Illuminated switch or indicator with integral data communications device and fail sense function
An aircraft annunciator (illuminated switch or indicator) includes, within a housing sized to fit in the panel cutout for a single pushbutton aviation switch, a bus converter to interface with a multiplexed ARINC serial data bus, in order to monitor a remote item of equipment such as an ADS-B transponder. The annunciator is coupled by selected pins to receive data words from the multiplexed ARINC serial data bus. A watchdog timer is continuously reset by valid messages from the transponder, logically ORed with the power supply as well as external analog fault signals in order to generate an output controlling illumination of an FAA-mandated “ADS-B FAIL” legend on the annunciator.
1. An annunciator, comprising:
a housing having a cross-section sized to fit within a panel cutout accommodating a single pushbutton aviation switch and having a length sufficient to accommodate:
an illumination source positioned within the housing to illuminate a faceplate over a first end of the housing,
at least two connector pins within the housing at a second end of the housing, the at least two connector pins configured to be selectively coupled to a multiplexed serial data bus, and
a bus converter circuit within the housing coupled to process signals from one or more of the at least two connector pins and configured to activate the illumination source in response to a status of one or more data bits on the multiplexed serial data bus.
2. The annunciator of claim 1 , wherein the bus converter circuit comprises:
a bus decoder coupled to the at least two connector pins and configured to receive messages from the multiplexed serial data bus and to output a first signal as long as at least one valid message is received from the remote equipment during a predetermined period and to output a second signal when no valid message is received from the remote equipment during the predetermined period.
3. The annunciator of claim 2 , wherein the bus converter circuit is further configured to activate the illumination source in response to one of an absence of a power supply signal or receipt of a signal indicating an external analog condition.
4. The annunciator of claim 3 , wherein the bus converter circuit comprises:
a power supply circuit configured to receive a power supply signal and to output a first signal when the power supply circuit signal is not received;
a fail sense circuit configured to receive outputs from the bus decoder and the power supply circuit and to cause a fail signal to be output based on a logical combination of the outputs from the bus decoder and the power supply circuit.
5. The annunciator of claim 1 , wherein the bus converter circuit comprises:
a bus decoder coupled to the at least two connector pins and configured to
receive messages from the multiplexed serial data bus,
process the received data bits, and
output a signal on one or more of the at least two connector pins based on the processing results.
6. The annunciator of claim 1 , wherein the fail sense circuit is further configured to receive at least one external analog fault signal and to cause the fail signal to be output based on a logical combination of the output from the bus decoder, the output from the power supply circuit, and the at least one external analog fault signal.
7. The annunciator of claim 1 , further comprising:
a plurality of switches within the housing, wherein the bus converter circuit is configured to transmit a signal on the multiplexed serial data bus in response to actuation of one of the switches.
8. The annunciator of claim 1 , wherein the bus converter circuit is configured to transmit a signal on the multiplexed serial data bus in response to signals received on one or more of the at least two connector pins.
9. The annunciator of claim 1 , wherein the bus converter circuit comprises:
a bus decoder coupled to the at least two connector pins and configured to
process input signals from one or more of the at least two connector pins, and
transmit messages on the multiplexed serial data bus containing the processed results.
10. The annunciator of claim 1 , wherein the remote equipment comprises an automatic dependent surveillance broadcast (ADS-B) transponder and wherein the faceplate includes a lens cap legend “ADS-B FAIL”.
11. The annunciator of claim 1 , further comprising:
a first flex substrate on which the bus converter circuit is formed, the first flex substrate folded around an elastomeric, three-dimensional rectangle and positioned on a pin holder in which a plurality of pins are mounted, the plurality of pins including the at least two connector pins configured to be selectively coupled to the multiplexed serial data bus;
a second flex substrate on which pin connection conductors are formed for electrically coupling selected pins within the plurality of pins to an array of light emitting diodes (LEDs) forming the illumination source, the second flex substrate wrapped around the folded first flex substrate and the elastomeric, three-dimensional rectangle; and
a plastic cover retaining the first and second flex substrates in position on the pin holder.
12. A method for forming an annunciator, comprising:
providing a housing having a cross-section sized to fit within a panel cutout accommodating a single pushbutton aviation switch and having a length sufficient to contain an illumination source, at least two connector pins, and a bus converter circuit;
positioning the illumination source within the housing to illuminate a faceplate over a first end of the housing;
providing the at least two connector pins within the housing at a second end of the housing, the at least two connector pins configured to be selectively coupled to a multiplexed serial data bus;
coupling the bus converter circuit within the housing to process signals from one or more of the at least two connector pins; and
configuring the bus converter circuit to activate the illumination source in response to a status of one or more data bits on the multiplexed serial data bus.
13. The method of claim 12 , wherein the bus converter circuit comprises:
a bus decoder coupled to the at least two connector pins and configured to receive messages from the multiplexed serial data bus and to output a first signal as long as at least one valid message is received from the remote equipment during a predetermined period and to output a second signal when no valid message is received from the remote equipment during the predetermined period.
14. The method of claim 12 , wherein the bus converter circuit is further configured to activate the illumination source in response to one of an absence of a power supply signal or receipt of a signal indicating an external analog condition.
15. The method of claim 14 , wherein the bus converter circuit comprises:
a power supply circuit configure to receive a power supply signal and to output a first signal when the power supply circuit is not received;
a fail sense circuit configured to receive outputs from the bus decoder and the power supply circuit and to cause a fail signal to be output based a logical combination of the outputs from the bus decoder and the power supply circuit.
16. The method of claim 12 , wherein the bus converter circuit comprises a bus decoder coupled to the at least two connector pins, wherein the method further comprises:
receiving messages from the multiplexed serial data bus;
processing the received data bits; and
outputting a signal on one or more of the at least two connector pins based on the processing results.
17. The method of claim 12 , wherein the fail sense circuit is further configured to receive at least one external analog fault signal and to cause the fail signal to be output based on a logical combination of the output from the bus decoder, the output from the power supply circuit, and the at least one external analog fault signal.
18. The method of claim 12 , further comprising:
providing a plurality of switches within the housing, wherein the bus converter circuit is configured to transmit a signal on the multiplexed serial data bus in response to actuation of one of the switches.
19. The method of claim 12 , wherein the bus converter circuit is configured to transmit a signal on the multiplexed serial data bus in response to signals received on one or more of the at least two connector pins.
20. The method of claim 12 , wherein the bus converter circuit comprises a bus decoder coupled to the at least two connector pins, the method further comprising:
processing input signals from one or more of the at least two connector pins; and
transmitting messages on the multiplexed serial data bus containing the processed results.
21. The method of claim 12 , wherein the remote equipment comprises an automatic dependent surveillance—broadcast (ADS-B) transponder and wherein the faceplate includes a lens cap legend “ADS-B FAIL”.
22. The method of claim 12 , further comprising:
providing a first flex substrate on which the bus converter circuit is formed, the first flex substrate folded around an elastomeric, three-dimensional rectangle and positioned on a pin holder in which a plurality of pins are mounted, the plurality of pins including the at least two connectors;
providing a second flex substrate on which pin connection conductors are formed for electrically coupling selected pins within the plurality of pins to an array of light emitting diodes (LEDs) forming the illumination source, the second flex substrate wrapped around the folded first flex substrate and the elastomeric, three-dimensional rectangle; and
positioning a plastic cover to retain the first and second flex substrates in position on the pin holder.
23. An annunciator, comprising:
a housing;
an illumination source positioned within the housing to illuminate a faceplate over a first end of the housing;
at least two connector pins within the housing at a second end of the housing, the at least two connector pins configured to be selectively coupled to a multiplexed serial data bus; and
a bus interface module within the housing between the illumination source and the at least two connector pins, the bus interface module including:
a bus converter circuit coupled to receive signals from the at least two connector pins and configured to activate the illumination source in response to a status of one or more data bits on the multiplexed serial data bus,
a first flex substrate on which the bus converter circuit is formed, the first flex substrate folded around an elastomeric, three-dimensional rectangle and positioned on a pin holder in which a plurality of pins are mounted, the plurality of pins including the at least two connector pins,
a second flex substrate on which pin connection conductors are formed for electrically coupling selected pins within the plurality of pins to an array of light emitting diodes (LEDs) forming the illumination source, the second flex substrate wrapped around the folded first flex substrate and the elastomeric, three-dimensional rectangle, and a plastic cover retaining the first and second flex substrates in position on the pin holder.
24. The annunciator of claim 23 , wherein the bus converter circuit comprises:
a bus decoder coupled to the at least two connector pins and configured to receive messages from the multiplexed serial data bus and to output a first signal as long as at least one valid message is received from the remote equipment during a predetermined period and to output a second signal when no valid message is received from the remote equipment during the predetermined period.
25. The annunciator of claim 23 , wherein the bus converter circuit is further configured to activate the illumination source in response to one of an absence of a power supply signal or receipt of a signal indicating an external analog fault condition, wherein the bus converter circuit comprises:
a power supply circuit configured to receive a power supply signal and to output a first signal when the power supply circuit signal is not received;
a fail sense circuit configured to receive the output from the bus decoder, the output from the power supply circuit, and at least one external analog fault signal, and wherein the fail sense circuit further configured to cause a fail signal to be output based a logical combination of the output from the bus decoder, the output from the power supply circuit, and the at least one external analog fault signal.
26. The annunciator of claim 23 , wherein the remote equipment comprises an automatic dependent surveillance broadcast (ADS-B) transponder and wherein the faceplate includes a lens cap legend “ADS-B FAIL”.