Nested serial network configuration for array of serially connected light heads
An array ( 166, 184, 194, 230, 256 ) of multiple light heads ( 170, 186, 194, 236 ) for a vehicle ( 100 ) has a primary Controller Area Network (CAN) serial data bus ( 108, 224 ) to carry first serial communications among spaced-apart CAN nodes ( 112, 118, 130, 136, 140, 154, 220, 260, 288 ) communicatively coupled thereto. The first serial communications initiate a flash sequence from the array via second serial communications provided to the multiple light heads communicatively coupled to a nested CAN serial data bus ( 180, 190, 200, 238 ). An array controller ( 130, 136, 140, 220, 260 ) segregates the nested CAN serial data bus from the primary CAN serial data bus while providing a communications bridge between nodes of the two buses. Accordingly, light heads on the nested bus provide self-identification and diagnostic information to other nodes such as a computer ( 288 ) configuration utility ( 290 ) featuring a graphical user interface ( 292 ).
1. An array of multiple light heads for a vehicle having a primary Controller Area Network (CAN) serial data bus to carry first serial communications among spaced-apart CAN nodes communicatively coupled thereto, the first serial communications for initiating a light flash sequence from the array, comprising:
a secondary CAN serial data bus for establishing a nested CAN serial data bus carrying, in response to the first serial communications, second serial communications provided to the multiple light heads communicatively coupled thereto, the second serial communications for controlling the light flash sequence from the array;
each of the multiple light heads including light head CAN node circuitry, the light head CAN node circuitry including a light head CAN controller electrically coupled to the secondary CAN serial data bus such that an impedance of the light head CAN node circuitry is electrically isolated from the primary CAN serial data bus when an associated light head is operatively deployed in the vehicle; and
an array controller including first and second CAN node circuitry configured to communicatively segregate and bridge the primary and secondary CAN serial data buses, the first CAN node circuitry including a first CAN controller electrically couplable to the primary CAN serial data bus so as to establish a first CAN node for facilitating the first serial communications, and the second CAN node circuitry including a second CAN controller electrically coupled to the secondary CAN serial data bus so as to establish a second CAN node for facilitating the second serial communications.
2. The array of claim 1 , in which the array comprises a light bar mountable atop a roof of the vehicle.
3. The array of claim 2 , in which the secondary CAN serial data bus includes serial data cabling connecting the multiple light heads, and in which the light bar houses the serial data cabling of the secondary CAN serial data bus.
4. The array of claim 1 , in which the array comprises a safety director mountable atop of the vehicle and arranged to provide a rearward-facing flash pattern.
5. The array of claim 1 , in which the array is mountable to a rear visor of the vehicle.
6. The array of claim 1 , in which the array is a rear-windshield mountable array arranged to provide a rearward-facing flash pattern.
7. The array of claim 1 , in which the array is a front-windshield mountable array arranged proximal a visor to provide a frontward-facing flash pattern.
8. The array of claim 1 , further comprising:
a computer-readable medium including instructions stored thereon that, when executed by a microcontroller of the array controller, configure the array controller to:
in response to receiving a first serial command through the primary CAN serial data bus, process the first serial command to determine a sequence of second serial commands for the multiple light heads; and
in response to determining the sequence of second serial commands, generate the second serial communications according to the sequence so as to control the light flash sequence based on the first serial command.
9. The array of claim 1 , further comprising multiple temperature sensors in which each of the multiple light heads includes a different one of the multiple temperature sensors for communicating temperature information through the secondary CAN serial data bus.
10. The array of claim 1 , in which each of the multiple light heads includes multiple analog-to-digital converter (ADC) channels electrically coupled to corresponding strings of light-emitting diodes (LEDs), the ADC channels configured to measure voltages associated with the corresponding strings of LEDs such that an associated light head is configured to communicate, through the secondary CAN serial data bus, a digital representation of the measured voltages, the digital representation corresponding to a predefined hardware platform of the associated light head.
11. The array of claim 1 , in which the array controller comprises a microcontroller integrated circuit encompassing the first and second CAN node circuitry.
12. The array of claim 1 , in which the array controller comprises first and second microcontrollers communicatively coupled to each other, the first microcontroller including the first CAN node circuitry, and the second microcontroller including the second CAN node circuitry.