CN102855733A - 800-MHz (megahertz) digital wireless baby monitor - Google Patents

Abstract

The invention discloses an 800-MHz digital wireless baby monitor. The 800-MHz digital wireless baby monitor comprises a transmitter and a receiver, wherein the transmitter comprises a transmitter housing and a PCB (Printed Circuit Board) printed circuit board assembly arranged in the transmitter housing, the receiver comprises a receiving housing and the PCB printed circuit board assembly arranged in the receiving housing, and the PCB printed circuit board assembly comprises a radio frequency amplifying circuit, a DSP (Digital Signal Processor) digital signal processor, an audio frequency amplifying circuit, a temperature detection circuit and a smoke warning detection circuit. According to the 800-MHz digital wireless baby monitor, an 800-MHz frequency range is adopted, and a frequency hopping spread spectrum technique and a half-duplex working manner are used, so that the anti-jamming capability is strong; as a DSP digital filter is adopted, the tone quality is clear, and a reliable communication distance in an empty region can reach up to 600 meters; and the design is simple, the material cost and the production cost are lowered, and the output is improved.

Description

800MHz digital radio baby monitor

Technical field

The present invention relates to the 800MHz digital radio baby monitor that wireless family safety protection technique field, particularly a kind of communication distance are far away, smog, environment temperature are hanged down and can be detected and show in radiation.

Background technology

Baby monitor, translator of English is Baby Monitor, belongs to the wireless family security protection system, is comprised of care device (claiming that also the baby holds) and display (claiming that also father and mother hold) two parts, in baby's room, place care device, namely can guard at any time by display baby's safety.Baby monitor is as a kind of home-use security product, this product utilization monitoring end provides real-time supervision to every act and every move every word and action of baby, the result who monitors sends on guardian's control end equipment on hand by the radiowave of simulating signal or digital signal, and to be reduced into video or audio frequency.By using baby monitor, father and mother or guardian no longer need to wait for the behavior that can recognize by the side of them baby or child with keeping close, and can discover and process immediately when abnormal conditions occur.Baby's audiomonitor is not only the daily life nursing materials of infant's the best, also looks after the good assistant of old man and patient's indispensability.On the history of baby monitor industry, people adopt the baby monitor of Analog Circuit Design previously, mainly exist following problem (1) to adopt CTCSS or DCS code encoding/decoding mode, easily analyse password, and confidentiality is poor.(2) circuit is complicated, and components and parts are many, and production cost and failure rate are high.(3) can only adopt the single-simplex operation pattern, if adopt half-duplex mode of operation technical difficulty large, cost is very high.(4) function is simple, is difficult to satisfy the high-end customer needs.(5) frequency is few, is vulnerable to mobile phone and the interference of other communication apparatus.(6) volume is large.

2.4GHz wireless technology is a kind of short range wireless transmission technology, for increasing income.2.4GHz the working frequency range that refers to, 2.4GHz be the radio band that the whole world discloses general use ISM(Industry Science Medicine), under the 2.4GHz frequency range, work and to obtain larger usable range and stronger antijamming capability, development along with wireless communication technique, 2.4GHz wireless technology is widely used in baby monitor at present, although adopt the DSP(digital signal processor with the baby monitor of 2.4GHz design) technology.But have following problem: (1) emissive power is large, radiation is high, and long-time emission has certain impact to the baby.(2) communication distance is short, less than 300 meters, has limited range of application.

Summary of the invention

The present invention proposes for the shortcoming that overcomes above prior art existence, and it is strong that its technical matters that solves provides a kind of antijamming capability, sound clarity, the 800MHz digital radio baby monitor of long transmission distance.

For this reason, the invention provides a kind of 800MHz digital radio baby monitor, comprise transmitter and receiver, transmitter comprises the emission casing and places the interior PCB printed circuit-board assembly of emission casing, receiver comprises that receiving casing receives the interior PCB printed circuit-board assembly of casing with placing, and it is characterized in that: described emission casing is provided with emission LCD liquid crystal display, smog alarm socket, pairing key, temperature sensor; Described reception casing is provided with transmitter communication pilot lamp, receives LCD liquid crystal display, radiationless button; Described PCB printed circuit-board assembly comprise radio frequency amplifying circuit, DSP digital signal processor and be used for the tiny signal of input end zoom into desired signal audio amplifier circuit, be used for temperature sensing circuit that baby's environment temperature detects, be used for the smog alarm testing circuit that baby's ETS concentration detects.

As the present invention is further improved, described emission LCD liquid crystal display displaying contents comprises radiationless pointing character, pairing character.Emission LCD liquid crystal display displaying contents comprises that also transmitter acoustic control, horn volume show.

As the present invention is further improved, described reception LCD liquid crystal display displaying contents comprises radiationless pointing character, smog alarm pointing character, baby head picture collection of letters pointing character, pairing character.Receive LCD liquid crystal display displaying contents and comprise that also receiving sound, reception environment temperature, receiver vibration, the low electricity of battery and charged state, horn volume shows.

As the present invention is further improved, described baby head picture collection of letters pointing character comprises sleep pattern, the pattern of crying and screaming, painful pattern.

As the present invention is further improved, described radio frequency amplifying circuit comprises for the rf chip of radio frequency reception and emission, is used for the low-pass filter that reception is launched the transmitting-receiving conversion chip of switching, is used for the filtering high frequency.Micro-control unit MCU is packaged into buffer memory after receiving audio digital signals, when full 20 bags, just launch by rf chip, emission switch is closed in the rf chip control transceiver toggle switch, and radiofrequency signal is by low-pass filter, and the filtering HFS is launched.

As preferentially, described rf chip is high integration, low-power consumption, the radio transmitting and receiving chip of multiband.Its operating voltage is 1.9-3.6V, and inside comprises power amplifier, voltage controlled oscillator, High Amplifier Circuit, mixting circuit, mould/number conversion circuit and DLC (digital logic circuit).Chip in use required outer member seldom only needs 1 crystal, and several electric capacity and inductance just can form a highly reliable receive-transmit system, simplicity of design, and cost is low.When baud rate was 2kbps, receiving sensitivity reached-117dBm.When baud rate was 70kbps, receiving sensitivity reached-102dBm.Splendid link-quality can be provided, when enlarging communication context, power consumption be down to minimum.Minimum filtering bandwidth reaches 8KHz, has splendid frequency selectivity, and the peak power output when not adding power amplifier in frequency range can reach 20dBm.When baud rate was 2kbps, transmission range can reach 2KM farthest.When baud rate was 70kbps, reliable voice communication distance can reach more than 600 meters farthest.

As the present invention is further improved, described DSP digital signal processor comprises for the audio coder ﹠ decoder (codec) of microphone preamplifier, programmable filter, audio amplitude adjustment register and voice mould/number conversion and D/A, is used for obtaining enough note amplifiers of required sound signal.Voice signal is inputted by microphone, through difference input mode to the built-in preposition filtering and amplifying circuit of audio coder ﹠ decoder (codec) voice signal is amplified and filtering.Can come by the audio level register enlargement factor of selective amplifier, pass through again programmable filter to sound signal filtering.Then voice signal is compressed, analog signal conversion is become digital signal, from TX DT port transmission vocoded data to micro-control unit MCU.Micro-control unit MCU receives the speech data of radio-frequency module input, enters the chip decompress(ion) through RX DT mouth, converts digital signal to simulating signal.To sound signal filtering, come the enlargement factor of selective amplifier through programmable filter by the audio level register.Sound signal is amplified signal through note amplifier, and is exported from loudspeaker from the output of AF OUT mouth.

Further, described audio coder ﹠ decoder (codec) inside comprises that microphone preamplifier, programmable filter, audio amplitude adjust register and voice mould/number conversion and D/A.Audio coder ﹠ decoder (codec) has the full duplex codec functions, has the bit error rate low, low-power consumption, working current 1.9mA.This element has the configurable mode of operation of user and algorithm, therefore can be according to specifically being used for selecting best transfer rate and speech quality, can make application system development person remove the process of forward direction error code correction, formulation related protocol and algorithm from, greatly alleviate the burden of software programming work and the realization difficulty of system, thereby saved the cycle of system development.

The invention has the beneficial effects as follows: adopt the 800MHz frequency range, use frequency hop spread spectrum (AFA+LBT), antijamming capability is strong, and voice are realized baby and mommy's half duplex communication by wireless transmission; Adopt the DSP digital filter, filter out background noise, sound clarity; The baby holds emissive power to hold distance automatically to regulate with the mommy, and minute 13dBm, 16dBm and 20dBm third gear reduce radio-frequency radiation to greatest extent on baby's impact.Telecommunication, spacious regional reliable communicating distance can reach more than 600 meters; Can realize at 1 o'clock to pairing in 3 o'clock and communication, namely 1 mommy's machine is with the communication of 3 baby's machines; Can detect and smog alarm detection and demonstration and warning baby's environment temperature.

Description of drawings

Fig. 1 is the left view of 800MHz digital radio baby monitor transmitter of the present invention;

Fig. 2 is the front view of 800MHz digital radio baby monitor transmitter of the present invention;

Fig. 3 is the right view of 800MHz digital radio baby monitor transmitter of the present invention;

Fig. 4 is the right view of 800MHz digital radio baby monitor transmitter of the present invention;

Fig. 5 is the rear view of 800MHz digital radio baby monitor receiver of the present invention;

Fig. 6 is the front view of 800MHz digital radio baby monitor receiver of the present invention;

Fig. 7 is the right view of 800MHz digital radio baby monitor receiver of the present invention;

Fig. 8 is 800MHz digital radio baby monitor emission LCD liquid crystal display schematic diagram of the present invention;

Fig. 9 is that 800MHz digital radio baby monitor of the present invention receives LCD liquid crystal display schematic diagram;

Figure 10 is 800MHz digital radio baby monitor baby head picture collection of letters pointing character exploded view of the present invention;

Figure 11 is 800MHz digital radio baby monitor PCB printed circuit-board assembly circuit theory diagrams of the present invention;

Figure 12 is 800MHz digital radio baby monitor radio frequency amplifying circuit figure of the present invention;

Figure 13 is 800MHz digital radio baby monitor rf chip schematic diagram of the present invention;

Figure 14 is 800MHz digital radio baby monitor DSP digital signal processor of the present invention and audio amplifier circuit figure;

Figure 15 is 800MHz digital radio baby monitor DSP DSP chip schematic diagram of the present invention;

Figure 16 is 800MHz digital radio baby monitor temperature sensing circuit of the present invention and smog alarm testing circuit figure;

Embodiment

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described in further detail, the below omits the description to basic circuit and components and parts, just describes around innovative point of the present invention.

Shown in Fig. 1,3,5,7, a kind of 800MHz digital radio baby monitor, transmitter and receiver, transmitter comprise to be launchedcasing 1 and places the PCB printed circuit-board assembly 6 of launching in thecasing 1, and receiver comprises that receivingcasing 2 receives the interior PCB printed circuit-board assembly 6 of casing with placing.

Shown in Fig. 1,2,3,4, the front ofemission casing 1 is provided with emission LCDliquid crystal display 11, left surface and is provided with thatsmog alarm socket 12, right edge are established pairing key 13, the back side is provided withtemperature sensor 14, also compriseslower key 15,MODE key 16,upper key 17,microphone 18,loudspeaker 19, night-light 120, night-light control 121, power supply and VOX push button 122, externalelectric supply socket 123 on theemission casing 1.

Shown in Fig. 5,6,7, receivecasing 2 positive tops be provided with transmittercommunication pilot lamp 21, positive middle part be provided with receive LCDliquid crystal display 22, right edge is provided withradiationless button 23, receive on thecasing 2 also to compriselower key 24,MODE key 25,upper key 26,microphone 27,loudspeaker 28,PTT button 29,peripheral earphone socket 230, power supply andvibration push button 231, externalelectric supply socket 232.

As shown in Figure 8, described emission LCDliquid crystal display 11 displaying contents compriseradiationless pointing character 31, pairing character 32.Emission LCDliquid crystal display 11 displaying contents also comprise transmitteracoustic control 33,horn volume 34, andlaunch environment temperature 35 shows.

As shown in Figure 9, described reception LCDliquid crystal display 22 displaying contents comprise radiationless pointingcharacter 41, smogalarm pointing character 42, baby head picture collection ofletters pointing character 43, pairing character 44.Receive LCDliquid crystal display 22 displaying contents and also comprisereception sound size 45,reception environment temperature 46,receiver vibration 47, the low electricity of battery andcharged state 48,6 grades ofadjustings 49 of horn volume.

As shown in figure 10, described baby head picture collection ofletters pointing character 43 comprisessleep pattern 51, thepattern 52 of crying and screaming,painful pattern 53.

As shown in figure 11, PCB printed circuit-board assembly 6 comprises radio frequency amplifying circuit, DSP digital signal processor and audio amplifier circuit, temperature sensing circuit and smog alarm testing circuit.

The 800MHz digital radio baby monitor course of work of the present invention is as follows:

Shown in Figure 12,13, described radio frequency amplifying circuit comprises rf chip TW3321, transmitting-receiving conversion chip, low-pass filter.Micro-control unit MCU is packaged into buffer memory after receiving audio digital signals, when full 20 bags, just launch by rf chip, emission switch closure in the change-over switch is received/is sent out in rf chip control, and radiofrequency signal is by low-pass filter, and the filtering HFS is launched.Rf chip TW3321 operating voltage is 1.9-3.6V, there is power amplifier inside, wakes timer up, transmit and receive data FIFO and the configurable GPIO of digital modems, 64 bytes, required outer member is that the crystal of 1 20MHz and C5, C6, C7 electric capacity, L3, L4, L5 inductance, R2 resistance form a highly reliable emission coefficient in use, forms a highly reliable receiving system with C8, C9 electric capacity and L7 inductance.Simplicity of design, and cost is low.When baud rate was 2kbps, receiving sensitivity reached-117dBm.When baud rate was 70kbps, receiving sensitivity reached-102dBm.Splendid link-quality can be provided, when enlarging communication context, power consumption be down to minimum.Minimum filtering bandwidth reaches 8KHz, has splendid frequency selectivity, and the peak power output when not adding power amplifier in frequency range can reach 20dBm.When baud rate was 2kbps, transmission range can reach 2KM farthest.When baud rate was 70kbps, reliable voice communication distance can reach more than 600 meters farthest.

As shown in figure 14, described DSP digital signal processor comprises audio coder ﹠ decoder (codec), the note amplifier of microphone preamplifier, programmable filter, audio amplitude adjustment register and voice mould/number conversion and D/A.Voice signal is inputted by microphone,, voice signal is amplified through the built-in chip type prime amplifier to phonetic codec chip MIC+ and MIC-input through the difference input mode.Can come by the audio level register enlargement factor of selective amplifier, pass through again programmable filter to sound signal filtering.Then voice signal is compressed, analog signal conversion is become digital signal, from TX DT port transmission vocoded data to micro-control unit MCU.Micro-control unit MCU receives the speech data of radio-frequency module input, enters the chip decompress(ion) through RX DT mouth, converts digital signal to simulating signal.To sound signal filtering, come the enlargement factor of selective amplifier through programmable filter by the audio level register.Sound signal is amplified signal through note amplifier, and is exported from loudspeaker from the output of AF OUT mouth.

As shown in figure 15, described audio coder ﹠ decoder (codec) is TW3326, and TW3326 inside comprises microphone preamplifier, programmable filter, audio amplitude adjustment register and voice mould/number conversion and D/A.Audio coder ﹠ decoder (codec) TW3326 has the full duplex codec functions, has the bit error rate low, low-power consumption, working current 1.9mA.This element has the configurable mode of operation of user and algorithm, therefore can be according to specifically being used for selecting best transfer rate and speech quality.It provides the sample frequency from 16～128kbps, and sampling clock can be selected by the outside and provide or inner the generation.Inner integrated digital scrambler can strengthen the security of communication to a certain extent, and reduces the probability that irregular continuous " 1 " or " 0 " occurs, and speech detector then can be used for supporting the saving of power supply power consumption.

As shown in figure 16, resistance T1 value changes along with detecting baby's variation of ambient temperature in the temperature sensor, and micro-control unit MCU P5.0 mouth read-out voltage value calculates the resistance value of resistance T1.Compare with measuring resistance T1 value, calculate baby's environment temperature; When smoke alarm detects baby's environment certain density smog is arranged, by wireless launcher BT-100, send alerting signal with the 433MHz frequency.When the ANT1 antenna is received the 433MHz radiofrequency signal, through the low pass filter filters out HFS, input to radio-frequency module and amplify.Signal is by radio-frequency module SDN mouth output, when micro-control unit MCU detects when being the smog alarm signal, sends warning byloudspeaker 28.

When wishing that baby's machine is in without the radio-frequency radiation state, select by receiver button 23.Receive LCDliquid crystal display 22 this moment and show theradiationless character 31 of demonstration in radiationless pointingcharacter 41 and the emission LCDliquid crystal display 11; When receiver is received the smog alarm signal, receive LCDliquid crystal display 22 and show smogalarm pointing character 42; When the receiver stand-by state, receiver LCDliquid crystal display 22 displaying contents aresleep pattern 51 when baby's peace and quiet or sleep state, receiver LCDliquid crystal display 22 Alternation Display go out to cry andscream pattern 52 andpainful pattern 53 when the baby makes a lot of noise or cries and screams; Receiver LCDliquid crystal display 22 has 7 grades of the sound of reception sizes to changecharacter 45,46 demonstrations of reception environment temperature,receiver vibration 47 promptings, the low electricity of battery andcharged state 48 indications, 6 grades of adjustings of horn volume, 49 Presentation Functions simultaneously.Emission LCDliquid crystal display 11 displaying contents comprise radiationless pointingcharacter 31,pairing character 32,6 grades ofadjustable characters 33 of transmitter sound controling sensitivity, 6 grades ofadjustable characters 34 of horn volume.

When in a receiver and three transmitters one press button 13 among Fig. 3 when matching, push button 122 is pushed the upper end to simultaneously, the P character that this moment, Fig. 8 launched expressionlaunch environment temperature 35 in the LCDliquid crystal display 11 flashes.This moment, transmitter was in the pairing state, and same method makes receiver also be in the pairing state.Select which transmitter byupper key 17,lower key 15 among Fig. 2, pressMODE key 16 and confirm.Press againMODE key 16 and match, if the successful matching transmitter send " too " sound, the character P of expressionlaunch environment temperature 35 stops to flash among this moment Fig. 8.Transmitter and receiver character P stops flicker, andreceiver 44 characters show and which platform transmitter matches, and gives by that analogy other 2 transmitters pairing.

When a receiver and three transmitters were worked simultaneously, receiver carried out periodic duty in 30 seconds-30 seconds-30 seconds according to receiving every transmitter.When receiving transmitter signal, the machine of penetratingcommunication pilot lamp 21 corresponding among Fig. 6 glimmers, and communication finishes, and pilot lamp extinguishes.

Adopt 800MHz numeral baby monitor output power low (less than 25mW), communication distance (greater than 600 meters) far away, its unique outlook, deeply being subjected to all over the world, the user likes.

Claims (8)

1. a 800MHz digital radio baby monitor comprises transmitter and receiver,Transmitter comprises to be launched casing and places the interior PCB printed circuit-board assembly of emission casing, and receiver comprises the reception casing and places the PCB printed circuit-board assembly that receives in the casing,It is characterized in that: described emission casing is provided with emission LCD liquid crystal display, smog alarm socket, pairing key, temperature sensor; Described reception casing is provided with transmitter communication pilot lamp, receives LCD liquid crystal display, radiationless button; Described PCB printed circuit-board assembly comprises radio frequency amplifying circuit, DSP digital signal processor, audio amplifier circuit, temperature sensing circuit and smog alarm testing circuit.

2. 800MHz digital radio baby monitor according to claim 1 is characterized in that: described emission LCD liquid crystal display displaying contents comprises radiationless pointing character, pairing character.

3. 800MHz digital radio baby monitor according to claim 1 is characterized in that: described reception LCD liquid crystal display displaying contents comprises radiationless pointing character, smog alarm pointing character, baby head picture collection of letters pointing character, pairing character.

4. 800MHz digital radio baby monitor according to claim 3 is characterized in that: described baby head picture collection of letters pointing character comprises sleep pattern, the pattern of crying and screaming, painful pattern.

5. 800MHz digital radio baby monitor according to claim 1, it is characterized in that: described radio frequency amplifying circuit comprises rf chip, transmit-receive switch chip, low-pass filter.

6. 800MHz digital radio baby monitor according to claim 5, it is characterized in that: described rf chip operating voltage is 1.9～3.6V, and rf chip inside comprises power amplifier, voltage controlled oscillator, High Amplifier Circuit, mixting circuit, mould/number conversion circuit and DLC (digital logic circuit).

7. 800MHz digital radio baby monitor according to claim 1, it is characterized in that: described DSP digital signal processor comprises audio coder ﹠ decoder (codec), note amplifier.

8. 800MHz digital radio baby monitor according to claim 7, it is characterized in that: described audio coder ﹠ decoder (codec) working current 1.9mA, sample frequency is 16～128kbps, and audio coder ﹠ decoder (codec) inside comprises microphone preamplifier, programmable filter, audio amplitude adjustment register and voice mould/number conversion and D/A.

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