Low power sensor communication using two or fewer wires
A sensor module, in some embodiments, comprises a sensor configured to capture data and a sensor interface coupled to the sensor and configured to process the data captured by the sensor to form processed data. The sensor module may also comprise a current consumption configuration component and a transistor coupled to the current consumption configuration component and configured to control the current consumption configuration component to output the processed data.
1. A sensor module, comprising:
a sensor configured to capture data;
wherein the sensor module is configured to couple to a processor;
a sensor interface coupled to the sensor and configured to process the data captured by the sensor to form processed data;
a current consumption configuration component; and
a transistor, coupled to the current consumption configuration component and to the sensor, configured to control the current consumption configuration component to output the processed data to the processor.
2. The sensor module of claim 1 , wherein the sensor module is further configured to draw a first current magnitude from the processor when the sensor captures data and the sensor interface processes the data captured by the sensor.
3. The sensor module of claim 2 , wherein the sensor module is further configured to couple directly to the processor via only one electrical wire, the electrical wire configured to provide power from the processor to the sensor module and communicate the processed data from the sensor module to the processor.
4. The sensor module of claim 2 , wherein the transistor is configured to control the current consumption configuration component to alternate a current draw of the sensor module between the first current magnitude and a second current magnitude less than the first current magnitude to communicate the processed data to the processor.
5. The sensor module of claim 4 , wherein the first current magnitude represents a binary one, and wherein the second current magnitude represents a binary zero.
6. The sensor module of claim 1 , wherein the sensor is an automotive pressure sensor.
7. A method for capturing data and communicating the data from a sensor module to a processor, comprising:
activating a sensor of the sensor module to capture the data;
activating a current source to maintain an approximately constant current draw of a first current magnitude by the sensor module via a first electrical wire when the sensor is activated, the first electrical wire configured to couple the sensor module to the processor to provide power to the sensor module;
storing the data;
deactivating the sensor after the data is captured and stored; and
selectively deactivating and reactivating the current source based on a content of the stored data to communicate the stored data from the sensor module to the processor via the first electrical wire, wherein selectively deactivating and reactivating the current source comprises controlling a transistor coupled to the current source and configured to control the current source to communicate the data from the sensor module to the processor.
8. The method of claim 7 , wherein selectively deactivating and reactivating the current source based on the content of the stored data comprises deactivating the current source to communicate a first value of the stored data and reactivating the current source to represent a second value of the stored data.
9. The method of claim 8 , wherein to communicate the stored data from the sensor module to the processor, the method further comprises drawing a second current magnitude less than the first current magnitude to represent the first value and drawing the first current magnitude to represent the second value.
10. The method of claim 9 , wherein the second current magnitude is an approximately minimum current draw of the sensor module.
11. The method of claim 7 , further comprising activating the sensor to capture second data after communicating the stored data from the sensor module to the processor via the electrical wire.
12. The method of claim 7 , wherein the first current magnitude is approximately 3 milliamps (mA) and the second current magnitude is approximately 1 mA.
13. A system, comprising:
a processor; and
a sensor module coupled to the processor and configured to draw a first magnitude of current from the processor to capture data, the sensor module comprising:
a current source;
a sensor configured to capture the data; and
a transistor configured to control the current source to communicate the data from the sensor module to the processor, wherein the transistor alternates a current draw of the sensor module between the first magnitude of current and a second magnitude of current.
14. The system of claim 13 , wherein the second magnitude of current is less than the first magnitude of current, and wherein, to communicate data to the processor, the sensor module draws the first magnitude of current to represent a first data value and draws the second magnitude of current to represent a second data value.
15. The system of claim 14 , wherein the first data value is a logical high value and the second data value is a logical low value.
16. The system of claim 13 , wherein to control the current source, the transistor selectively activates and deactivates the current source.
17. The system of claim 13 , wherein the sensor is an automobile pressure sensor.
18. The system of claim 13 , wherein the sensor module is configured to couple to the processor via two or fewer electrical wires, and wherein the two or fewer electrical wires are selected from the group consisting of: a power supply electrical wire and a ground electrical wire.