Wireless Lightbar Controller v1.5

Filled under: Electronics

Date posted: August 1, 2008

Late 2008 – April 2010
Status: Retired

Wireless Lightbar Controller Transmitter and Receiver. v1.5


A wireless controller and receiver for interior lighting control applications geared towards RGB LED lighting.



To provide a custom designed wireless networking solution for an interior lighting system without the complexity and bulk of expensive commercial equipment.



Currently the electronics and the firmware in the initial prototype phase. The base station housing and the lightbar structure are still to be determined.


Network Topography:

The system employs a simple no ACK broadcast network servicing 100 individual RGB nodes (lightbars).


Base Station:

The base station is capable of controlling ten clusters with ten nodes per cluster for a total of 100 individual receivers(nodes).  The control structure is set up so each cluster has it’s own separate color changing mode and each of 10 nodes per cluster can be controlled individually within the mode.

There are several color changing routines(modes) programmed:

  • Solid – A single preset solid color.
  • Custom Color – User created color.
  • Rotate- Randomly changes solid colors.
  • Revolve – Slow fading throughout the various colors.
  • Flicker – Simulates a candle’s flicker.

Each mode can either set all nodes in the cluster to be synchronized or have each node it’s own independent color based on the mode sequence type.

Setup example: in a large house we can set up five rooms each with their own cluster with multiple nodes. So, the kitchen can have a soft purple hue, the bedroom set to warm red, the bathroom randomly rotates through solid colors, the hallway is cross fading smoothly at a welcoming pace, all while the living room speedily chases through the rainbow across the room’s several nodes.

There is an onboard EEPROM (electrically erasable programmable read-only memory) chip setup to store four full system settings for quick retrieval of custom displays.


Receivers (Nodes):

The receivers will be installed in each light fixture driving a single chain of RGB LEDs.

The hardware is a PIC16F631 providing three 8-bit software PWM channels to drive the RGB LEDs.  The circuit has several MOSFETs (not shown in the pictures) which allows for the expansion of the node to drive dozens of LEDs for maximum brightness. Each receiver can be user addressed to any cluster and to any of the cluster’s nodes via two buttons. The selected address is stored in the PICs internal EEPROM and is retrieved at power up.



Like my Lightbars v1 these light bars are designed to hang over doors and windows projecting lighting onto the walls and ceiling thus providing colorful ambient lighted to enhance mood and atmosphere. So far the plan is to design thin 6″ long PCBs to house RGB LEDs and their power resistors.


Wireless Technology:

The gem of this project is the Nordic made nRF24L01 2.4GHz 2Mbs transceiver with a simple SPI control interface.

The module used is manufactured from a small company called Decibit. Their modules follow the exact board specification set by Nordic which allows for maximum stability and range. The chip itself takes care of the wireless communication protocol such has packet forming, CRC, and ACK. The user just has to insure proper setup of the registers, payload information, control timing flow, and follow other specified procedures.



Base Station:

1x – Pic18F4515
1x – nRF24L01
1x – 128 * 64 GLCD
1x – 1k EEPROM
1x – 3.3v Voltage regulator
1x – 2n2222 NPN transistor
13x – Various resistors
1x – Variable resistor
3x – 0.1uF decoupling capacitors
10x – SPST off-(on) tactile buttons
x – Various connectors


1x – Pic16F631
1x – nRF24L01
1x – 3.3v Voltage regulator
1x – 2n2222 NPN transistor
13x – Various resistors
1x – Variable resistor
3x – 0.1uF decoupling capacitors
10x – SPST off-(on) tactile buttons
x – Various connectors




The Base Station

The Receiver Node


Here are the preliminary layouts for the PCBs.

Base Station preliminary PCB layout

Receiver node preliminary PCB layout


Below is current working version of code for the base station.


Below is current working version of code for the receiving nodes.



There are still many objectives to achieve and design features to work out. Once the bugs in the firmware are crushed and the prototype PCBs are fabricated it will time to move on to making the housing for the Base Station and the Lightbar structure.



November 2009

Well, it’s been many months, even almost a year, since I began this project. Not much to much to update really.

A slight problem came up with lost packets and slow data rates. So, I removed 5 of the ten clusters and tweaked the code from hard addressing to soft addressing which speeded up the transmitting cycle. Even 2 megabits per second can become slow with all the extra overhead. Lucky ACK is not required.

There has been some code additions such as a new color mode: candle. It simulates candle flicker at different dynamics with wind velocity changes.

I will be using prefabricated flexible RGB LED strips instead of fabricating my own PCBs with through-hole soldered 5mm LEDs. They are cheaper, thinner, and have lower power requirements.

Now since plans are in motion to furnish a wood working shop and to build a CNC router I will now have the capability to produce the wood housing for the control box and the wood for the bars. This is very exciting!

The PCBs are still are in the planing to be fabricated, just after adding a RTC (real time clock) to the controller and verifying it’s functionality.



April 2010


After running exhaustive tests on the range capabilities of the nRF24L01 communications module I decided it simply does not perform to my liking. The range indoors is less than 30 meters and going around around a wall drops it down to 10 meters! I believe it’s a limitation of the on board chip antenna. I reworked the whole system, changed to the MRF24J40MA wireless module, and fabricated prototype boards using my CNC router. =)