"This paper mainly introduces BISS0001, and focuses on the design of anti-theft alarm circuit based on BISS0001.
BISS0001 chip
BISS0001 is a sensing signal processing integrated circuit with high performance. It is equipped with pyroelectric infrared sensor and a small number of external components to form a passive pyroelectric infrared switch, which can automatically and quickly turn on lights, buzzers, automatic doors and other devices.
It can automatically and quickly turn on all kinds of white lights, fluorescent lights, buzzers, automatic doors, electric fans, dryers and automatic hand washing pools. It is especially suitable for sensitive areas such as corridors of enterprises, hotels, shopping malls, warehouses and families, or automatic lighting, illumination and alarm systems in safe areas. Functional description CMOS digital analog hybrid ASIC. It has an independent high input impedance operational amplifier, which can be matched with a variety of sensors for signal and processing. Bidirectional amplitude discriminator can effectively suppress interference. Built in delay time timer and blocking time timer, the structure is novel, stable and reliable, and the mediation range is wide. Built in reference voltage. The working voltage range is 2V ~ 6V, which is packaged with 16 pin dip and SOP. Application application application application application application products are used in a variety of sensors and delay controllers.
Design of anti-theft alarm circuit based on BISS0001
1. Passive pyroelectric infrared detector
Among the electronic anti-theft products, passive pyroelectric infrared detector is widely used. Because of its stable technical performance and reliable operation, it can detect 1-5 meters of human intrusion, which is deeply welcomed by electronic professional users.
In nature, any object above the absolute temperature (i.e. 273 ℃) will produce infrared spectrum. The infrared wavelength released by objects with different temperatures is related to the temperature. Human body temperature is generally constant at 37 ℃, so the human body will emit light with a wavelength of 10? M infrared. Passive pyroelectric infrared detector works by detecting the l09m infrared emitted by human body.
Passive pyroelectric infrared detector consists of two parts. One is pyroelectric infrared sensor (PIR), which can convert infrared signals with wavelengths of 8m-12m into electrical signals, and inhibit white light in nature. Another component is the Fresnel lens. The function of Fresnel lens is to focus, that is, the pyroelectric infrared signal of the human body is focused, and then refracted or reflected on the PIR to make the PIR change. In order to be sensitive only to the radiation signal of the thermal infrared sensor, a filter of Fresnel lens is placed on its radiation surface (the sensor with the plastic cover open is in the upper left corner of the photo, with a diameter of about 10mm).
The infrared in the pyroelectric infrared detector is composed of two pyroelectric elements connected in series or in parallel, and the polarization directions of the two electrodes are just opposite, so that the effects of the background radiation of the environment in the pyroelectric infrared sensor cancel each other, so that the detector has no signal output. Once the detector detects the infrared signal of the human body and focuses through the Fresnel lens, the detector will have an output signal.
When using the passive pyroelectric infrared detector, pay attention to the following matters: the detector can only be installed indoors, and should be about 2-2.2m away from the ground, with a downward inclination angle of 15 °. Because the sensitivity of the detector to detect the human body is related to the direction of human movement, that is, it is the least sensitive to the radial movement of human beings and the most sensitive to the cross cutting direction (vertical direction) movement of human beings, the appropriate position should be selected on site to obtain the best detection sensitivity of the detector. In addition, furniture, curtains, glass and other objects shall not be separated between the installed detector and the detected human body, and shall be far away from the places sensitive to air temperature changes of refrigerators and stoves. When the ambient temperature is close to human body temperature, the detection resolution will decrease significantly.
2. Combined application example of BISS0001 chip and pyroelectric detector
The function of the circuit below is the anti-theft alarm of the unattended FM system in the warehouse. The circuit consists of three parts: (1) passive pyroelectric infrared detector PIR; (2) pyroelectric infrared switching signal I composed of infrared pyroelectric processing chip bisso01; (3) wireless voice (whistle) FM transmitting and wireless receiving alarm circuit, etc. Even if the warehouse management personnel stay away from the warehouse, they can find that thieves have invaded the warehouse of valuables.
The left end of figure (a) below is the circuit of a passive pyroelectric infrared detector (symbol PIR), which has only three terminals D, s and G, in which D is connected to power supply (+ 5V), G is grounded, and S is the signal output end of the detector. As long as the reader is familiar with the internal functions of bisoo01 in Figure 2, and then look at the pyroelectric infrared switch signal processing circuit of bisoo01 in the middle of figure (a), it is not difficult. Therefore, only the working flow of the circuit is briefly introduced here. The ⑨ pin (VC end) of bisoo01 is externally connected with the partial voltage signals of R2 and R3, which is a high potential to ensure that the trigger control end VC is always in a triggered control state. When PIR has signal output (small signal) sent to pin 14 of bisoo01, its internal amplifier OPL (see Fig. 2) amplifies the output signal of pyroelectric infrared sensor for the first stage, then couples it to pin 13 of bisoo01 by capacitor C3 and resistor R6, amplifies it for the second stage through internal amplifier Cop2, and then processes it through internal voltage comparator COP1 and Cop2 two-way amplitude discriminator, Output the effective trigger signal vs (see the label in Figure 2) to start the delay time timer inside bisoo01, and then the output signal of pin ② (control signal output end) (i.e. the output signal of bisoo01) to trigger the operation of language chip IC1. The ① pin of bisoo01 can be connected with an external working mode selection switch, which is directly connected with the power supply, and the chip is always in a repeatable trigger state, so that the alarm circuit is always in the working mode. R6 in the figure can adjust the gain of bis0001 internal amplifier. The output delay time TX can be adjusted by the size of R9 and C7 external to pin ⑥ and pin ⑤; The trigger blocking time ti can be adjusted by the external RL0 and C6 of pin ③ and pin ④.
The right circuit in figure (a) below is a wireless voice (whistle) FM transmitting circuit. Just place the circuit (a) below, namely PIR, bisooi and FM transmitting circuit, in an unattended warehouse. Then place the wireless receiving circuit in figure (b) far away from the warehouse attendant. Once PIR detects that a thief enters the warehouse, the receiving opportunity of the on duty personnel will immediately receive the alarm signal and send out a whistle. At this time, the warehouse on duty personnel can immediately take corresponding countermeasures.
IC1 (tm-801a) in FM transmitting circuit is the voice chip of whistle. Under normal conditions, the ② pin V0 of bis0001 is at low level (countless States). At this time, IC1 does not work because the trigger terminal TG is at low level. At this time, the circuit consumes little power. When someone invades the warehouse, V0 turns to high level (effective state), and its high level signal is added to IC1 trigger control terminal TG, so that IC1 is triggered to emit a whistle (such as catching a thief), and then added to pin ⑤ of IC2 (fd400) through BG1 tube to emit the whistle.
The receiver demodulation circuit placed in the warehouse keeper is shown in figure (b). After receiving the FM signal transmitted by IC2, IC3 (jd400 and fd400) in the figure is demodulated by IC3 and sent to the audio amplification circuit of the later stage, and the horn whistles.
Other functional circuits can be made by slightly modifying the circuit in the figure below. For example, instead of the transceiver circuit in the figure, R3 in figure (a) can be changed into photosensitive resistance to detect the illumination of ambient light; A relay circuit can also be added to make an automatic lighting lamp at night.
Discussion on pyroelectric infrared delay lighting controller based on BISS0001
Circuit structure and selection of main components:
The pyroelectric infrared delay lighting controller is composed of a power supply circuit, an infrared delay control circuit and a control execution circuit. The power supply circuit is composed of power transformer T, rectifier diodes VD1 ~ VD4, filter capacitors C7 and C9, bypass capacitor C8 and three terminal voltage stabilizing integrated circuit IC2. In practical application, t often selects 220V / 9V, 5VA small high-quality power transformer; In4001 silicon rectifier diode is selected for VD1 ~ VD4; IC2 adopts lm7805 three terminal voltage stabilizing integrated circuit. 220V AC forms a stable + 5V DC voltage through step-down, rectification, filtering and voltage stabilization to supply power to the whole control circuit.
The infrared delay control circuit is composed of pyroelectric infrared sensor PIR, sensitivity potentiometer RP1, pyroelectric infrared sensor signal processing integrated circuit biss00o1 (IC1), delay elements R1, C2, potentiometer RP2, photosensitive resistance Rg and other peripheral elements. In practical application, pyroelectric infrared sensors such as p2288, ph5324 and lh1956 are often selected for PIR. In order to improve the sensitivity of PIR sensor to infrared, supporting parabolic or hemispherical Fresnel lens should be installed in front of the sensor; RG adopts mg45 photoresist, and the greater the difference between bright resistance and dark resistance, the better; WSW type organic solid fine-tuning potentiometer is selected for RP1 and RP2.
The control execution circuit is composed of electronic switch VT, solid-state relay SSR and lighting lamp H. In practical application, VT often selects 9013 Silicon NPN triode, which requires β ≥100； SSR adopts jcx-2f-dc5v zero crossing compact solid state relay; H incandescent bulbs below 100W can be selected as required.
working principle:
After the circuit is powered on, when no one enters the monitoring range of the pyroelectric sensor PIR, the pyroelectric infrared sensing signal processing integrated circuit BISS0001 is in the reset state, the control signal output terminal (pin 2) VO outputs a low level, the electronic switch VT is in the cut-off state, the solid-state relay SSR is off, the lighting lamp h is not on, and the controller is in the monitoring state.
When someone enters the monitoring range of pyroelectric sensor PIR and moves, PIR can convert the infrared change emitted by human body into electrical signal output, and the output signal frequency is 0.1 ~ 10Hz.
RP2 and RG form an optical control circuit. During the day, the photosensitive resistance Rg shows low resistance under natural light irradiation. When the ninth pin level VO of BISS0001 is less than 02vdd, the trigger is prohibited, the subsequent circuits such as bisso00l do not work, and the lighting lamp h does not light up. At night or when the ambient light is dark, the RG resistance increases. When the level of the 9th pin of bissoooi is greater than 0.2vpp, bissoooi is in the monitoring state and the output% is still at the low level. If someone moves within the PIR monitoring range at this time, the PIR will output the electrical signal that changes with the movement of the human body, and send it to the input 11n + (14th pin) of the independent high input impedance operational amplifier OP1 inside the biss001 chip through RP1. After being pre amplified by OP1, it will be output by the 16th pin, coupled to the 2in - end of the 13th pin through C4, and then amplified by the second stage operational amplifier op2 inside the chip, Then it is processed by the two-way amplitude discriminator inside the chip to output an effective trigger signal to start the delay timer TX inside the chip. Finally, the state controller outputs a high-level control signal from the second pin of bisso001 to turn on the electronic switch VT, drive the solid-state relay SSR, and the H point of the lighting lamp is on.
The output high-level control signal time of pin 2 of BISS0001 is equal to the delay time of the circuit, which is determined by the time constants of delay elements R1 and C2. The time shown in the figure is 15s. Since the first pin of the chip is connected to the high level, the circuit is in the allowable repeated trigger state, that is, within the delay time (15s), as long as the person moves a little, the circuit will be triggered again, and the second pin outputs a high-level signal with a pulse width of 15s. Therefore, as long as someone is in the bathroom, the lighting lamp h will always be lit. After only people leave, after a delay of 15s, the circuit resets and the lighting lamp h goes out automatically.
epilogue
That's all about BISS0001. I hope this article can help you.
Related reading recommendation: BISS0001 application circuit diagram
Related reading recommendations: what is the purpose of BISS0001 chip? Read the full text“
Our other product:
