Method and system for synchronized distributed display over multiple client devices
Portable interactive devices of audience members are remotely operated to substantially “simultaneously” respond to a signal from an origin, e.g., a central server, despite variation in latencies among the devices in order to produce a shared experience. The audience members are reached through varying communication links. Latencies vary among portable interactive devices and among carriers. A firing time for the portable interactive devices is selected to occur at a time in the future. An execution time at which a respective portable interactive device is commanded to operate is a function of the firing time minus the latency control signal reaches clients in a venue in an audience or at a remote location simultaneously despite the varying latencies.
1. A system for operating a plurality of portable interactive devices to perform a commanded function at a firing time in order to produce a shared experience in an event, comprising:
a server producing a command signal comprising information to command performance of the function by a portable interactive device at an execution time;
a communications link for communicating outputs from said server to a set of portable interactive devices;
a program to issue command signals via the server to the set of portable interactive devices;
a time protocol measuring circuit including a time-tagged signal generator coupled to transmit signals to portable interactive devices and a comparator to compare time-tagged signals to a computer clock time and produce a latency for a respective portable device;
a latency register coupled to store the measured latencies; and
the server including an arithmetic unit arranged to calculate an execution time for each respective portable interactive device as a function of the firing time minus value of a respective latency.
2. The system according to claim 1 further comprising a function circuit receiving the values of the signals and calculating a maximum time difference to be selected between the firing time and earliest execution time.
3. The system according to claim 2 comprising an arithmetic circuit coupled to read a latency signal from a respective portable interactive device and subtract the latency signal value from the calculated maximum time difference.
4. The system according to claim 3 wherein said server generates a command signal to the respective portable interactive device to provide a command instructing the portable interactive device to execute at a time in the future as a function of current device latency and the calculated maximum difference.
5. The system according to claim 4 comprising a circuit defining a time window defining a tolerance for the time of execution by each portable interactive device and the firing time.
6. The system according to claim 5 wherein said server provides a command for execution by the portable interactive devices upon calculation of the maximum time delay.
7. The system according to claim 6 wherein the time protocol is a Network Time Protocol (NTP).
8. The system according to claim 2 comprising a circuit adapting periodically measured respective latency of portable interactive devices and dynamically recalculating the latency for each device.
9. The system according to claim 3 wherein said signal generation circuit further comprises means for constructing packets to send messages in words to all clients.
10. The system according to claim 9 where a command is selected which causes the portable interactive devices to perform a preselected function.
11. A method for operating a plurality of portable interactive devices to produce a shared experience in an event, comprising:
repeatedly providing a command signal from a server for transmission to a set of portable interactive devices, the command signal comprising information to command performance of a function by the portable interactive devices;
measuring by a time protocol the latency of each portable interactive device by comparing time-tagged signals to a computer clock time;
selecting a firing time at a time in the future at which substantially all of the portable interactive devices perform a commanded function;
selecting an execution time for each respective portable interactive device; and
creating the command signal by calculating an execution time as a function of the firing time minus latency of the respective portable interactive device.
12. The method according to claim 11 comprising operating a control circuit by the server to initiate transmissions of the command signals.
13. The method according to claim 11 wherein the step of selecting an execution time comprises reading a signal for a respective portable interactive device and subtracting the latency from the firing time.
14. The method according to claim 13 wherein a step of selecting a maximum delay comprises reading at least a sampling of latency values and selecting a maximum permissible difference between execution time and firing time.
15. A non-transitory machine-readable medium that provides instructions, which when executed by a processor, causes said processor to perform operations comprising:
repeatedly providing a command signal from a server for transmission to a set of portable interactive devices, the command signal comprising information to command performance of a function by the portable interactive devices;
measuring by a time protocol the latency of each portable interactive device by comparing time-tagged signals to a computer clock time;
selecting a firing time at a time in the future at which substantially all of the portable interactive devices perform a commanded function;
selecting an execution time for each respective portable interactive device; and
creating the command signal by calculating an execution time as a function of the firing time minus latency of the respective portable interactive device.
16. The non-transitory machine-readable medium according to claim 15 wherein the instruction to measure by a time protocol comprises utilizing a Network Time Protocol (NTP).