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Multi Colour Led controller with Arduino Nano and G-ASH03 board.


By Fred Jansen & Peter Giling


Th G-ASH03 board unit an Arduino nano on board can be used for various applications.
Originally designed for controlling 12 servomotors via DCC or Motorola commands,
Here we have a very nice task for this board as well.
The multicour intelligent leds are available in wide setup ups like bars, LED strips, 64 LED boards etc.
To control these LEDs with integrated chip, it takes at least an Arduino nano, but it enables you to control all kinds of colours in each led separately, using only three wires.

Fred Jansen created firmware for the Arduino to control these LEDs via the Rocrail Dumper library.
Control is established via a controller setup in Rocrail, using "dumper".
Basicly, all you need is an Arduino Uno or Nano board and a sufficient supply of 5 Volt.
Also the G-ASH03 board gives you a very nice start with the multicolour LED adventure.
Rocrail, starting ad version 15816, is ready for it!


See G-ASH03


(Fred Jansen)

will be published after final approval



LEDii Firmware

Alternative firmware by Rocrail.


  • Max. 64 LEDs on connector 1.
  • Weather compatible.
  • Color outputs with dimming and blinking.
  • Range addressing to control multiple LEDs with one output.
  • Simple 3 aspect signal support.


Rocrail Setup

  1. Serial port of the Arduino Nano, 9600bps and no CTS

The firmware date, yyyyMMdd, is shown in the Rocrail trace after connecting to the Nano:

info: LEDii 20190821 (c)Rocrail


  1. LED number: Port
  2. LED range: Address-Port (Where by address should be less then port.)
  3. The Interface → Color option must be set
  4. Brightness is set by Interface → Value
  5. Dimming step is set by Interface → Delay (0…15) (A value of zero deactivate dimming.)
  6. The Interface → Blink option may be used to flash the LED
  7. The LED color is set by Color → RGB


  1. LED number: Port
  2. Port type: LED
  3. Control type: Aspect number
  4. Brightness

Supply G-ASH03

G-Ash03 by itself does not need much power, but the leds ar drawing plm 50mAmp EACH when lit full intensity. This makes the need for a good power suplly.
G-ASH03 is equipped with two voltage regulators, originally the same L7805.
But for the leds we need more, so for VR2 we use a HW-613 power supply, wich fits at the same place,
and can deliver 5V by 3Amp., where the power to the G-ASH03 can be max 24V dc OR 18V ac.
Supplying the Ledsstrips externally with 5V is also optionable..
If you need advice, please ask Peter

Connections G-ASH03 to LEDstrip

Ledstrip is connected to servo1 connector in the following way.

G-ASH03 servo1,2,3 ledstrip wire
re RED +5V
or GREEN signal

Different types of Ledstrips

So far, the program controls three different types of led strips:

  • WS2812B
  • WS2812
  • TM1803

The correct type needs to be selected via a special command to the Arduino Nano.
Please refer to the command manual provided below.

5V supply for ledstrip(s)

The leds on these strips can consume max 20 mA EACh.
This depends partly on the intensdity to be used.
With 60 leds in one strip the total curent will be 60 x 3 x 0,015 = approx 1 Amp for each colour.
Practicaly, the G-ASH03 can handle one strip 0f 60 leds.
With a supply ogf 24 V a total current of 0,5 Amp is needed for 60 leds.
In case of higher amount of leds, extra power suplly is needed.
GCA will come with highr current systems in due time.

2803-led-en.txt · Last modified: 2019/08/22 14:06 by rjversluis