and settings to the device.

There are 4 pins left to use for other purposes, such as AdC, more transistors/mosfets, shift register whatever is needed. Accessed via the 6-pin polarized header, which can be used to connect to RA0, RA1, RA2, RA3, V+ and V-.ase. It accepts data from a PC/MAC/Linux over emulated serial port to the circuit board which outputs 8-bit PWM for all 24 outputs.

There are kits available in the Chromation Systems Store and all the files to recreate this project is in the ZIP file below.

Previous Version Assembly Instructions, Datasheet, Updates and More Info Can Be on the Main Website

The zip includes PCB diagram, Schematic Layout, and drill files. It is a single sided version of this circuit, so it is very DIY PCB friendly.

The 48 Channel Mono / 16 Channel RGB LED Controller, which is also USB connected, and is made for lower current LEDs is now available. 

Step 1: Supplies

Electronics: Purchase a Kit from The Store or Purchase a PIC or PCB separate.
  • 18F4550, DIP Buy One
  • Circuit Board, v.3  Buy One
  • 24x MPSW45AG Darlington Transistors or similar
  • USB Type-B jack, board mount
  • 20 mhz, version 3 can use any type, v1 & v2 require a series oscillator
  • 10kohm 1/4w resistor
  • 24x 1k ohm 1/6w resistor, value may vary depending on transistor
  • 220nF disc capacitor, VUSB
  • 2x 0.1uf disc capacitor
  • 2x 1uF electrolytic capacitor
  • 2x 22 pF disc capacitor
  • 5 pin ICSP header, optional
  • 6x 4-position screw down terminal blocks
  • 2-pin header, KK6410, use is optional
  • 2-pin housing, KK6471, use is optional
  • 6-pin header, KK6410, use is optional
  • 6-pin housing, KK6471, use is optional
  • 8 wire crimps for housings
  • 7805, 5v regulator, optional, can't be used in most cases
  • Button assembly parts: Momentary Push button, perfboard, ribbon cable, and 10kohm resistor
  • Soldering Iron
  • Diagonal Cutters
  • Wire Strippers
  • Flat screw driver for terminals
  • Multi meter
Other: Not included with the kit
  • USB Type A to Type B cable
  • LEDs or LED Strip, Find Some In The Store
  • Resistors for the LEDs
For controlling lower current LEDs over USB, please view 48 Channel Mono / 16 Channel RGB LED Controller

Step 2: Resistors

  • Start with the transistor base resistors, R1-R4 are all 1k ohm(Brown - Black - Red)
  • R25 is a 10k ohm (Brown - Black - Orange) pull-up for MCLR
  • R26 and R27 are 22 ohm (Red - Red - Black) for the USB Data lines, these must be crossed on version 3 PCBs, one on the top side, and one on the bottom side of the PCB. See Images.

Step 3: Select Jumpers

This board features jumpers to select if the transistors will be sinking or sourcing current. The board's transistors are laid out with 16 on one side and 8 on the other. Each side can be set to sink or source voltage based on the SEL jumpers and the position of the transistors. SELx to NEGx for sink, SELx to POSx for source.

Set all transistors to sink:
  • SEL1 to NEG1
  • SEL2 to NEG2
  • SEL3 to NEG3
  • SEL4 to NEG4
  • SEL5 to NEG5
  • SEL6 to NEG6

Set all transistors source:
  • SEL1 to POS1
  • SEL2 to POS2
  • SEL3 to POS3
  • SEL4 to POS4
  • SEL5 to POS5
  • SEL6 to POS6
Set 16(Output1-16) to Sink and 8(Output 17-24) to Source
  • SEL1 to NEG1
  • SEL2 to POS2
  • SEL3 to POS3
  • SEL4 to POS4
  • SEL5 to NEG5
  • SEL6 to NEG6
See datasheet for more jumper selections.

*Note that each side has 3 selection points, so if it was needed, the main trace could be cut at any point and transistors on the same side could be mixed sink/source.

Step 4: Oscillator, Disc Capacitors

  • Oscillator, OSC position, goes in either way

Disc Capacitors:
  • C1 - 220nF, labeled 224M, goes in either way
  • C2 & C3 are installed later, leave them out for now.
  • C4 & C5 - 0.1uF, labeled 104, go in either way
  • C6 & C7 - 22 pF, labeled 224, goes in either way
  • Line the notch on the end of the socket up with the notch in the top-side drawing.
  • Carefully line up the pins with the holes on one row of the socket then hinge it down into the adjacent row of holes.
  • Check to make sure all the pins are lined up, then press it in firmly.

Step 5: Transistors

*For transistors that are sinking current, the transistors are placed as seen on the top-side illustration. Transistor Pin 1(Collector) goes to hole labeled 1, Transistor Pin 2(Base) goes to hole 2, Transistor Pin 3(Emitter) goes to hole 3.

*For transistors that are sourcing current. The transistors are placed opposite of the top-side illustration. Transistor Pin 1(Collector) goes to hole labeled 3, Transistor Pin 2(Base) goes to hole 2, Transistor Pin 3(Emitter) goes to hole 1.
  • Start by taking a transistor and a needled nose pliers.
  • Figure out what way the transistor's center pin(Base) needs to be bent. Depends on sink/source configuration.
  • Grab the center pin with the needle nose pliers and bend it out a bit as seen in the images below.
  • Starting with T1, insert the transistor into its proper holes
  • Work your way around the board and solder in all 24 Transistors.

Step 6: Voltage Regulator & Electrolytics

7805 Voltage Regulator: A standard 7805, without a heatsink, cannot regulate the current that the device draws. If a 5 volt input is available the 7805 position must be jumped and soldered closed. For voltages greater than 5v the 7805 and a good sized heatsink can be used or a DC/DC Step Down Converter.

5v Input:
  • Connect the two outside holes with a length of 22ga solid strand wire, make sure it doesn't touch the middle solder pad.
  • Solder it on
  • Fill in the center hole with solder.
5v+ Input with 7805:
  • Install the 7805 as pictured.
  • Attach your heatsink with some heatsink paste.
Other Method: If you need assistance deciding or figuring out what to do, please Contact Us or PM.

Electrolytic Capacitors:
  • C2 & C3 are polarized and must be placed in correctly. The line going down the side indicates the negative lead, both the negative leads are facing inwards, towards each other.

Step 7: Terminal Blocks, USB Jack, & Headers

  • When installing the terminal blocks make sure the slot for the wire is facing outward.
  • The terminal blocks have connectors on the ends used to connect them together. Line up the tab with a notch in another one and slide them to attach. A string of 16 will be needed for one row, and 2 sets of 4 for the other.

USB Jack/Receptacle:
  • Only fits in one way, solder the case tabs first, make sure it is seated tight to the board and solder the 4 other pins.

  • Start by inserting the 5-pin ICSP Header into its position and soldering securly. This is used to reprogram the PIC, it is optional.
  • Insert the 6-pin polarized header, it can go in with the ramp inwards or outwards, if any other hardware will be connected make sure it will be compatible. This is used for external connections and interfacing, and is optional.
  • Insert the 2-pin Power Header, put it in what ever way will work best. Solder it in.
For attaching wires with the Headers and Housings, See This Webpage for details and instructions.

Step 8: Inputs/Additional Outputs

Headers and Housings:

Please See This Webpage for Instructions and Details on Using the Headers, Housings and Crimps to connect wires to the PCB.

RA0, RA1, RA2 and RA3 run directly to the PIC pins they can be used for switch inputs, AdC Input, or even for additional outputs, such as MOSFETs for multiplexing or a shift register.

The 6-pin header and housing can be used to attach an external circuit into the main controller. There are the 4 input/output pins in addition to +5v and GND.

Button Connection:
  1. There are 2 methods for connecting the button. Either solder the 10kohm resistor onto the bottom of the PCB, as seen in the images, and use a 2-strand wire to connect the button, mounted on the perf board, to the PCB, then hot glue the wire to the PCB so it doesn't break off.
  2. Follow the method below, which uses the 6-pin EXTHEADER to make the connection.
  • Center the momentary push button on the perforated board.
  • Bend the leads in the opposite directions
  • Position the 10kohm resistor so it can be attached to one of the button leads.
  • Strip the 3 strand ribbon cable
  • The ribbon cable connects RA3 to the unconnected button lead, +5v connects to a button lead and a lead of the 10kohm resistor, GND connects to the other unconnected lead of the 10kohm resistor.
  • Trim the ribbon cable to length.
  • Either solder the wires to the proper points on EXTHEADER or use the crimps and housing to connect the wires to the EXTHEADER header.
  • Optionally, Hot glue the wires down to the perforated board and a drop of hot glue where the button wires attach to the PCB.

Step 9: Final Testing

Look it Over for Errors:
  • Go over the parts layout and make sure all the parts are in their correct position.
  • Flip the board over and from the bottom, under good light, look over every solder joint. Look for solder bridges, dull solder joints, drips or any thing else that could cause a short or error.
  • If you are not using a 5v input voltage, apply voltage to the device, through your choice voltage regulator, and check around with a multimeter to ensure the device is getting the correct 5 volts.
  • Once any issues are found and fixed continue.

Install the PIC:
  • Find the dot on the top side of the PIC, that indicates Pin 1. Line the dot end up with the notch on the socket, line up all the pins in the socket, and press it in carefully. Watch for any pins that didn't line up as they could break off and wreck the PIC.

Power it Up:
  • Apply power to the device.
  • If you purchased a kit the PIC will come with firmware already flashed to it, so it should be ready to use.
  • Or if you are using a blank PIC, use the ICSP header to connect your programmer, it should detect the device and flash your firmware.
Test It:
  • Depending on your devices firmware, it may be ready to use now.
  • To test that the device is running, example ColorMotion Compatible, use a LED, resistor and some alligator clips to connect a LED to an Output(Connection depends on the LED and Controllers sink/source configuration) The LED should cycle or flash on and off, depending on what setting the device is playing.

Step 10: Firmware Options and Explanation

UPDATE: ColorMotion Version 2 is now available, please visit for more Information. Or utilize the Demostrantion HEX file found in the project files on Step 1.

Available in the ZIP file on Step 1 are a few different firmware options. The Full Featured ColorMotion Compatible Firmware must be purchased from the Store, but the demo version is included and has most of the same features, but has full Live Mode compatibility.

Project 2:

ColorMotion Version 1 Compatible Demo Firmware- 18f4550-ColorMotion-Demo-v1.hex
ColorMotion Version 2 Compatible Demo Firmware-18F4550-ColorMotion-FirmwareV2-rev-b-1.hex (recommended)

This firmware is a demonstration version. All features of the Full ColorMotion firmware work except for the uploading and saving of user created patterns and settings. Patterns can still be created and previewed(Demo Button) and will run till the device is powered down. Live communication from a computer to device is fully functional.

There are several patterns included in the Demo Firmware, they can not be changed. The full version of the firmware is available from the The Store.

Project 4:

MonoMotion Compatible Demo Firmware- 18F4550-MonoMotion-Demo-v1.hex 
- Link to Webpage
Similar to ColorMotion, but full of enhancements, additional features, more dynamic pattern storage, and ability to update to future versions, but is used to create patterns for single color LEDs. There are currently a few supported controllers and more will be added.

Processing Application - Live Mode Demo Software - Link to Webpage

The included application, including source code, can be found in the Project files on step 1. The program is used to demonstrate how to control a compatible ColorMotion device using Live Mode communication over USB. Using this software, colors can be selected on a computer and sent to the device to display. The color select options are Sliders, which select Black -> White -> Red -> Green -> Blue -> Purple, or there is an option to open a gradient image, then use the mouse to select the colors to display. There is a Color Cycle button which starts sending the device data that cycles it through all the colors. And lastly there are buttons, Settings Up and Settings Down, that can cycle through the patterns that have been uploaded to the device.

The code is well commented and can be used to create new compatible software or tweak to do what you require.

Project 1:

USB Communication, Old Processing Application - This is obsolete but still included.

Included is an application written in Processing, quite a simple language to learn, it is Java based, so works on most OS Platforms. Included is versions that should work on Windows, Linux and Mac.

It is just 24 sliders, that are labeled 0  - 100, position the sliders then press Spacebar to send the data to the circuit board. It converts the number to 0 - 255 and sends it to be used in the PWM routine. If more or less data bytes are sent, the data used in the PWM, will be out of alignment and the circuit will have to be reset.

Sliders are provided by the G4p library

Feel free to use any of my code for other projects, but please credit if it is released.

Firmware: 18F4550-24chanusb.hex

The firmware included here, written in C18, outputs 8-bit PWM to all 24 channels with the data sent from a Processing application. USB Communication is set up to go to the high interrupt and the simple PWM sequence is done in software in the main() function. But could easily be moved to an interrupt routine.

The project was originally in Microchip's Solutions library, under USB Device - CDC - Serial Emulator. So there are lots of comments and un-needed code still in it. The project already had setup files for the PICDEM USB board, which uses a 18F4550, so it was a matter of changing some lines of code and project setup.

In the Project folder I have included all the USB headers and Includes with in it, otherwise it expects them to be in the default folder, which gets confusing. So it should compile as is after changing the directories.(above)

Converting Microchip Solutions to work with the 24 Channel USB LED Controller, from Microchip's  Solutions Install folder: Any PICDEM Sample Code or Projects can be converted to work with this controller.

Open Project -> Build Options -> Project -> Directories

Add ../.. and ../../.. to Include & Library Search Path

Change include search paths to YourMicrochipDirectory\MCC18\h

Change Library search Path to YourMicrochipDirectory\MCC18\lib

Should compile then.

Converting Microchip solutions to work with the 24 Channel USB LED Controller from a different folder:

Open USB Device - CDC - Serial Emulator - C18 - PICDEM FSUSB.mcp

Open Project -> Build Options -> Project -> Directories

Add ../.. and ../../.. to Include & Library Search Path

Change include search paths to YourMicrochipDirectory\MCC18\h

Change Library search Path to YourMicrochipDirectory\MCC18\lib

Copy the USB folder from YourDirectory/Microchip/microchip solutions/microchip/include to your project directory.

Copy compiler.h from YourDirectory/Microchip/microchip solutions/microchip/include to your project directory.

on Hardware Profile - PICDEM USB.h comment out #define PROGRAMMABLE_WITH_USB_HID_BOOTLOADER

Step 11: Hooking Up LEDs

LED Types:
  • 12v RGB LED Light Strip, usually common anode based, set all outputs to sink, Colors go into the Outputs and the 12v+ is wired to voltage.
  • Single Color 12v LED Light Strip, Outputs set to sink or source, sink is preferred, wired from the voltage source to the output.
  • 5mm LEDs, outputs set to sink or source depending on needs. Each LED, or set of LEDs in series, are wired with a current limiting resistor in series.
  • 1w or 3w LED, outputs can be set to sink or source, with a properly rated resistor in series with the LED.
  • Other, there are other options of types and configurations, Contact Us or Send a PM with any questions.

Hooking the various configurations of LEDs up to to the circuit board is quite easy.

If a transistor is setup to sink current, the LED's cathode is connected to the terminal block.
And the LED's anode should then be hooked to the voltage source with a properly rated resistor in series.

Do not hook any LEDs up without a resistor in series with it, otherwise it will be destroyed as there is no onboard current regulation for the outputs.

When hooking up large amounts of high-current LEDs the select jumpers should be wired directly to the voltage input, so not as much current is ran through the PCB traces.

Step 12: Future Designs/Projects

This is a very versatile controller and could be used for many different projects, such as,
  • RGB Tube Light
  • Control LEDs from a computer
  • LED Multiplex controller
  • 3w or 1w LED array, PCB could do a 4x4 array directly, but a 8x16 LED Array with multiplexing
  • PC Case lights, as its USB connected, could even hook certain types of PC fans to an LED output, with some additional protection circuitry.
  • Cabinet Lights

There are kits for this and many other projects Available In The Store

The project files, including the files needed to make a PCB are on Step 1.

Thanks for reading and please check My Profile for more of my Projects and stay tuned for some great projects utilizing this circuit.

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