In Amateur literature, there are many descriptions of security devices alarm systems for cars. However, most of these devices cannot to use for the protection of another popular means of transportation is a motorcycle. The author published the following article was developed specially design for "two-wheeled friend" and believes that it meets the goal.

During the collection of forest gifts of nature motorcycles, lonely standing along the roads and Prosek, become easy prey for attackers. However, stealing bicycles rare, but dismantled them, steal fuel, while the owners pick berries or mushrooms, quite often.

The proposed caretaker responds to even the weak blow to the body of the motorcycle and immediately generates an alarm signal. Moreover, the signal - musical and, of course, different from the traditional alarm signals. The owner will recognize him among other.

When developing a security device had to abandon the use the beep that is installed on the motorcycle, as it consumes from the battery too much current. Described watchman in standby mode consumes less than 1.5 mA, and in the alarm mode up to 400 mA.

The device incorporates a sensor, such as described in [1]. The basis of it is system RFP-22, mounted on the Board without modification. The sensor can be placed anywhere on the motorcycle, on the effectiveness of the watchman is no significant effect.

Schematic circuit diagram of the security device shown in Fig. 1. Upon striking the body of the motorcycle in the sensor occurs Bq 1 AC signal, which is input to the comparator collected at the OS DA1. The threshold the comparator sets a trimming resistor R2. Upper circuit position engine resistor R2 corresponds to the minimum sensitivity of the device.

E-watchman for motorcycle

If the amplitude of the negative half-wave of the sensor signal is less than the voltage on the resistor R2, the transistor VT1 operating in the switching mode, remains closed and the output voltage at its collector is low. As only the amplitude of the half waves will exceed the voltage at the resistor R2, the output voltage of the transistor VT1 will be a sequence rectangular pulses. Diode VD1 increases the dead zone transistor VT1.

Operational amplifier DA1 operates at maximum gain. Current consumed Oh, depends on the current flowing through the pin 8; resistor R5 normalizes this current. If it is in the range of 1.5...15 mA, then the current consumed Oh DA1, is $ 36...170 μa. The resistance of the resistor R5 (in megohms) calculated by the formula [2]: R5 = (u pit-0.7 V)/I8 where u pit - voltage supply Oh, In; I8 - the current through the pin 8, MCA.

Rectangular pulses from the collector of transistor VT1 is fed to the input S of the flip-flop DD1.1, which leads to the switch in one state. The direct output the trigger level is set to high. Subsequent pulses coming from collector VT1 to the input S of the flip-flop, not change its state.

Voltage high-level output of the trigger DD1.1 through the resistor R9 begins relatively slowly charging the capacitor C1. The battery charges to about 40 C. As the voltage on the capacitor C1, and hence the input R of the flip-flop will reach the switching threshold of the trigger in the zero state, the trigger switch on the the direct output will be set low level, if at this point closed transistor VT1 and the input S of the flip-flop ceased to flow pulses.

Oh DA1 and trigger DD1.1 are powered from the parametric voltage regulator VD2R10.

The high voltage level of the direct output of the flip-flop DD1.1 opens the transistor VT2, and relay K1. Through the closed contacts K1.1, K1.2 arrives the power signal on the device is assembled on a musical synthesizer DD2.

Besides music synthesizer, it includes the audio signal amplifier DA2 and the dynamic head of BA1. Music synthesizer DD2 is powered by separate parametric stabilizer VD4R12. The synthesizer is connected so that sounds only one melody. If you want to change the melody, the scheme of his the inclusion of the need to change, as shown in [3].

Signal amplifier DA2 AF is powered directly from the battery the motorcycle. Resistor R13 prevents the excitation of the amplifier. Chain OS formed elements C5, R14, R15. Resistor R15 is necessary when establishing a be chosen so as to achieve maximum gain [4]. Dynamic head BA1 connected to the amplifier DA2 through a separation the capacitor C6. Free terminals 3-6, 9, 11 DD1 chip are connected to a common wire.

All parts of the device other than the switch SA1 and dynamic heads BA1, mounted on the circuit Board of foiled fiberglass with a thickness of 1 mm the Drawing Board is presented in Fig. 2.

The switch SA1 to be installed in a location known only to the owner of the car. Dynamic head must be protected from deliberate damage. Diffuser it is preferably impregnated with a waterproof varnish.

Cost also need to be protected from splash and dust proof durable box, and the mounting cover epoxy varnish.

The vibration sensor can be made on the basis of the sound projector CP-1 and others. Chip CUM can be replaced by CAD, and the trigger KTM - on KTM. The synthesizer UMS any of this group; they differ only recorded in their melodies. Quartz resonator ZQ1 mind, any time on a specified frequency.

Instead amplifier CAN suitable TDA2003. Transistors VT1, VT2 can be any of these series. Diodes VD1, VD3 - any of a series KD521, KD522. Zener CSA to replace XI and XA - XA or stabistor CSA, but with a change in polarity. Relay K1 - RES, passport RS4.569.435-02. The dynamic head 3ГLW-1 can be replaced by GD, GD, 6ГLW-2. A push-button switch SA1 - P2K.

Accurately collected from the healthy parts of the device usually starts to work immediately. Resistor R2 regulate its sensitivity after being placed on the motorcycle. Too high sensitivity to install is not recommended otherwise the alarm will respond to the vibration of the soil from a passing transport, and even light crackling cooling after stopping the motorcycle.

The sensitivity also depends on the location of the vibration sensor when attaching it to the frame or other metal structural members the sensitivity can be excessive.

To exclude acoustic coupling between the dynamic head BA1 and sensor vibration BQ 1 in which the alarm will be repeated continuously without external influences on the sensor, it is necessary to experimentally find a place the installation head, the rigidity of the hinge and the sensitivity of the sensor.

Power source guard serves as a motorcycle battery. If the vehicle is operated without batteries, you need to install it.

In standby mode the device include a contact closure SA1. If you try then manipulate the control levers, remove the motorcycle with a step or to budge, the guard will immediately served an alarm signal. It will be sound about 40 s, during this time, the melody will manage to sound completely. Then, when the condition that external influence has ceased, the alarm will go in suspend mode.

As you know, on a motorcycle are not many places suitable for install dynamic heads, so count on the fact that it will be possible to ensure that no spurious acousto-mechanical connection between it and the sensor (if its sensitivity is acceptable), there is no reason.

However, this parasitic coupling can be eliminated by simple revision the watchman. First, you need one of the two contact groups relay K1 (see diagram) "transfer" in the gap positive wire at point b, and use a pair closed relay contacts (terminals 11, 12 or 21, 22). To nourish the trigger DD1.1 should the refrigeration output of the Zener diode VD2. Secondly, the capacitor C2, increasing its capacity is 2...5 times, should be soldered to the left of the point In the scheme, and still the place to install ceramic capacitance of 0.1...0,22 µf.

After this alteration in standby mode, the OS and the transistor VT1 watchman will be to work as stated in the article, but once triggered, the relay K1 and sounds alarming, Oh and the transistor VT1 will be de-energized. After some the time relay will return to its original state, but the sensitivity of the guard will be restored only after 0.1...0.3 s after charged oxide the capacitor C2.


  • Vinogradov, Y. vibration Sensor for security devices. Radio, 1994, No. 12, p. 38.
  • Bulychev, A. L., and others. Analog integrated circuits. - Minsk, Belarus, 1993.
  • Vasiliev A. On chips series UMS. Radio, 1995, №12, p. 40.
  • Novachenko I. V. et Circuits for household radio equipment. The Handbook. - M.: GOBLET-a, 1995.
  • Supplement

    As to eliminate the crackling of a motorcycle is extremely difficult, we have to deal with false positives guard. The circuit of the alarm, free of this drawback is shown in the figure. The vibration sensor BQ 1 left the same, but some changes made in the circuit it is connected to the comparator at the shelter DA1.

    Counter DD1.1 counts the pulses coming from the comparator. Generator elements DD2.1, DD2.2 and counter DD1.2 form a node generates impulses counter reset DD1.1. On the elements of DD2.3, DD2.4 assembled sound generator the frequency of its output pulses increases the current in the transistor VT1, loaded dynamic head HA1.

    The device includes in standby secretly installed a toggle switch SA1. In this the time pulse from circuit C2R5 resets the counters DD1.1 and DD1.2 input Generator R. DD2.1, DD2.2 begins to produce rectangular pulses with a frequency of about 2 Hz, which takes into account the counter DD1.2.

    After about 4 with the output 8 of this counter appears briefly high level, which again will reset the counters. Thereafter every 4 input R counters will be reset pulses.

    Fluctuations in the voltage from the sensor BQ 1, the resulting vibration frame motorcycle, proceed to the non-inverting input of op-amp DA1 is enabled by the comparator. To the inverting input of voltage from the divider is adjusted resistor R3, which sets the switching threshold of the comparator, or otherwise, and the sensitivity.

    The rectangular pulses from the output of the comparator, the counter counts the DD1.1 the entrance CN. If for 4 with a time counter to count eight pulses, output 8 will display a high level, which will allow the sound generator on the elements of DD2.3, DD2.4. The duration of the alarm depends on how soon the meter registers eight pulses, or, in other words, how intense vibration of the vehicle body.

    This provides an insensitivity of the guard to single clicks. When random external influences on the bike he will be giving a short non-periodic signals, and only when, attempted theft or disassembly of parts of the signal the alarm will sound almost continuously.

    Diode VD2 protects your device from accidental polarity reversal of the voltage power. The accumulation time of the pulses of the external effects and duration an alarm signal can be increased if the capacitor C1 is replaced by another, greater capacity. Thus, when the container 1 µf duration will almost double.

    For assured watchman must be carefully set the desired the sensitivity of the comparator trimming resistor R3.Before first use the engine of this resistor is set to the middle position. Include guard and, monitoring with an oscilloscope the signal at the output of the comparator and drumming the body of the motorcycle, slowly move the slider to the resistor R3 down the scheme, seeking the trigger guard.

    Recommendations for placement of the sensor device design, installation dynamic head based on the capabilities of acoustic coupling between the head and the sensor set out in that article. Because the device does not require high the temperature stability of RC-circuits, it is possible to use virtually any details.

    Chip CUT can be replaced by COD, COD. Instead CLE suitable CLA, in this case, you can eliminate the diode VD1, one of the inputs of the element DD2.3 connect to the input 8 of the counter DD1.1 and the other end to the junction point of elements R8 and C3.

    A sound projector CP-22 to replace SN-5. Instead of the transistor will fit any CTB from CT. Diodes CDB you can use any silicon (for example, from series KD521).

    Watchman consumes in standby mode, the current of about 6 mA, and the alarm mode is about 300 mA. It can be powered from the battery of the motorcycle, from any and another source providing a current of at least 300 mA for at least one hour.

    To ensure optimal sensitivity and ensure its the stability of the resistance of the trimming resistor R3 is better to choose equal to 10 com and in the upper and lower chain according to the scheme of its findings include sequentially permanent resistor 43 ohms.

    Author: M. Churukian

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