CN112218064A

CN112218064A - Projector remote control system

Info

Publication number: CN112218064A
Application number: CN202011031843.XA
Authority: CN
Inventors: 望玥洋
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-27
Filing date: 2020-09-27
Publication date: 2021-01-12

Abstract

The invention discloses a remote control system of a projector, which comprises a singlechip (107), a wireless unit circuit (109) electrically connected with the singlechip (107), a second photoelectric indicating circuit (105) and a third photoelectric indicating circuit (106) which are used for the wireless unit circuit (109) to send and receive infrared remote sensing signals, and a power supply circuit for supplying power to the modules; the second photoelectric indication circuit (105) and the third photoelectric indication circuit (106) are respectively electrically connected with the wireless unit circuit (109); the wireless unit circuit (109) adopts an infrared remote sensing protocol; the power supply circuit consists of a 5V power supply circuit and a 3.3V power supply circuit, and supplies power to different parts in the control system respectively. The invention realizes the remote sending of the NEC infrared code through a wireless technology, and can realize the batch and individual control of each device through the preset independent NEC control code of the device, thereby realizing the intelligent management.

Description

Projector remote control system

Technical Field

The invention relates to the technical field of projection, in particular to a projector control system and a projector control method.

Background

With the scientific progress and the improvement of the living standard of people, the projector is widely applied to the production and the living of people. The projection display mode on the market is that a projector projects an image onto a projection screen, and the image or video projected onto the projection screen presents magnification of several times or tens of times under the condition of keeping definition.

Patent CN 109212875 a discloses a "projector control system and control method", which includes a main controller, a dynamic current adjusting module, a color wheel controller, a color wheel rotation feedback module, and a light source; the dynamic current regulation module comprises a DLP module, a light source controller and a power supply module; the color wheel rotating speed feedback module generates a feedback signal; the DLP module receives the feedback signal, receives the dynamic brightness information and sends processed dynamic brightness information and a control signal to the light source controller according to the feedback signal; and the light source controller controls the power supply module to turn on the power switch and output a corresponding current value according to the received processed dynamic brightness information and the control signal sent by the DLP module. The technical requirements for the identification and control of the infrared NEC codes are lacked in the scheme, and the control accuracy and effectiveness of the projector are influenced.

The projection curtain in the projector system on the market is divided into two kinds, one kind is the manual auto-lock curtain of portable tripod form, and one kind is the remote control curtain. If the manual self-locking curtain in the form of a portable tripod needs to be adjusted in the projection process, the curtain needs to be manually adjusted, so that the operation is complicated; for the remote control curtain, although the curtain is unfolded and folded without manual adjustment, the curtain needs to be controlled by remote control near the curtain; therefore, whether for a manual self-locking curtain or a remote control curtain, the control of the curtain is not intelligent enough. In addition, in a projection control system on the market at present, if working parameters such as projection intensity and lens steering of a projector need to be adjusted, the adjustment can only be manually performed generally, and when a projection environment changes, the adjustment needs to be performed for multiple times according to an actual projection effect, so that manpower is wasted, and the efficiency is low. Moreover, under the daily office and teaching environment, a plurality of projection devices are installed in independent rooms, manual on-off control and other control consume a large amount of manpower and time, and management is time-consuming and labor-consuming.

Disclosure of Invention

The invention aims to provide a remote control system of a projector, which realizes remote sending of NEC infrared codes, batch and individual control of each device and management intellectualization.

The invention provides a remote control system of a projector, which comprises a singlechip (107), a wireless unit circuit (109) electrically connected with the singlechip (107), a second photoelectric indication circuit (105) and a third photoelectric indication circuit (106) used for the wireless unit circuit (109) to send and receive infrared remote sensing signals, and a power supply circuit for supplying power to the modules; the second photoelectric indication circuit (105) and the third photoelectric indication circuit (106) are respectively electrically connected with the wireless unit circuit (109); the wireless unit circuit (109) adopts an infrared remote sensing protocol; and the power supply circuit is used for supplying power to different parts in the control system by a 5V power supply circuit and a 3.3V power supply circuit respectively.

Further, the 5V power supply circuit comprises a USB interface circuit (100) and a first photoelectric indication circuit (104) used for judging whether the USB interface circuit (100) is normally powered on, and the first photoelectric indication circuit (104) is electrically connected with the USB interface circuit (100).

Furthermore, the 3.3V circuit comprises a rectifying circuit (101) electrically connected with the USB interface circuit (100) and a low-voltage drop filter voltage stabilizing circuit (103) electrically connected with the rectifying circuit (101), and converts a 5V power supply into a 3.3V power supply to supply power to the wireless unit circuit (109).

Furthermore, the rectifying circuit (101) is Schottky barrier rectifying and adopts a PMEG4002EB.115 electronic element; the USB interface circuit (100) adopts MICRO-USB-BF-SP electronic components.

The schottky barrier refers to a metal-semiconductor interface having a rectifying characteristic as if a diode had the rectifying characteristic. The most important difference between schottky barrier (barrier) and PN junction is that it has a lower interface voltage and a depletion layer at the metal end. The rectifying properties are determined by the work function of the metal, the energy gap of the intrinsic semiconductor, and the doping type and concentration of the semiconductor. The schottky effect needs to be well known in the design of semiconductor devices to ensure that the schottky barrier is not accidentally created where an ohmic contact is needed, and can be applied where a device needs to approximate an ideal diode due to its low interface voltage. In circuit design, they are also used together with common diodes and transistors, whose main function is to protect other devices on the circuit with their lower interface voltage. Schottky Barrier carbon nanotube field Effect transistor FET the contact between the metal and the carbon nanotube is not ideal so the stacking fault causes a Schottky barrier, so this barrier can be used to make a Schottky diode or transistor.

The USB interface circuit (100) is MICRO-USB-BF-SP, belongs to MicroUSB series, and MicroUSB has the following characteristics: MicroUSB is a portable version of the USB2.0 standard, smaller than the MiniUSB interface, and Micro-USB is the next generation specification of Mini-USB, supporting OTG. Micro-USB connectors are smaller and space-saving than standard USB and Mini-USB connectors, and are unique in that they include a stainless steel housing, have a plug life and strength of up to 10000 times, and are designed with a blind-mate configuration. The Micro-USB standard supports the current OTG function of USB, namely, under the condition that a host (such as a personal computer) is not provided, the portable equipment can directly realize data transmission, is compatible with USB1.1 (low speed: 1.5Mb/s, full speed: 12Mb/s) and USB2.0 (high speed: 480Mb/s), and simultaneously provides data transmission and charging.

The blind-mate structural design refers to that the USB interface circuit (100) supports positive and negative plugging.

Further, the infrared remote sensing protocol is specifically an NEC protocol; the single chip microcomputer (107) adopts STC15W204S-35W electronic components.

The infrared signal relates to an infrared remote control protocol, and the signal needs to be modulated and demodulated in the process of sending and receiving the infrared signal. The NEC protocol is one of infrared remote control protocols, and the protocol includes a boot code, an address complement, a command code, and a command complement. NEC functional characteristics include: 1. the address code and the address code reversal and the command code reversal have the data verification function and enhance the accuracy of the result; 2. pulse distance modulation, modulating duty cycle; 3.a carrier frequency of 38 KHZ; 4. bit time is logic 0: 1.125ms or logic 1: 2.25 ms; 5. the transmitted signal is the inverse of the received signal. NEC protocol logic sending process: 1. when a key is pressed down, generating an interrupt function generated by entering INT0 at a falling edge, monitoring whether an IO port is at a high level or not after delaying, and waiting for the high level of 9ms to pass and waiting for the low level of 4.5ms to pass if the IO port is at the high level; 2. then receive the remaining 4 groups of 8-bit data, the remaining 4 groups receive a high level of 0.56ms first, and then a logic "0" signal if 1.12ms has elapsed and a low level, and then a logic "1" if 2.25ms has elapsed; 3. and finally, monitoring whether the received data code is the same as the data code, namely monitoring the accuracy of the received data.

Furthermore, the first photoelectric indicating circuit (104), the second photoelectric indicating circuit (105), the third photoelectric indicating circuit (106) and the like are all formed by connecting light emitting diodes and resistors in series, and the resistors are used for current limiting protection of the photoelectric indicating circuits.

Further, the low-voltage-drop filtering and voltage-stabilizing circuit (103) comprises an AMS1117-3.3 unit, an organic capacitor and an electrodeless capacitor, the organic capacitor and the electrodeless capacitor are connected in parallel and then divided into two groups which are respectively and electrically connected to the input end and the output end of the AMS1117-3.3 unit, the organic capacitor filters low-frequency alternating current signals, and the electrodeless capacitor filters high-frequency alternating current signals.

The active capacitance is a capacitance like electrolytic capacitance, which is a capacitance formed by two electrodes respectively formed by an anode aluminum foil and a cathode electrolyte, and a layer of aluminum oxide film generated on the anode aluminum foil is used as a dielectric medium. Due to this structure, it has polarity. When the active capacitance is normally connected, the alumina film is kept stable under the influence of an electrochemical reaction; when reverse connection is performed, the aluminum oxide layer becomes thin, so that the capacitor is easily broken down. The electrolytic capacitor must be kept in circuit with regard to polarity. The common capacitor is non-polar, and two electrolytic capacitors with anodes or cathodes oppositely connected in series can form a non-polar electrolytic capacitor.

The voltage drop voltage in the low-voltage drop voltage stabilizing circuit refers to the minimum value of the difference between the input voltage and the output voltage required by the voltage stabilizer to maintain the output voltage within 100mV above and below the rated value of the voltage stabilizer. LDO (low dropout) regulators with positive output voltage typically use power transistors as PNP. This transistor allows saturation so that the regulator can have a very low dropout voltage, typically around 200 mV. Compared with the conventional linear voltage regulator using the NPN composite power transistor, the voltage drop of the conventional linear voltage regulator is about 2V. The negative output LDO uses an NPN as its pass device, which operates in a similar mode as the PNP device of the positive output LDO. The CMOS power transistors are upgraded to provide the lowest drop-out voltage, the only voltage drop across the regulator being due to the ON resistance of the power supply device load current. This way only a few tens of millivolts will be generated in the voltage drop if the load is small. The low dropout voltage regulator circuit is a linear regulator that uses a transistor or FET operating in its linear region to subtract excess voltage from the applied input voltage to produce a regulated output voltage.

Further, the wireless unit circuit (109) is electrically connected to the single chip microcomputer (107) through a connector (108), and the connector (108) adopts 7731-818-02LF electronic components.

Further, the wireless unit circuit (109) comprises a touch key for sending a wireless transmission related instruction, an ESP8266 wireless module electrically connected to the touch key, a 2-channel level conversion module electrically connected to the ESP8266 wireless module, and an infrared serial port communication module electrically connected to the 2-channel level conversion module.

The ESP8266 wireless module is a serial-to-wireless module, is internally provided with a self-contained firmware, and is simple to operate. The ESP8266 wireless module group is used for leading out 6 pins, wherein four pins for communication are similar to USART pins of the single chip microcomputer. The connection mode of the ESP8266 module group and the STM32 singlechip is as follows:

monolithic computer terminal TXD (PA9) -ESP8266 RXD; single chip processor end RXD (PA10) - -ESP8166 TXD; and (4) the two are connected to the ground.

For the program part, a user sends an instruction to the wireless module through the USART, and the firmware program in the chip can perform corresponding operation according to the instruction set and give data feedback. Because of the operation of the character string command, the control command is relatively simple, and relatively speaking, the data analysis is slightly complicated.

(1) Initialization

The following is an initialization procedure, including wireless startup, determination of a communication mode, and establishment of UDP protocol communication, and then both the PC end and the mobile phone end in the local area network can communicate with them and can send instructions to them.

uart _ init (115200); v/Serial initialization to 9600

delay _ ms (1000); // set wireless name mode of operation

printf("AT+CWSAP＝\"LiMing\"，\"0123456789\",11,0\r\n")；

delay _ ms (50); setting a communication mode: using UDP network communication protocol

printf("AT+CIPSTART＝\"UDP\"，\"192.168.4.2\",5000,5000\r\n")；

delay_ms(50)；

(2) Data transmission (lower computer end)

The data transmission code refers to the lower course and transmits character string data, firstly, the number of the character string bits needs to be transmitted, then, the time is delayed, then, the character string is transmitted, and then, the time is delayed. If the original data is the character string, the original data only needs to be transmitted according to the above, namely, the transmission instruction of the first data in the process. Furthermore, if the transmitted data is variable, the variable of printf is required to be used for converting the character string, such as the second data in the process.

printf ("AT + CIPSEND ═ 1\ r \ n"); // number of bits of transmission string

delay_ms(1)；

printf ("D \ r \ n"); // sending a string

delay_ms(1)；

printf ("AT + CIPSEND ═ 4\ r \ n"); 4 bits for transmitting character string

delay_ms(1)；

printf ("% f \ r \ n", Battery _ All); // transmit variable% f floating point type

delay_ms(1)；

change＝5；

The data in the character string format is received by the upper computer end, and the data is extracted by an upper computer program and then is realized to the upper computer end.

(3) Data receiving (lower computer end)

The following is a routine code for data reception, which is to receive character string data, then extract the first character and the second character, determine the working mode, and select the mode of the main control chip. If the data information is received, only the flag bit of the first character needs to be changed, and then the lower computer carries out a distinguishing mode according to the flag bit.

The ESP8266 mainly involves the following aspects in terms of sending data to the server:

1. selecting a wireless application mode:

AT + CWMODE ═ 1.Station mode, 2.AP mode, 3.AP + Station mode.

2. The restart takes effect:

AT + RST, return value is OK

3. And (3) access routing:

AT + CWJAP is "ssid", which is the name of the router; password is the router password.

4. Connecting to a server:

AT + CIPSTART ═ TCP ","192.168.1.102", 8001. TCP is a communication protocol, and can also be UDP; 192.168.1.102 server address; 8001 is a server channel.

5. Enabling transparent transmission mode

AT+CIPMODE＝1；

The transparent transmission mode, namely SerialNet mode converts the local asynchronous serial port communication into network communication based on TCP/UDP protocol. The main purpose is to enable simple devices that communicate serially to communicate over a network without requiring any changes to be made to the devices. To this end, the SerialNet mode defines a series of relevant operating parameters that define the attributes required for network connectivity. When the DTU is operating in SerialNet mode, it operates as a router between the serial port of the device and the network. The SerialNet mode is different from a client or a server, when a client initiates a communication request and before data transmission between the two devices, a DTU must establish network connection with a remote service center, that is, when the client (such as a PLC) needs to perform data transmission with the data center, the client is firstly connected with a serial port of the DTU, and after entering the SerialNet mode, the DTU is automatically called to establish network connection with the server center device. After entering the SerialNet mode, the DTU can be used as a client mode or a server mode. The DTU working in the SerialNet mode automatically completes the conversion from the serial port to the network communication, and all data can be transmitted between the two devices in a two-way mode transparently.

The SerialNet mode is established by first defining all relevant parameters with an AT + I command, and then entering SerialNet mode with a special AT + I command. Once entering SerialNet mode, the DTU will not receive any AT + I command any more, and through the connection with the host serial port, the DTU focuses on processing the data of the local device serial port, and the DTU does not perform any processing (i.e. transparent transmission) on the data. In this mode, the auto baud rate does not work and a fixed baud rate must be set before entering SerialNet mode.

The SerialNet mode can be terminated by two methods:

a) by monitoring the data flow through three jumpers of k1, k2 and k3, various schemes can be realized through different combinations to trigger the reset mechanism.

b) Continuously inputting 3 + signs through a serial port with the interval within half second

Whenever one of the events occurs, the DTU will exit SerialNet mode and then restart, AT which point the DTU switches to command mode and can again respond to AT + I commands.

6. Transmitting data

AT + CIPSEND ═ len; data of a specified length is transmitted. Since the transmitted data needs to be in the necessary format, json format is used for communication, and therefore the data needs to be converted to json format before being uploaded.

Further, the light touch key adopts a k2-3.6 × 6.1_ SMD electronic component.

The light touch key is composed of an insert, a base, an elastic sheet, a button and a cover plate, wherein a layer of polyimide film is added on the elastic sheet of the waterproof light touch key. The light touch key has the advantages of small contact resistance load, high precision, diversified specifications and the like. The pins of the light touch key are in a group of two, when the light touch key is pressed, the four pins are conducted, and the fifth pin has a grounding effect.

One aspect of the technical effect brought by the technical scheme of the invention is that the NEC infrared code is remotely sent by a wireless technology, and each device can be controlled in batch and independently by a preset device independent NEC control code, so that management intellectualization is realized.

One aspect of the technical effect brought by the technical scheme of the invention is that the ESP8266 wireless module is used, the existing wireless can be converted into an infrared gateway and is electrically connected with an infrared serial port communication module, and a specific real-time method for the coding, modulation and demodulation functions of the infrared remote sensing NEC is known, so that the infrared remote sensing control function is realized.

Drawings

FIG. 1 is a circuit block diagram of a remote control system of a projector according to the present invention;

FIG. 2 is a schematic circuit diagram of a remote control system for a projector according to the present invention;

FIG. 3 is a diagram of a wireless circuit configuration of a remote control system of a projector according to the present invention;

FIG. 4 is a diagram of an infrared remote sensing system of a remote control system of a projector according to the present invention;

FIG. 5 is a timing diagram of an IR code capture by an oscilloscope in accordance with an embodiment of the present invention;

100, a USB interface circuit, 101, a rectifying circuit, 103, a low-voltage drop filter voltage stabilizing circuit, 104, a first photoelectric indicating circuit, 105, a second photoelectric indicating circuit, 106, a third photoelectric indicating circuit, 107, a single chip microcomputer, 108, a connector, 109, a wireless unit circuit, 110, an ESP8266 wireless module, 112, an infrared serial communication module, 111, a 2-way level conversion module, 113, a transmitting end, 114, a receiving end, 115, a keyboard matrix, 116, a code modulation module, 117, an LED infrared transmitter, 118, a photoelectric conversion amplifier, 119, a demodulation circuit, 120 and a decoding circuit.

Detailed Description

Example 1

The example mainly illustrates that the NEC infrared codes are remotely sent through a wireless technology, so that each device is controlled in batch and independently, and management intellectualization is realized.

A remote control system of a projector is shown in fig. 1 and fig. 2, and comprises a USB interface circuit 100, a rectifying circuit 101, a low-voltage drop filter voltage stabilizing circuit 103, a first photoelectric indicating circuit 104, a second photoelectric indicating circuit 105, a third photoelectric indicating circuit 106, a single chip 107, a connector 108 and a wireless unit circuit 109; the control system needs a 5V power supply to supply power to circuits electrically connected with the USB interface circuit 100, the rectifying circuit 101, the first photoelectric indicating circuit 104, the second photoelectric indicating circuit 105, the third photoelectric indicating circuit 106, the single chip microcomputer 107 and the like, and 5V voltage is supplied to the circuits electrically connected with the USB interface circuit 101, the rectifying circuit 101 is electrically connected with the low-voltage-drop filtering and voltage-stabilizing circuit 103, the 5V voltage is stabilized at 3.3V, and power supply voltage is supplied to the wireless unit circuit 109. The specific situation is as follows:

the USB interface circuit 100 is CN1 MICRO-USB-BF-5P in type, the 1 script +5V voltage is divided into A, B, C paths, and the A path is used for electrically connecting and supplying power for the first photoelectric indicating circuit 104 and the rectifying circuit 101; the B circuit supplies power for the second photoelectric indicating circuit 105 and the third photoelectric indicating circuit 106 and supplies power to a common capacitor C1, and the common capacitor C1 is connected to the ground; and the C path is electrically connected with the No. 2 script of the singlechip 107 for power supply. The No. 5 script of the USB interface circuit 100 is a ground terminal.

The first photoelectric indicating circuit 104 is formed by connecting a light emitting diode LED3(LED-0603R) and a resistor R9(1K ohm) in series, and is grounded through a resistor R9(1K ohm), so that the function of power indication is achieved once an external power supply is normally supplied.

The rectifier circuit 101 is D1 pmeg4002eb.115, and is divided into two terminals, namely a positive terminal and a negative terminal, the positive terminal is electrically connected with the script No. 1 of the USB interface circuit 100, and the negative terminal is electrically connected with the low-voltage-drop filter voltage regulator circuit 103.

The low-voltage drop filtering voltage stabilizing circuit 103 is U3 AMS1117-3.3 in model number, comprises scripts No. 1, No. 2 and No. 3 which are respectively a grounding end, an output end and an input end, and is electrically connected with the script No. 3 after an active capacitor C4(100uf) and a common capacitor C5(1.5uf) are connected in parallel; the active capacitance C3(100uf) and the common capacitance (1.5uf) are connected in parallel and then electrically connected with the No. 2 script; script 1 is grounded, resulting in a 3.3V supply voltage for the wireless unit 109.

The wireless unit circuit 109 is U1 ESP-12F (ESP8255MOD), and the 1 st script is reset and cleared, and the reset and clear circuit is specifically as follows: the 3.3V power supply voltage is electrically connected with a resistor R6(10K ohm), the resistor R6(10K ohm) is divided into two paths, and one path is electrically connected with the No. 1 script of the single chip microcomputer 107; the other path is electrically connected with the tact switch KEY2(K2-3.6 × 5.1_ SMD), the other end of the tact switch KEY2(K2-3.6 × 5.1_ SMD) is grounded, and a capacitor C2(0.1uf) is connected in parallel with the tact switch KEY2(K2-3.6 × 5.1_ SMD).

The wireless unit circuit 109 is U1 ESP-12F (ESP8255MOD), and the No. 3 pin enable bit is electrically connected by a resistor R5(10K ohm) connected in series with a 3.3V power voltage; script No. 8 is a supply voltage bit, fed by a 3.3V supply voltage.

The wireless unit circuit 109 has the model number U1 ESP-12F (ESP8255MOD), and the model 10 scripts GPIO15, MTDO, HSPICS, UARTO _ RTS; script 9 is grounded, and is connected in series with script 10 by resistor R4(1K), and resistor R4 is electrically connected to tact switch KEY1(K1-3.6 × 5.1_ SMD).

Scripts

11 and 12 are simultaneously electrically connected in series to the other end of tact switch KEY1(K1-3.6 x 5.1_ SMD), and the 3.3V supply voltage is electrically connected in series to resistor R3(10K ohms), which resistor R3(10K ohms) is electrically connected to

scripts

11 and 12 of wireless unit circuit 109.

The wireless unit circuit 109 is U1 ESP-12F (ESP8255MOD), scripts 15 and 16 of the wireless unit circuit are respectively connected with a resistor R8(100 ohms) and a resistor R7(100 ohms) in series, the resistor R7 and the resistor R8 are respectively electrically connected with the script No. 1 and the script No. 2 of the connector 108, and the script No. 1 and the script No. 2 of the connector 108 are respectively electrically connected with the script 5 and the script 6 of the singlechip 107(U2 STC15W 204S-35I). The wireless unit circuit 109 comprises a touch key, an ESP8266 wireless module, an infrared serial port communication module and a 2-way level conversion module. The ESP8266 wireless module is electrically connected with the 2-way level conversion module, the 2-way level conversion module is electrically connected with the infrared serial port communication module, and the wireless unit circuit 109 adopts an infrared remote sensing protocol and is an NEC protocol.

The model of the single chip microcomputer 107 is U2 STC15W204S-35I, the No. 2 script of the single chip microcomputer is connected with 5V power supply voltage, the No. 4 script of the single chip microcomputer is grounded, the No. 5 script and the No. 6 script of the single chip microcomputer are respectively and electrically connected with the No. 1 script and the No. 2 script of the connector 108, and the No. 7 script and the No. 8 script of the single chip microcomputer are respectively and electrically connected with the cathodes of light emitting diodes in the second photoelectric indicating circuit 105 and the third photoelectric indicating circuit 106.

The second photoelectric indicating circuit 105 is composed of a resistor R1(100 ohms) and an LED2(SIR-320GT3FP) which are connected in series, and the third photoelectric indicating circuit 106 is composed of a resistor R2(1K ohms) and an LED1(LED-0603_ R) which are connected in series.

Example 2

This embodiment explains how the ESP8266 wireless module realizes the function of converting wireless into an infrared gateway and the function of debugging the infrared serial port communication module, specifically as follows:

in this embodiment, as shown in fig. 3, an ESP8266 wireless module 110, an infrared serial communication module 112, and a 2-way level conversion module 111 are adopted. The infrared serial port communication module 112 omits serial port communication and infrared coding programs of the singlechip; the 2-path level conversion module 111 converts the 3.3V level of the ESP8266 wireless module 110 into the 5V level required by the infrared serial port communication module 112; the ESP8266 wireless module is provided with two serial ports, a serial port 0 is bidirectional and is generally used for communicating with the MCU, and a serial port 1 is only Tx and is used for displaying LOG.

The infrared serial port communication module 112 has the following functions of 1. having an NEC format infrared emission function; 2. the method has the NEC format infrared coding function; 3. an extension interface with an infrared emission head; 4. the device has a serial port communication function, and the communication level is TTL; 5. NEC infrared format device that can control 99%; 6. supporting NEC coding chips (typical coding chips such as uPD6121, uPD6122 and TC9012 and a plurality of compatible chip models such as PT2221, PT2222, SC6121, SC6122 and SC 9012); 7. the infrared wireless data communication and data transmission device can be used for infrared wireless data communication, data transmission, infrared control and other functions.

When encoding, the infrared signal corresponding to the encoding can be restored by sending an instruction according to a certain format and sending an instruction of 5 bytes through a serial port of a computer or a single chip microcomputer.

When decoding, it need not send any instruction, only need to pick up the receiving head of the remote control alignment module and press, at this moment, the serial port of the module outputs the infrared code.

When the remote control codes are obtained, the infrared serial port communication module is required to be connected to the USB-to-TTL module (voltage is 5V), the serial port debugging assistant is opened, the infrared remote control keys of the household appliance are pressed, and the infrared codes of the keys are obtained and recorded.

For the infrared serial port communication module 112, firstly, the pins are as follows:

GND

RXD

TXD

5V

the pins are simple, the USB-TTL is adopted to connect with the infrared serial port communication module 112, and then the serial port debugging assistant on the PC is used to complete the verification of the module. The following table is used for connection:

NEC infrared receiving and transmitting module	USB-TTL
		GND	GND
RXD	TXD
		TXD	RXD
5V	5V

In the debugging process, the infrared serial port communication module 112 is directly connected with the USB-TTL only without involving a single chip microcomputer, a serial port debugging assistant is started, the default set baud rate is 9600bps, and the serial port debugging assistant is connected with the single chip microcomputer conveniently. But the baud rate can also be modified, such as command:

F1	infrared emission state
		F2	Entering the state of modifying serial port communication address
F3	Entering a modified baud rate state

And modifying the corresponding baud rate or modifying the state value of the serial port communication address by debugging assistant software to monitor and check the result. For example, the modified baud rate is 9600bps (corresponding to sequence number 02), the corresponding command is { a1, F3,02,00,00}, and the modified baud rate returns to the F3 interface after being successfully modified.

Example 3

The embodiment describes a specific real-time method for functions of infrared remote sensing NEC encoding, modulation and demodulation, which comprises the following steps:

as shown in fig. 4, the infrared remote sensing system relates to infrared NEC encoding, debugging and demodulation, and specifically includes a transmitting terminal 113 and a receiving terminal 114, wherein application encoding and application decoding employ an application specific integrated circuit chip for control operation. Wherein the transmitting end 113 comprises a keyboard matrix 115, a code modulation 116, an LED infrared transmitter 117; the receiving terminal 114 includes a photoelectric conversion amplifier 118, a demodulation circuit 119, and a decoding circuit 120.

Specifically, after an input signal passes through a keyboard matrix 115 and code modulation 116 at a transmitting end 113, the input signal enters an infrared generator 117, and the infrared generator 117 sends an infrared signal; after receiving the infrared signal at the receiving end 113, the infrared signal is amplified by the photoelectric conversion amplifier 118 and then restored to a signal. The infrared remote control transmits data in a modulation mode, namely, the data and a carrier wave with a certain frequency are subjected to AND operation, so that the transmission efficiency can be improved, the power consumption of a power supply can be reduced, and the modulated carrier wave frequency is 38kHz, and the square wave of the duty ratio 1/3 is obtained. The crystal oscillator is divided by an integer at the transmitting end 113, and the division coefficient is 12, so that 55 kHz/12 kHz is approximately equal to 37.9kHz and 38kHz is approximately equal to.

Infrared rays are emitted through an infrared Light Emitting Diode (LED), the internal structure of the infrared light emitting diode (infrared emitting tube) is basically the same as that of a common light emitting diode, the material is different from that of the common light emitting diode, and when a certain voltage is applied to both ends of the infrared emitting tube, infrared rays are emitted instead of visible light. The infrared receiving circuit in the infrared signal transceiving system is usually integrated into one component to form an integrated infrared receiving head. The integrated infrared receiving head internal circuit comprises an infrared monitoring diode, an amplifier, an amplitude limiter, a band-pass filter, an integrating circuit and a comparator.

When the infrared monitor diode detects infrared signal, it sends the signal to amplifier and limiter, which controls the pulse amplitude at a certain level. The alternating current signal enters a band-pass filter to form a load wave of 30-60 khz, and then enters a comparator through a demodulation circuit and an integration circuit, and the comparator outputs high and low levels to restore the signal waveform of a transmitting end. Note that the high and low levels of the output and the transmitting end are inverted, which is intended to improve the sensitivity of reception.

Example 4

The embodiment explains a specific design idea and an implementation scheme of an infrared remote controller which is based on a single chip microcomputer and can learn and store existing infrared emission equipment. The specific situation is as follows:

it is first necessary to specify what hardware devices are required to support the remote control for the function.

1.3.3V and 5V power supply modules for supplying power to the system module and the singlechip

And the 2.5V infrared receiving head is used for receiving infrared rays of other infrared remote control equipment, converting the infrared rays into electric signals and sending the electric signals to the MCU.

The MCU is connected with the temperature sensor through an I2C bus. The I2C bus occupies 2 MCU input/output lines, and communication between the two is completely accomplished by software. The address of the temperature sensor can be set by 2 address pins, so that 8 sensors can be simultaneously connected to one I2C bus. When the MCU needs to access the sensor, it first sends out an 8-bit register pointer and then sends out the address of the sensor (7-bit address, low order is WR signal). There are 3 registers available to the MCU in the sensor and an 8-bit register pointer is used to determine which register the MCU will use. To read the contents of the sensor measurement register, the MCU must first transmit the sensor address and the register pointer. The measurement register may be read by the MCU by issuing an enable signal, followed by the sensor address, and then setting the RD/WR pin high.

After the MCU reads the sensor measurements, it then performs a conversion and displays the result on the LCD. The whole processing process comprises the steps of judging the sign of a display result, converting binary codes into BCD codes, and transmitting data to a relevant register of the LCD. After the data processing is finished and the result is displayed, the MCU sends a single step instruction to the sensor. The single step command causes the sensor to initiate a temperature test and then automatically enter a wait mode until the analog to digital conversion is completed. After the MCU sends a single step instruction, the LPM3 mode is entered, at this time, the MCU system clock continues working, and a timed interrupt is generated to wake up the CPU. The timing can be adjusted in length by programming to suit the needs of a particular application.

And 3, the STC15W204S-35W singlechip is a singlechip with SPI, timer, PWM and external interrupt functions, the MCU is used for receiving the transmitted electric signals, analyzing the electric signals into digital codes, storing the digital codes into an array, and then storing the array into an external FLASH, thereby realizing the receiving and storing functions.

The SPI is a serial peripheral interface, is a high-speed, full-duplex and synchronous communication bus, only four lines are occupied on pins of a chip, the pins of the chip are saved, space is saved in the layout of a PCB, and convenience is provided.

The Pulse Width Modulation (PWM) is a method of digitally encoding the level of an analog signal. Through the use of high resolution counters, the duty cycle of the square wave is modulated to encode the level of a particular analog signal. The PWM signal is still digital because at any given time, the full magnitude dc supply is either completely present (ON) or completely absent (OFF). The voltage or current source is applied to the analog load in a repetitive pulse train of ON (ON) or OFF (OFF). The on-time is when the dc supply is applied to the load and the off-time is when the supply is disconnected. Any analog value can be encoded using PWM as long as the bandwidth is sufficient. Most loads, whether inductive or capacitive, require a modulation frequency above 10Hz, typically between 1kHz and 200 kHz. Many microcontrollers contain a PWM controller within them.

And 4, a W25Q64 chip which is a FLASH memory chip, the memory space is 8Mbytes, and the communication mode with the MCU is SPI. The MCU receives the infrared coding information, stores the infrared coding information into the FLASH through the communication between the SPI and the MCU, and extracts the infrared coding information from the FLSAH when the infrared coding information needs to be transmitted.

5. And the PWM pin of the MCU controls the infrared emitting diode to transmit the infrared code. And the carrier wave of the infrared ray of 38KHZ is realized under the action of PWM. And extracting infrared coding information from the FLASH, and controlling whether to transmit carrier waves according to the coding time to realize the transmission of the infrared coding information.

And secondly, the hardware design aspect is carried out.

In this embodiment, the remote controller device supplies power to the 5V power supply, and the 5V power supply supplies power to the infrared receiving head and the input end of the ASM1117 module. The ASM1117 module regulates 5V to 3.3V to supply power to the W25Q64 chip, the STC15W204S-35W single chip microcomputer, the OLED display screen and the NRF24L01 wireless module. The STM32 single chip microcomputer sends out infrared signal timing level to drive the NPN triode infrared transmitting tube. And the infrared receiving head receives the infrared code and stores the infrared code into a W25Q64 memory chip. The stored codes can be transmitted through the keys by selecting settings through the interface of the matrix keys and the OLED screen.

Again, the software design aspect is performed.

The main function initializes a hardware SPI drive, writes and reads data of a W25Q64 external FLASH through the hardware SPI, configures a timer 1 to be in a 5 millisecond timed interrupt mode, configures a timer 4 to be in a1 second timed interrupt mode, configures a timer 2 to be used as a PWM output to be used as a carrier wave for generating 38KHZ infrared emission, and configures a timer 3 to be used as a time count, calculates the time of received infrared codes, initializes the mode of an OLED display screen, configures the mode of used IO and configures the mode of receiving the external interrupt of the infrared codes. The main cycle displays the working mode of the remote controller, stores the content, judges the mode of the infrared remote controller changed by the key, and further judges which group of infrared codes in the transmitting storage area.

And finally, analyzing the infrared coding time sequence. As shown in fig. 5, the infrared code captured by the oscilloscope is the remote controller designed in this embodiment, where a high level indicates that the infrared transmitter does not transmit the infrared code of the 38KHZ carrier wave, and a low level indicates that the transmitter transmits the carrier wave. The time sequence of the infrared code can be analyzed by judging the time of high and low levels.

Claims

1. The remote control system of the projector is characterized by comprising a single chip microcomputer (107), a wireless unit circuit (109) electrically connected with the single chip microcomputer (107), a second photoelectric indication circuit (105) and a third photoelectric indication circuit (106) which are used for the wireless unit circuit (109) to send and receive infrared remote sensing signals, and a power supply circuit for supplying power to the modules; the second photoelectric indication circuit (105) and the third photoelectric indication circuit (106) are respectively electrically connected with the wireless unit circuit (109); the wireless unit circuit (109) adopts an infrared remote sensing protocol; the power supply circuit consists of a 5V power supply circuit and a 3.3V power supply circuit, and supplies power to different parts in the control system respectively.

2. The projector remote control system according to claim 1, wherein: the 5V power supply circuit comprises a USB interface circuit (100) and a first photoelectric indicating circuit (104) used for judging whether the USB interface circuit (100) is normally powered on, and the first photoelectric indicating circuit (104) is electrically connected with the USB interface circuit (100).

3. The projector remote control system according to claim 1, wherein: the 3.3V circuit comprises a rectifying circuit (101) electrically connected with the USB interface circuit (100) and a low-voltage-drop filter voltage stabilizing circuit (103) electrically connected with the rectifying circuit (101), 5V power voltage is converted into 3.3V power voltage, and the 3.3V power voltage supplies power for the wireless unit circuit (109).

4. A projector remote control system according to claim 3, wherein: the rectifying circuit (101) is Schottky barrier rectifying and has the model number PMEG4002EB.115; the USB interface circuit (100) is a MICRO-USB-BF-SP series.

5. The projector remote control system according to claim 1, wherein: the infrared remote sensing protocol is specifically an NEC protocol; the single chip microcomputer (107) is of STC15W204S series.

6. The projector remote control system according to claim 1, wherein: the first photoelectric indicating circuit (104), the second photoelectric indicating circuit (105), the third photoelectric indicating circuit (106) and the like are all formed by connecting light emitting diodes and resistors in series.

7. The remote control system of claim 1, wherein said low drop filter voltage regulator circuit (103) is comprised of an AMS1117-3.3 unit, a polar capacitor and a non-polar capacitor, wherein said AMS1117-3.3 unit comprises an input terminal, an output terminal and a ground terminal; the organic capacitor and the electrodeless capacitor are connected in parallel and then divided into two groups which are respectively electrically connected with the input end and the output end of the AMS1117-3.3 unit, and the grounding end of the AMS1117-3.3 unit is grounded.

8. A projector remote control system as claimed in claim 1, wherein said wireless unit circuit (109) is electrically connected to said one-chip microcomputer (107) through a connector (108).

9. The projector remote control system according to claim 7, wherein: the wireless unit circuit (109) comprises a touch key for sending wireless transmission related instructions, an ESP8266 wireless module electrically connected with the touch key, a 2-channel level conversion module electrically connected with the ESP8266 wireless module, and an infrared serial port communication module electrically connected with the 2-channel level conversion module.

10. A projector remote control system according to claim 9, wherein: the light touch key comprises a light touch key1 and a light touch key2, and the light touch key1 is electrically connected with the single chip microcomputer (107) after being connected with the common capacitor in parallel; the light touch key2 is connected with the resistor in series and then is electrically connected with the singlechip (107).