LED light bar for optical traffic control systems
Various approaches for activating a traffic control preemption system. A light bar includes a support structure and a plurality of LED modules individually mounted on the support structure. Each LED module includes a plurality of LED groups, and in at least one of the plurality of LED modules, at least one LED group in the module is an infrared (IR) LED group, and at least one LED group in the module is a visible light LED group. A controller is coupled to each module. The controller is configured to trigger an IR light pulse pattern at a first level of IR radiant power from the at least one IR LED group. The pulse pattern and first level of IR radiant power activate preemption in a traffic control preemption system.
1. A light bar comprising:
a support structure;
a plurality of LED modules individually mounted on the support structure, each LED module including a plurality of LED groups, wherein in at least one of the plurality of LED modules, at least one LED group in the module is an infrared (IR) LED group, and at least one LED group in the module is a visible light LED group; and
a controller coupled to each module, wherein the controller is configured to trigger an IR light pulse pattern at a first level of IR radiant power from the at least one IR LED group, and the pulse pattern and first level of IR radiant power activate preemption in a traffic control preemption system, the controller further configured to trigger the at least one visible LED group to emit a flash pattern.
2. The light bar of claim 1 , further comprising at least one halogen lamp module including a halogen lamp mounted on the support structure.
3. The light bar of claim 1 , further comprising at least one gas discharge lamp module including a gas discharge lamp mounted on the support structure.
4. The light bar of claim 1 , further comprising:
wherein two or more of the LED groups are IR LED groups;
a plurality of controlled current sources coupled to the IR LED groups, respectively;
wherein the controller is coupled to the plurality of controlled current sources and is further configured to trigger the IR light pulse pattern from the IR LED groups and maintain the first level of IR radiant power from the IR LED groups using individual control of respective current levels to the IR LED groups in response to current sense levels from the IR LED groups.
5. The light bar of claim 4 , wherein the controller is further configured, responsive to the current sense level from one of the IR LED groups indicating to the controller that the one IR LED group has failed, to increase the respective current levels to each IR LED group other than the failed IR LED group.
6. The light bar of claim 1 , further comprising a plurality of temperature sensors proximate the LED modules having an IR LED group, respectively, wherein each temperature sensor is coupled to the controller, and the controller is further configured, responsive to temperature levels from the temperature sensors, to adjust respective current levels to the at least one IR LED group.
7. The light bar of claim 1 , wherein two or more of the LED groups are IR LED groups, and the controller is further configured to trigger a subset of the IR LED groups for each pulse of the pulse pattern, the subset including fewer than all of the IR LED groups.
8. The light bar of claim 1 , wherein two or more of the LED groups are IR LED groups, the light bar further comprising:
at least one IR sensor coupled to the controller, wherein the IR sensor is mounted to receive the IR pulse pattern from the two or more IR LED groups and output a sensed level of IR radiant power of the IR LED groups; and
wherein the controller is further configured to adjust respective current levels to the IR LED groups in response to the sensed level of IR radiant power for maintaining the first level of IR radiant power.
9. The light bar of claim 1 , wherein the controller is configurable with a parameter for specifying different levels of IR radiant power.
10. The light bar of claim 1 , wherein two or more of the LED groups are IR LED groups, the pulse pattern that activates preemption in the traffic control preemption system is a first pulse pattern, and the controller is further configured to trigger a second IR light pulse pattern from the IR LED groups, and the second pulse pattern is different from the first pulse pattern.
11. The light bar of claim 1 , further comprising a plurality of respective pulse energy storage devices, each coupled to a respective one of the LED groups.
12. The light bar of claim 1 , further comprising:
wherein two or more of the LED groups are IR LED groups;
a plurality of voltage controlled current sources coupled to the IR LED groups, respectively;
wherein the controller is coupled to the plurality of voltage controlled current sources and is further configured to trigger the IR light pulse pattern from the IR LED groups and maintain the first level of IR radiant power from the IR LED groups using individual control of respective current levels to the IR LED groups in response to current sense levels from the IR LED groups.
13. The light bar of claim 1 , wherein the controller is further configured to count a number of pulses emitted by the at least one IR LED group and responsive to the count reaching a threshold, to increase the current levels to the at least one IR LED group.
14. A light bar comprising:
a support structure;
a plurality of LED modules mounted on the support structure, each LED module including a plurality of LED groups, and in two or more of the plurality of LED modules, at least one LED group is an infrared (IR) LED group and at least one LED group is a visible light LED group;
a plurality of capacitors coupled to the LED groups, respectively;
a plurality of controlled current sources coupled to the IR LED groups, respectively;
at least one trigger switch coupled to the controlled current sources; and
a microcontroller coupled to the at least one trigger switch, wherein the microcontroller is configurable with a parameter for specifying different levels of IR radiant power and is configured to trigger an IR light pulse pattern from the IR LED groups and maintain a first level of IR radiant power from the IR LED groups using individual control of respective current levels to the IR LED groups in response to current sense levels from the IR LED groups, wherein the pulse pattern and first level of IR radiant power activate preemption in the traffic control preemption system, the microcontroller further configured to trigger the at least one visible LED group to emit a flash pattern.
15. The light bar of claim 14 , further comprising at least one halogen lamp module including a halogen lamp mounted on the support structure.
16. The light bar of claim 14 , further comprising at least one gas discharge lamp module including a gas discharge lamp mounted on the support structure.
17. The light bar of claim 14 , wherein the microcontroller is further configured, responsive to the current sense level from one of the IR LED groups indicating to the microcontroller that the one IR LED group has failed, to increase the respective current levels to each IR LED group other than the failed IR LED group.
18. The light bar of claim 14 , further comprising a plurality of temperature sensors proximate the LED modules having an IR LED group, respectively, wherein each temperature sensor is coupled to the microcontroller, and the microcontroller is further configured, responsive to temperature levels from the temperature sensors, to adjust the respective current levels to the IR LED groups.
19. The light bar of claim 14 , wherein the microcontroller is further configured to trigger a subset of the IR LED groups for each pulse of the pulse pattern, the subset including fewer than all of the IR LED groups.
20. The light bar of claim 14 , further comprising:
at least one IR sensor coupled to the microcontroller, wherein the IR sensor is mounted to receive the IR pulse pattern from the IR LED groups and output a sensed level of IR radiant power of the IR LED groups; and
wherein the controller is further configured to adjust respective current levels to the IR LED groups in response to the sensed level of IR radiant power for maintaining the first level of IR radiant power.
21. A light bar for a traffic control preemption system, comprising:
a plurality of LED modules, each LED module including a plurality of LED groups, wherein in two or more of the LED modules, at least one LED group in the module is an infrared (IR) LED group, and at least one LED group in the module is a visible light LED group;
means for supporting the plurality of LED modules on a vehicle;
means for providing power to the LED groups;
means for controlling current to the plurality of LED groups;
programmable means for triggering an IR light pulse pattern at a first level of IR radiant power from the IR LED groups and for maintaining a first level of IR radiant power from the IR LED groups using individual control of respective current levels to the IR LED groups in response to current sense levels from the IR LED groups, wherein the pulse pattern and first level of IR radiant power activate preemption in the traffic control preemption system; and
means for triggering the at least one visible LED group to emit a flash pattern.