Card reader with power efficient architecture that includes a power supply and a wake up circuit
View Patent ↗These and other objects of the present invention are achieved in a card reader with a read head positioned in a housing. The read head is configured to be coupled to a mobile device and has a slot for swiping a magnetic stripe of a card. The read head reads data on the magnetic stripe and produces a raw magnetic signal indicative of data stored on the magnetic stripe. A power supply is coupled to wake-up electronics and a microcontroller. An output jack is adapted to be inserted in a port of the mobile device and deliver an output jack signal to the mobile device.
1. A card reader, comprising:
a housing;
a read head positioned in the housing, the read head configured to be coupled to a mobile device, the read head having a slot for swiping a magnetic stripe of a card, the read head configured to produce a first signal indicative of data stored on the magnetic stripe;
wake-up electronics configured to send a wake-up signal to a microcontroller to wake up device electronics of the card reader device from a sleep state to an active state in response to the magnetic stripe being swiped through the read head, the device electronics configured to, in the active state, receive the first signal from the read head and convert the first signal into a second signal;
a power supply coupled to the wake-up electronics and the microcontroller, wherein the microcontroller is configured to wake up the device electronics from the sleep state to the active state and the microcontroller further configured to power down the wake-up electronics when the device electronics transition to the active state and to power up the wake-up electronics when the device electronics return to the sleep state; and
an output jack adapted to be inserted in a port of the mobile device and to deliver through the output jack the second signal to the mobile device.
2. The card reader of claim 1 , wherein the second signal is an encrypted second signal.
3. The card reader of claim 1 , wherein the second signal is an encrypted and signed second signal.
4. The card reader of claim 1 , further comprising:
device electronics that includes the microcontroller and an analog to digital front-end.
5. The card reader of claim 4 , wherein the analog to digital front end is coupled to a processing element in the microcontroller, the analog to digital front end receiving a first signal and converting the first signal into a processed digital signal that the microcontroller can interpret, the microcontroller producing a signal.
6. The card reader of claim 4 , wherein the front end includes, an amplifier or filter, differentiator, a comparator and the wake-up electronics.
7. The card reader of claim 1 , wherein the wake-up electronics is a wake-up circuit.
8. The card reader of claim 1 , wherein the wake-up electronics utilize an op-amp.
9. The card reader of claim 1 , wherein the wake-up electronics utilize an op-amp, a discrete transistor, and associated passive components.
10. The card reader of claim 1 , wherein the wake-up electronics detects when there is an edge from leading zeros of a card being swiped and alerts to wake up the microcontroller and device electronics.
11. The card reader of claim 4 , wherein the device electronics wakes up in enough time to process and encrypt a card swipe signal.
12. The card reader of claim 4 , wherein the device electronics includes an amplifier/filter, differentiator, comparator, transmission electronics, and the microcontroller.
13. The card reader of claim 12 , wherein the first signal is amplified by the amplifier/filter and processed before the microcontroller accepts it as an input.
14. The card reader of claim 13 , wherein the differentiator takes the output of the amplifier/filter and differentiates it, looking for peaks in the input signal.
15. The card reader of claim 14 , wherein the comparator takes the output of the differentiator and compares it to a reference voltage and produces an output that is a processed digital version of a magnetic swipe.
16. The card reader of claim 15 , wherein the comparator looks for where an input signal crosses zero.
17. The card reader of claim 16 , wherein the microcontroller accepts the comparator input, processes the comparator input and encrypts at least a portion of data of the comparator input.
18. The card reader of claim 17 , wherein the microcontroller controls power to the amplifier/filter, differentiator and comparator.
19. The card reader of claim 18 , wherein the comparator is included as part of the microcontroller.
20. The card reader of claim 12 , wherein the transmission electronics accepts output data of the micro controller as an input and uses this to modulate a microphone-bias line of the mobile device.
21. The card reader of claim 20 , wherein the microphone-bias line is used both for power and for data transmission back to the mobile device.
22. The card reader of claim 1 , wherein the second signal is a synchronous Manchester encoded stream.
23. The card reader of claim 1 , wherein the second signal is a synchronized stream.
24. A card reader, comprising:
a housing;
a read head positioned in the housing, the read head configured to be coupled to a mobile device, the read head having a slot for swiping a magnetic stripe of a card, the read head configured to produce a first signal indicative of data stored on the magnetic stripe;
wake-up electronics configured to send a wake-up signal to a microcontroller to wake up device electronics of the card reader device from a sleep state to an active state in response to the magnetic stripe being swiped through the read head, the device electronics configured to, in the active state, receive the first signal from the read head and convert the first signal into a second signal, wherein the microcontroller is configured to wake up the device electronics from the sleep state to the active state and the microcontroller further configured to power down the wake-up electronics when the device electronics transition to the active state and to power up the wake-up electronics when the device electronics return to the sleep state; and
wherein the second signal sent to the mobile device is at a frequency such that the second signal is an alternating current in relation to the port of the mobile device.
25. The card reader of claim 24 , wherein the frequency of the second signal is 2 KHz to 48 kHz.
26. The card reader of claim 24 , wherein the frequency of the second signal is 2.4 kHz.
27. A card reader, comprising:
a housing;
a read head positioned in the housing, the read head configured to be coupled to a mobile device, the read head having a slot for swiping a magnetic stripe of a card, the read head configured to produce a first signal indicative of data stored on the magnetic stripe;
wake-up electronics configured to send a wake-up signal to a microcontroller to wake up device electronics of the card reader device from a sleep state to an active state in response to the magnetic stripe being swiped through the read head, the device electronics configured to, in the active state, receive the first signal from the read head and convert the first signal into a second signal, wherein the microcontroller is configured to wake up the device electronics from the sleep state to the active state and the microcontroller further configured to power down the wake-up electronics when the device electronics transition to the active state and to power up the wake-up electronics when the device electronics return to the sleep state; and
wherein the microcontroller has a non-volatile memory with a size of 2-8 kbytes, and RAM with a size 128-512 bytes.
28. A card reader, comprising:
a housing;
a read head positioned in the housing, the read head configured to be coupled to a mobile device, the read head having a slot for swiping a magnetic stripe of a card, the read head configured to produce a first signal indicative of data stored on the magnetic stripe;
wake-up electronics configured to send a wake-up signal to a microcontroller to wake up device electronics of the card reader device from a sleep state to an active state in response to the magnetic stripe being swiped through the read head, the device electronics configured to, in the active state, receive the first signal from the read head and convert the first signal into a second signal, wherein the microcontroller is configured to wake up the device electronics from the sleep state to the active state and the microcontroller further configured to power down the wake-up electronics when the device electronics transition to the active state and to power up the wake-up electronics when the device electronics return to the sleep state; and
wherein the read head sends a signal to the mobile device at a constant baud rate.
29. The card reader of claim 1 , wherein the wake-up electronics are configured to be powered by a microphone bias of the mobile device, and the device electronics are configured to be powered by an internal battery power within the housing of the card reader.