Homemade earthquake alarm, Earthquake alarm
Keywords: homemade earthquake alarm
Homemade earthquake alarm
The seismic alarm introduced here is to use the time difference of seismic longitudinal wave and horizontal wave, as long as it is installed in the room, you can sleep peacefully. An earthquake activity, the first longitudinal wave will trigger the circuit to send alarm and lighting light. At this time, people can strive to quickly escape within ten seconds before the arrival of horizontal waves, and can minimize casualties to minimize casualties.
I. Working principle
The earthquake alarm circuit is shown in Figure 1. The hollow coil L is constituting the seismic longitudinal wave detector, the crystal transistor Vt1, Vt2, and the unidirectional thyristor Vs Vs or the like, and the HA is the alarm dedicated electric horn, and HL is the lighting small bulb.
When there is an earthquake activity, the small magnet first feels the impact force of the longitudinal wave. When the impact force is large enough, the small magnet can be made up and down in the hollow coil, and an alternating induction voltage is generated at both ends of the coil L. The alternating voltage is enlarged, C2 coupling, and the VD is rectified, and the negative pulse signal is generated, and the unidirectional thyristor Vs obtains the trigger signal. The alarm dedicated electric horn HA is powered to send a hars-loud siren Sound, wake the owner from sleep; at the same time, the lighting small light bulb HL makes shines, and the road to the escape.
The circuit is in monitoring the alarm state, the triode VT2, and the unidirectional thyristor Vs are at an off state, and the circuit static total current is only about 1 mA. Once the sound, the light alarm will continue until the power switch SA is turned off.
Second, the component selection
Vs uses common MCR100-1 or BT169D, CR1AM-6, 2N6565, etc. Small-plastic single-way thyristor (also called one-way thyristor), and the shape is equipped with ordinary plastic packaging small power triode 9014, Figure 2 is the shape and pin Note not to the wrong pin when you are arranged.
VT1 uses 9014 (collector maximum allowed current ICM = 0.1a, the collector maximum allowable power consumption PCM = 310mW) or 3DG8 silicon NPN small power triode, requires current amplification coefficient β>150; VT2 9015 (IEM = 0.2a, PCM = 200mW) or 3CG21 silicon PNP small power triode, requiring current amplification coefficient β>80. VD uses 1N4148 silicon switch diode.
The coil L wraps 1000 to 1500 hinders in a hard plastic tube having an inner diameter of 15 mm, a length of 30 mm, and a hard plastic tube having an inner diameter of about 15 mm and a length of 30 mm. The small magnet volume used in conjunction with L is too large, a permanent magnet of about 10 mmX10 mmXl5mm can be used to ensure that it can vibrate up and down in the coil tube.
HA uses TWH11 (DC operating voltage 12V, working current 0.2a, degree 120dB) super loud alarm speaker, or other DC operating voltage 12V, operating current. 1881.0.3a analog wander flute, monocular electric horn or electric horn. HL uses DQ12-5 (12V, 5W) spherical light bulbs, or other parameter lighting light bulbs can be replaced.
R1 ~ R3 all use RTX-1 / 8W carbon film resistors. C1 to C3 are used with CD11-16V type electrolytic capacitors. SA is single-throw switch with a small single knife. G It is preferred to use an internal resistance of a solid 12V small battery, or it can be replaced in series with 8 large dry batteries.
Third, production and use
Figure 3 shows the printed plate wiring diagram of the seismic "alarm", and the actual size of the printed board is about 40 mmmmm.
The welded circuit board is loaded with the coil L, and the battery G is loaded into an insulating staple cartridge. The cartridge opening fixed small bulb HL, the electric horn HA, and the power switch SA; the upper surface of the box extension the hollow coil L is extended to extend into the small magnet.
When using, according to Figure 4, first select the indoor unusual person to interfere with the load wall or window frame, through the iron nail, a thin line rope and a small spring (preferably less than 10 cm length is not less than 10 cm), and will Small magnets extend in the coil tube in the circuit box. The soft and hard to the alarm sensitivity is large, in order to enable the circuit to obtain sufficient exploration sensitivity, there are several different specifications, and the comparison test is turned on one by one. Elect the spring that can make the small magnets up and down by pushing a small magnet with hand. If there is no suitable small spring in hand, replacing the rubber band with elastic force, the effect is good. Be
In addition, the small magnet must be in the intermediate position of the hollow coil in the circuit box, and the flexible movement can be flexible to enable the coil to achieve a higher monitoring sensitivity, which can change the length of the fixed circuit cartridge to adjust the length of the thin wire rope. . Zhang Xiaodong
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