Device and method for preventing campus card from losing and forgetting

An anti-forgotten, campus card technology, applied to instruments, alarms, etc., can solve problems such as bus cards, campus cards forgotten somewhere, and campus cards taken away

Inactive Publication Date: 2013-04-03
BEIJING UNION UNIVERSITY
5 Cites 3 Cited by

AI-Extracted Technical Summary

Problems solved by technology

We often encounter such a situation, the bus card, campus card will often be forgotten somewhere
Or...
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Method used

[0036] As shown in Figure 2, the wireless transceiver module of the present invention is nRF24L01 radio frequency chip. nRF24L01 is a new single-chip radio frequency transceiver device, working in the 2.4 GHz-2.5 GHz ISM frequency band. nRF24L01 has built-in frequency synthesizer, power amplifier, crystal oscillator, modulator and other functional modules, and incorporates enhanced Sho...
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Abstract

The invention discloses a device and a method for preventing a campus card from losing and forgetting. The device comprises the campus card and a card sleeve, wherein the campus card and the card sleeve are respectively provided with a transmitting circuit and a receiving circuit; a wireless transmitting module in the transmitting circuit is set to be in a transmitting mode; a wireless receiving module in the receiving circuit is set to be in a receiving mode; the transmission module is used for transmitting a radio-frequency signal to the receiving module; and when the distance between the campus card and the card sleeve exceeds a set safety distance, the receiving module can not receive the radio-frequency signal and then controllers on the campus card and the card sleeve simultaneously control buzzers to send out an alarm signal. Radio frequency chips nRF24L01 are used as wireless receiving and transmitting modules for receiving and transmitting signals; and when the distance between the campus card and the card sleeve exceeds a certain distance, the buzzers on the campus card and the card sleeve can send out alarm to remind a card holder of forgetting to take the card, and therefore the card is prevented from being lost.

Application Domain

Alarms

Technology Topic

Radio frequency signalAlarm signal +2

Image

  • Device and method for preventing campus card from losing and forgetting
  • Device and method for preventing campus card from losing and forgetting
  • Device and method for preventing campus card from losing and forgetting

Examples

  • Experimental program(1)

Example Embodiment

[0028] The present invention will be described more fully below with reference to the accompanying drawings, in which exemplary embodiments of the present invention are illustrated.
[0029] The campus card anti-lost and anti-forgetting device provided by the present invention includes a campus card and a card sleeve, wherein a transmitting circuit and a receiving circuit are respectively provided on the campus card and the card sleeve. figure 1 It is a schematic structural diagram of a transmitting circuit and a receiving circuit of a device for preventing loss and forgetting of a campus card according to an embodiment of the present invention.
[0030] Such as figure 1 As shown, the transmitting circuit and receiving circuit installed on the campus card and the card sleeve both include a power supply, a wireless transceiver module, a controller, a buzzer, and an LED. The wireless transceiver module, the buzzer, and the LED are connected to the The controller is connected, the power supply supplies power to other modules in the circuit, the wireless transmitting module in the transmitting circuit is set to transmit mode, the wireless receiving module in the receiving circuit is set to receiving mode, and the transmitting module is The receiving module transmits a radio frequency signal. When the campus card and card sleeve exceed the set safe distance, the receiving module cannot receive the radio frequency signal, and the controller on the campus card and card sleeve simultaneously controls the buzzer to send an alarm signal.
[0031] Preferably, the present invention also includes an LED light. When the campus card and card sleeve are out of the safe range, the controller (MCU) controls the LED light to flash to remind the owner to pay attention.
[0032] Specifically, the present invention uses the 3V single-chip 89LE52 as the controller, and judges whether the object to be protected is within the safe range by detecting whether the wireless transceiver module can transmit and receive signals normally. When the distance between the sending and receiving modules is within the "safe range" (3-10m), the system works normally and the data transmission is normal; if it exceeds the safe range, the system cannot perform normal data transmission. At this time, the campus card and card sleeve The upper controller (MCU) will simultaneously control the buzzer to send out an alarm signal to remind the owner to pay attention.
[0033] The invention adopts a single power supply system, and the operating power of the single-chip microcomputer and the wireless module are both 3V, so the same power supply is used.
[0034] The working flow of this circuit is as follows: first power up the receiving circuit, make the receiving module in the receiving state, and wait for the data to arrive; then run the program on the single-chip microcomputer to transmit the data stored in advance in the single-chip register. If the distance between the transmitting module and the receiving module is within the "safe range", the receiving module will receive the signal within 1 ms and will not alarm. If it exceeds the "safety range", the receiving module will make the buzzer sound or the LED light flashes to alarm.
[0035] Refer below figure 2 The wireless transceiver module of the present invention is introduced in detail.
[0036] Such as figure 2 As shown, the wireless transceiver module of the present invention is an nRF24L01 radio frequency chip. nRF24L01 is a new single-chip radio frequency transceiver device, which works in the 2.4 GHz-2.5 GHz ISM frequency band. nRF24L01 has built-in frequency synthesizer, power amplifier, crystal oscillator, modulator and other functional modules, and incorporates enhanced ShockBurst technology, in which output power and communication channels can be configured through programs. nRF24L01 has low power consumption. When transmitting at -6 dBm, the working current is only 9 mA; when receiving, the working current is only 12.3 mA. Multiple low-power working modes (power-down mode and idle mode) make energy-saving design more convenient .
[0037] When nRF24L01 is used as a transmitting module to transmit data, first configure nRF24L01 to transmit mode, and then write the address and data into nRF24L01 buffer area by SPI interface according to the time sequence, then set CE to high level and keep it at least 10μs, and transmit data after a delay of 130μs; If the automatic response is turned on, the nRF24L01 will immediately enter the receiving mode after transmitting the data to receive the response signal. If a response is received, the communication is considered successful, TX_DS is set high, and TX_PLD is cleared from the transmit stack; if no response is received, the data is automatically retransmitted (automatic retransmission is enabled), if the number of retransmissions (ARC_CNT ) When the upper limit is reached, MAX_RT is set high, TX_PLD will not be cleared; when MAX_RT or TX_DS is set high, IRQ becomes low to notify the MCU. When the last transmission is successful, if CE is low, nRF24L01 enters idle mode 1; if there is data in the sending stack and CE is high, it enters the next transmission; if there is no data in the sending stack and CE is high, then it enters idle mode 2.
[0038] When nRF24L01 is used as a receiving module to receive data, first configure nRF24L01 to receive mode, and then delay 130μs to enter the receiving state and wait for the data to arrive. When the receiver detects a valid address and CRC, it stores the data packet in the receive stack, and at the same time the interrupt flag bit RX_DR is set high and the IRQ becomes low, so as to notify the MCU to fetch the data. If the automatic answer is turned on at this time, the receiver will enter the transmitting state and return the answer signal at the same time. When the final reception is successful, if CE goes low, nRF24L01 enters idle mode 1.
[0039] Fig. 3(a) is a schematic diagram of a flow of transmitting radio frequency signals by a transmitting circuit according to an embodiment of the present invention. As shown in Figure 3(a), after the transmitter circuit is powered on, the MCU 89LE52 is initialized, and the nRF24L01 also performs the initialization configuration subroutine, and then activates the nRF24L01 to transmit mode. The radio frequency signal transmission and reception distance of the wireless transceiver module of the present invention is adjustable. Yes, therefore, you can select the distance to send and receive radio frequency signals in nRF24L01. If the transmission is successful, nRF24L01 restores the default value of the register state and enters the next transmission.
[0040] Fig. 3(b) is a schematic diagram of a flow of receiving a radio frequency signal by a receiving circuit according to an embodiment of the present invention. As shown in Figure 3(b), after the receiving circuit is powered on, the MCU 89LE52 is initialized, and nRF24L01 also performs the initialization configuration subroutine, and then activates the nRF24L01 to receive mode. If the data reception fails, the controller controls the buzzer to sound. In order to send an alarm signal, according to another embodiment of the present invention, when the data transmission fails, the controller can also control LEDs and other flashing alarms. If the data is received successfully, nRF24L01 restores the default value of the register state and ends the data receiving process.
[0041] The nRF24L01 used in the present invention can turn on the automatic response mode. Therefore, when the nRF24L01 as the receiving module receives the radio frequency signal, it will send the response signal to the nRF24L01 as the transmitting module. When the radio frequency signal reception fails, the radio frequency signal transmission of the present invention Both the receiving end and the receiving end can detect the failure of data transmission. Therefore, the controllers in the sending end and the receiving end can control the buzzer or LED light to give an alarm, thereby reminding the owner of the campus card or the vicinity of the credit card machine Staff, help keep the lost campus card properly.
[0042] The above content is only the preferred embodiments of the present invention. For those of ordinary skill in the art, according to the ideas of the present invention, there will be changes in the specific implementation and the scope of application. limits.

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