External activation of quiescent device
After installation, a device may be not yet powered. It may be awakened by receiving a flash of light of sufficient frequency and amplitude. After waking, the device decodes the message to determine its next action, and, upon request sends an authentication message. This enables a single user action to wake the device up and set it up with networking credentials. The same process may be used to wake the device outside of a normal sleep-wake cycle.
1. A device capable of external activation comprising:
a light detection circuit adapted to receive a light signal from a light source;
a high pass filter coupled to the light detection circuit that when receiving light of at least a given intensity produces a spike;
a power manager chip coupled to the light detection circuit that upon receipt of the spike enables power to a microcontroller;
a component capable of inhabiting: a detection state in which:
a spike is detected; and when a spike is found, a spike counter is incremented;
a timer that measures a time between spikes;
wherein when the time between spikes exceeds an END OF WORD length, the spike counter is cleared;
wherein when the spike counter reaches a wakeup threshold then subsequent spikes and delay lengths are interpreted as a transmitted message; and
wherein the wakeup threshold is of sufficient length to allow the microcontroller to boot.
2. The device of claim 1 , wherein the transmitted message is in modified morse code.
3. The device of claim 2 , wherein in the modified morse code a DOT is a delay of 1 time duration, a DASH is a delay of 3 time durations, and END OF PART OF A LETTER is a delay of 1 time duration, an END OF LETTER is a delay of 5 time durations, and an END OF WORD is a delay of 9 time durations.
4. The device of claim 3 , wherein the transmitted message comprises a message portion and an authentication portion.
5. The device of claim 4 , wherein the delay of one time duration is about 8 ms.
6. The device of claim 5 , wherein the light detection circuit adapted to receive a light signal from a light source is adapted to receive multiple spikes separated in time as the light signal.
7. The device of claim 6 , wherein the transmitted message is at least partially stored in a buffer.
8. The device of claim 6 , wherein the light detection circuit adapted to receive a light signal from a light source is adapted to receive multiple messages as the light signal.
9. The device of claim 8 , further comprising the component capable of inhabiting:
receiving an out-of-bound authentication request; and
transmitting contents of the buffer in the memory.
10. The device of claim 1 , wherein the light detection circuit is adapted to generate a spike based on the light signal.
11. A device with a microcontroller, memory, and transmitter comprising:
a light detection circuit operationally able to receive a light signal from a light source, and operationally able to use the light signal to signal a power management circuit;
the power management circuit operationally able to boot up the microcontroller;
the microcontroller operationally able to scan the light signal for a message; and
the transmitter operationally able to transmit at least a portion of the message;
wherein the message is encoded in modified morse code; wherein a DOT is a signal of one time duration, a DASH is a signal of 3 time durations, an END OF LETTER is a signal of 5 time durations; and an END OF WORD is a signal of 9 time durations.
12. The device of claim 11 , wherein one time duration comprises a time of about 8 ms.
13. The device of claim 12 , wherein one time duration comprises a time of about 10 ms.
14. The device of claim 13 , wherein the message comprises a message portion followed by an authentication portion.
15. The device of claim 14 , further comprising a filter, wherein the filter is a high pass filter.
16. A method implemented by a device with one or more computers with memory, one or more processors, a light detection circuit, a high pass filter, and a transmitter comprising:
receiving a light signal by the light detection circuit;
the light detection circuit passing the light signal to a filter, the filter producing a series of spikes of at least a threshold intensity when the light signal is of sufficient intensity, the spikes a multiple of a base time apart;
reading a message upon a receipt of one of the series of spikes; and
wherein the message is encoded in modified morse code; wherein a DOT is a signal of one time duration, a DASH is a signal of 3 time durations, an END OF LETTER is a signal of 5 time durations; and an END OF WORD is a signal of 9 time durations.
17. The method of claim 16 , wherein the message comprises a message portion and an authentication portion.
18. The method of claim 16 , further comprising:
detecting a spike;
measuring a delay length between a single spike and a subsequent spike;
when the spike is detected, incrementing a spike counter;
when the delay length exceeds the END OF WORD, clearing the spike counter, and
when the spike counter reaches a wakeup threshold then interpreting subsequent spike-delay lengths as a transmitted message.
19. The method of claim 18 , wherein the transmitted message is two letters in modified morse code and a third authentication letter in modified morse code.
20. The method of claim 18 , wherein a high-pass filter is applied to the spike.