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working principle
The circuit of the anti-theft alarm telephone system is shown in the figure, and the system is mainly composed of three parts: a robbery circuit, an automatic dialing telephone circuit and a voice generating circuit. IC1 is a micro-chip vibration sensor module, IC2 is a pyroelectric infrared sensor module, they and R1 a R3, Cl a C3 and VD1, VD2, VTl, etc. constitute a probe theft circuit. IC3 and external components connected into a typical monostable trigger, it and VT2, relay K and other constitute a delayed call circuit. IC4 is a voice recording board that can record the required alarm language with a limited time of 6 seconds.
Both ICI and IC2 modules have a simple time identification circuit (composed of R2, C2, R3, and C3 delay circuits) at the output of the IC2 module, which has the function of identifying the owner and the thief. When the owner opens and closes the door, the IC1 is not vibrated for the time los. Although IC1's 2 pin outputs a high signal of los, the charging voltage at both ends of C2 does not reach 1.3V, VD1 cannot be turned on, and the subsequent circuit is not jobs. During this time, the owner can safely lock the door away from home or open the door and lock it into the room without triggering the alarm circuit. Similarly, when the master's walking time within IC2's effective detection range is less than 5 seconds, although IC2's pin 1 also outputs a high signal, the charge voltage at both ends of C3 is less than 1.3V, so VD2 cannot be turned on, and the subsequent circuit still does not jobs. Within 5 seconds, the owner can comfortably close the concealed power switch SA to leave the room or go back into the room and switch off the switch SA. Another advantage of setting the delay circuit at the output of IC1 and IC2 is that it can avoid false alarms caused by external interference and occasionally triggering ICl or IC2.
When the thieves yoke to open the door, as long as the interval time exceeds los two consecutive vibration signals (or continuous vibration time exceeds los) acting on IC1, the charging voltage across C2) 1.3V, VDl, VTl successive conduction, IC3 2 The foot gets a negative pulse trigger signal. Makes the monostable circuit formed by IC3 into a transient state. Its 3-pin output is up to 60s high, the R7 current limit, V-generation current amplification, drive relay K pull. Its movable contact K1 - K3 is closed, K1 is turned on to enable the telephone to complete the off-hook operation; K2 is connected with the "one-touch dialing" emergency call button on the telephone, so that the telephone automatically dials the previously stored number to alarm K3 is connected to trigger the pre-recorded 6s alarm voice signal so that the other party's telephone can hear the alarm speech over and over again, or it can be sent to the Chinese BP machine that the owner carries with him. If a thief breaks through a window room or uses a more clever tactic to break into a door in los, although IC1 fails to get a trigger alarm, there is still a second “gateway†set by IC2. As long as the thief walks more than 5s within the effective detection range of IC2, the charging voltage at both ends of C3) is 1.3V, which also makes VT1 turn on and completes the above-mentioned automatic dialing call alarm task. If IC3 fails to open the monitoring phone (or call the personal BP machine) within 60s after the trigger, the burglar activity does not stop. After 60s, it can be automatically redialed and sent again until the owner or security guard arrives at the scene. After the switch SA is opened, the circuit can be released.
In the circuit, RP is an external gain adjustment potentiometer of IC2. R6, C6 constitute the initial power negative pulse generating circuit, which is mainly used to eliminate IC3 high-level output caused by the momentary impact of the switch SA, which can effectively avoid false alarm when the switch is turned on. VD1 and VD2 are isolation diodes, which make the output states of IC1 and IC2 not interfere with each other.
Component selection
IC1 should use the XDZ-01 micro-laminar vibration module produced by the Institute of Electronics, Anyang City, Henan Province. IC2 uses the HN911L micro power pyroelectric infrared sensor module, which is required to be equipped with a Q-IA (58. 8mmx45mm) Fresnel lens type of finished plastic shell, so that its horizontal detection angle up to 850, the most remote detection Up to clever m. IC3 is best to use 567555 or CB7555 type CMOS time-base integrated circuit, because its quiescent current is very small, only 100tcAo such as the use of ordinary bipolar time-based integrated circuits, such as NE555, quiescent current is usually up to several mA (mA), Not conducive to reduce the overall static power consumption. IC4 selected domestic QX-5506 static 6s voice recording module, which uses black paste soft package, the 6s chip UM5506 packaged in a small printed circuit board.
The module is powered by four AG10 zinc oxide miniature button batteries. As long as you keep on electricity, you can guarantee that the recording will not be lost for a long time. When the module board is used in this device, the speaker should be removed, and the 4 leads are connected to the circuit through pins 2 and 6 of the chip (that is, both ends of the audio button) and pins 11 and 12 (the original speaker terminals).
VT1, VT2 can use 9014 and other silicon NPN transistor, requiring the current amplification factor sum) 100. VD1, VD2 available 1N4148 silicon switching diodes.
RP uses WS-XX self-locking organic solid potentiometer. R1 and R8 adopt RTX-1/8W carbon film resistors.
C1 to C4 and C6 use CD11-16V electrolytic capacitors, and C5 and C7 use CT1 ceramic capacitors.
The SA is a 1x1 small toggle switch and can also be used with a better disguised magnetic switch. G uses 4 large batteries in series.
K uses JAG-4-3HA reed relay, if not purchased, you can make it yourself. Self-made method: Insert 3 pieces of JAG-4 normally open contact dry reed pipe into 8mmx22mm plastic pipe, and seal the two ends with epoxy resin. Then use Φ0.11mm enameled wire to wrap around 2100 turns of plastic pipe, then dip the varnish to dry it. can.
Production and debugging
The soldered circuit board, together with the battery G, is housed in an appropriately sized plastic insulated enclosure. Open the hole fixing switch SA in the appropriate part of the box panel. IC1 is led to the door through three thin wires, and is affixed to the lock on the back of the door with 502 glue (IC); IC2, together with the RP, is fitted in a special plastic shell equipped with a Fresnel lens. Note IC2's The detection window is 20-30mm from the lens (adjustable by experiment). The assembly is installed in the house where it can effectively detect human activities and is connected to the control circuit box through three thin wires. K leads out of the control circuit box through the two wires and places it in the gap position of the telephone set with IC4, R8, and C7, and picks up the telephone circuit as shown in the schematic diagram.
The burglar alarm system described in this example, regardless of whether the burglar breaks the door to open the door or breaks the window to commit the crime, it can immediately report the swindle to the designated telephone (such as the owner's office phone, "110" alarm phone, etc.) And the location of the incident, or through the use of Chinese characters to show the use of words in the home to the use of appropriate measures.