Last known state across a plurality of dispersed geographic sensors synchronized to a common clock
A system to coordinate event data from a plurality of smart sensor devices that are coupled to streetlight fixtures to generate a last known state across the plurality of smart sensor devises. The plurality of smart sensor devices receive a distributed clock that is common among the smart sensor devices. A local clock of each smart sensor device is synchronized to the distributed clock. Each smart sensor device monitors and stores event data in an incident buffer. The stored event data is correlated to the distributed clock. The stored correlated event data is transmitted to a remote server. The remote server aggregates the correlated event data from the plurality of smart sensor devices based on the distributed clock to generate a last known state across the plurality of smart sensor devices.
1. A system comprising:
a plurality of smart sensor devices coupled to respective streetlight fixtures of a plurality of streetlight fixtures, wherein each smart sensor device includes:
a GPS receiver arranged to receive GPS signals that include a distributed clock;
a transceiver arranged to transmit stored correlated event data;
a local clock circuit arranged to supply a local clock signal to circuitry of the smart sensor device, wherein the local clock signal is synchronized to the distributed clock;
a local memory arranged to store event data; and
a processor-based event-monitoring circuit arranged to receive event data captured by a sensor, correlate the event data with the distributed clock based on the synchronized local clock signal, and store the correlated event data in the local memory; and
a remote server that includes:
a memory arranged to store the correlated event data received from the plurality of smart sensor devices; and
a processor arranged to execute computer instructions stored in the memory, which when executed cause the processor to:
aggregate the correlated event data from the plurality of smart sensor devices based on the distributed clock; and
generate a current system state across the plurality of smart sensor devices from the aggregated event data and synchronized to the distributed clock.
2. The system of claim 1 , wherein the current system state is a last known state before at least one of a power failure, a failure of at least one of the plurality of smart sensor devices, a failure of at least one of the plurality of streetlight fixture, and a determined environmental condition.
3. The system of claim 1 , wherein the processor-based event-monitoring circuit of each of the plurality of smart sensor devices is further arranged to transmit the correlated event data to the remote server in response to an external incident.
4. The system of claim 1 , wherein the processor of the remote server is arranged to execute additional computer instructions that, when executed, cause the processor to send a request to each of the plurality of smart sensor devices requesting each of the plurality of smart sensor devices to transmit the correlated event data currently stored in their local memory to the remote server.
5. The system of claim 4 , wherein the request is sent to each of the plurality of smart sensors in response to an incident.
6. The system of claim 1 , wherein the processor of the remote server is arranged to execute additional computer instructions that, when executed, cause the processor to send to each respective smart sensor device of the plurality of smart sensor devices a selection of events to be monitored by the respective smart sensor device.
7. The system of claim 1 , wherein the processor-based event-monitoring circuit is further arranged to receive a selection of events to monitor for the event data.
8. The system of claim 1 , wherein the local memory of each of the plurality of smart sensor devices is a non-transitory memory that temporarily stores the correlated event data in a first-in-first-out configuration.
9. The system of claim 1 , wherein each of the plurality of smart sensor devices includes:
at least one interface that is coupled to at least one sensor that is selected from the group consisting of a tilt sensor, an accelerometer, a temperature sensor, a power metering sensor, a camera, a microphone, a humidity sensor, a rain collection sensor, and a wind sensor.
10. A smart sensor device attachable to a streetlight fixture, the smart sensor device comprising:
a GPS receiver arranged to receive GPS signals that include a distributed clock;
a local clock circuit arranged to supply a local clock signal to circuitry of the smart sensor device, wherein the local clock signal is synchronized to the distributed clock;
a local, non-volatile memory arranged to store sensor-based data;
a sensor arranged to capture event data;
a processor-based event-monitoring circuit arranged to receive the captured event data from the sensor, correlate the event data with the distributed clock based on the synchronized local clock signal, and store the correlated event data in the memory; and
a transceiver arranged to transmit the stored correlated event data to a remote server.
11. The smart sensor device of claim 10 , wherein the local, nonvolatile memory stores the correlated event data in a first-in-first-out configuration.
12. The smart sensor device of claim 10 , further comprising:
a receiver that receives, from the remote server, a selection of events to monitor via the sensor for the event data.
13. The smart sensor device of claim 10 , wherein the local clock circuit is further arranged to resynchronize the local clock signal to the distributed clock in response to a difference between the local clock signal and a new distributed clock that is included in a GPS signal.
14. The smart sensor device of claim 10 , wherein the transceiver is arranged to transmit the stored correlated event data to the remote server in response to an external incident.
15. The smart sensor device of claim 10 , further comprising:
a connector for coupling the smart sensor device to a streetlight fixture.
16. The smart sensor device of claim 10 , wherein the sensor is selected from the group consisting of a tilt sensor, an accelerometer, a temperature sensor, a power metering sensor, a camera, a microphone, a humidity sensor, a rain collection sensor, and a wind sensor.
17. A method comprising,
receiving a selection of events to monitor for each of a plurality of smart sensor devices coupled to respective streetlight fixtures of a plurality of streetlight fixtures;
providing the selection of events to the plurality of smart sensor devices;
identifying an occurrence of an incident associated with the plurality of streetlight fixtures;
receiving, from each of the plurality of smart sensor devices, event data that is correlated to a distributed clock received by GPS receivers of the plurality of smart sensor devices;
aggregating the correlated event data based on the distributed clock; and
generating a current state of the plurality of smart sensor devices prior to the occurrence of the incident.
18. The method of claim 17 , further comprising:
sending a request for the correlated event data in response to the occurrence of the incident; and
receiving, from each of the plurality of smart sensor devices, the correlated event data in response to the request.
19. The method of claim 17 , further comprising:
providing the last known state of the plurality of smart sensors to a user.
20. The method of claim 17 , wherein the current system state is a last known state of the plurality of smart sensor devices prior to the occurrence of the incident.