HC-SR501 is based on infrared technology, automatic control module; imported from Germany LHI778 probe design; Operating temperature: -40 to 85 ° C; non-permanent; Storage temperature: -40 to 85 ° C, non-permanent, high sensitivity, reliability strong, ultra-low voltage operation mode, widely used in various auto-sensing electrical equipment, especially battery-powered automatic control products. Double potentiometer with mode jumper.
• Security Products • body sensors toys
• Human sensor lamps • Industrial automation and control
• Sensing range:
1. Automatic Induction: When people enter into its high sensing range, sensing range of people leaving the automatic delay off high output low.
2. photosensitive control (optional): Module reserved for a position, you can set the photosensitive control, day or light intensity without induction when photosensitive control is an optional feature, the photoresistor is not installed at the factory, if necessary, be purchased separately photoresistor. install their own.
3. Two trigger modes: L can not be repeated, H can be repeated jumper selection, the default is H..
A. unrepeatable trigger: the sensor output high, the delay time has elapsed, the output will automatically from high to low.
B. repeatable trigger: the sensor output high after; if there is human activity in its sensing range;; in the delay period the output will remain high; until the people left after the delay will be high level to a low level (will be automatically extended after sensing module detects the human body every activity a delay period, and to the last activity time as the starting point of the delay time).
4. With induction blocking time (default: 0.2 seconds): sensor module after each sensor output (high to low), can be followed by a blockade set time, during this time period the sensor does not receiving any induction signal This feature can be achieved (sensor output time and blocking time) two interval work can be applied to interval detection products; at the same time this feature can inhibit the process of load switching for a variety of interference generated.
5. Wide operating voltage range: DC5V to 20V operating voltage Default
6. Micropower: quiescent current of 65 microamps, especially for battery-powered appliances.
7. Output high level signal: easy docking with the various types of circuit realization.
After an induction module is powered initialization time a minute or so, at this time interval output module 0-3 times a minute after entering standby.
2. should avoid lens lighting and other sources of interference close to direct the module surface, in order to avoid the introduction of interference signal generator malfunction; try to avoid using the environment
Free flow of wind, the wind sensor will also cause interference.
3. The sensor module uses dual probe; probe rectangular window; double yuan (A Yuan Yuan B) located at both ends of the longitudinal direction, when the body from left to right
Or from right to left through time; IR arrival dual time; there is a difference distance; the larger the difference; the more sensitive the sensor; when the body from the front to the probe
Head or top to bottom or from bottom to top direction through time; Dual IR undetectable changes in the distance; no difference; therefore induction insensitive or does not work; it should be installed sensor probe dual direction and most human activities as much as possible in parallel direction; to ensure the human body has been through
Dual probe induced. In order to increase the angular range sensor, the module using a circular lens, but also makes the probes on all four sides induction, but left and right sides remain
However, in both directions up and down a large sensing range, sensitivity stronger than, the installation must still try to press the above requirements.
Pyroelectric sensor basics and use common problems
Pyroelectric infrared sensor to detect a person or animal and outputs an electrical signal emitted by infrared sensors. As early as 1938, it was proposed the use of pyroelectric effect to detect infrared radiation, but not taken seriously until the sixties With the rapid development of laser and infrared technology, it has promoted the research and application of pyroelectric crystals on the pyroelectric effect. pyroelectric crystal has been widely used infrared spectroscopy, infrared remote sensing and thermal radiation detectors, It can be an ideal detector as an infrared laser which targets are being widely applied to various automation control devices. In addition to automatically switch in the corridor as we know, has been applied on the burglar alarm, but in more areas application prospects, such as: no one in the room when the air conditioner will automatically shut down, drinking fountains TV can judge no one watching or sleep after the viewer has the automatic shutdown mechanism opens on the monitor or use a combination of automatic doorbell camera or. digital camera automatically records the animal or human activity and so on. You can according to their own whim, in combination with other circuits develop more excellent new products. or automatic control devices.
Pyroelectric sensor Basics
Similar to the pyroelectric effect of the piezoelectric effect, is due to temperature changes caused by the phenomenon of crystal surface charge. Pyroelectric sensor is sensitive to temperature sensors. It is made of ceramic oxides or piezoelectric crystal components, the component two surfaces made of electrodes is within the range of sensors to monitor temperature change ΔT, the pyroelectric effect will be on the two electrodes produce a charge ΔQ, that is, between the two electrodes produce a weak voltage ΔV. Since its high output impedance, there is a field effect transistor in the sensor impedance transformation. charge ΔQ generated by the pyroelectric effect will be bound to disappear in the air ions, namely, when the ambient temperature is stable and unchanging, ΔT = 0, No output when the sensor body into the detection zone, because the body temperature and ambient temperature difference, resulting in ΔT, there ΔT output;. If the body does not move into the detection zone, the temperature does not change, there is no output of the sensor so that. types of sensors to detect human or animal activity sensor by the experiment proved that the sensor without the optical lens (also known as Fresnel lens), which detects the distance is less than 2m, and coupled with an optical lens, its detection distance may be greater than 7m.
Use should note the following:
First, the DC voltage must comply with values too high and too low will affect the module performance of our requirements and the requirements of a well-regulated power supply must be filtered, such as computer USB power supply, cell phone charger power supply, older 9V laminated battery Modules are unable to meet the job requirements, it is recommended customers use the power transformer and through three-terminal regulator chip voltage regulator and then through the power supply after 220UF and 0.1UF capacitor filter.
II; commissioning body as far away from the sensitive region; sometimes in front of the body, although not in the module; however, when the body is too close module from the module can also be sensitive to the cause has been output; and when debugging the human body do not touch the circuit section can also affect module ; more scientific approach is the output end of an LED or a multimeter; the module is covered with a newspaper; people leave the room; and so two minutes later to see if the module or has been output?
Third, when the module is not connected load to work, after work load connected to disorder, one reason is because the power supply capacity is relatively small load power, voltage fluctuation caused by the load at work cause the module to malfunction, and the other reason is that the load It will produce electrical work interference, such as relays or solenoids and other inductive load will produce back electromotive force, when there will be 315M launch board work electromagnetic radiation will affect the module solution is as follows:.. A, power supply section plus inductor filter B, In load and module methods using different voltages, such as: load using 24V operating voltage, the module uses 12V operating voltage, during a three-terminal regulator isolation C:. use a larger capacity power supply.
Fourth, the human body sensing module can only work in indoor and working environment should be protected from sunlight, direct exposure to intense light, if the work environment has a strong RF interference, shielding measures can be used. In case there is a strong air turbulence, doors and windows closed or blocked convection. Induction Try to avoid facing the district heating appliances and objects and easily windblown debris and clothing.
Fifth, the human body sensing module is recommended to install in a sealed box, or it may have been the output signal.
Sixth, if the requirements of the human body sensing module detection angle less than 90 degrees, the lens can be obscured by opaque tape or cutting narrow lens to achieve.
Seven human body sensing module with dual element probes, the body's limbs and head movement direction and sensor sensitivity are closely linked, and the characteristics of the infrared module determines the sensing distance can not be precisely controlled.
Eight, module probe (PIR) can assembly and welding on the other side of the board may also be shielded probe with dual-core line extension, the length should be less than 20 cm as well.