1. Name: Ankit GuptaCourse: Bsc (Pr) APS 3rd yrExamination Roll No:College Roll No: 835
2. ELECTRONIC BICYCLE LOCKIntroductionA bicycle lock is a physical security device used on a bicycle to prevent theft. It is generally used to fastenthe bicycle to a bicycle stand or other immovable object.An important difficulty in preventing the theft of a bicycle is that the wheels are easily detachable fromthe frame, and that unless both wheels and frame are secured, wheels can easily be carried away afterbeing detached. The most secure locking method therefore is to lock the wheels and frame to each otherand to an immovable object.Locking devices vary in size and security; the most secure tending to be the largest, heaviest and leastportable. Lesser equipment is used to deter attempts by less skilled and determined thieves. Thus likeother security equipment, bicycle locks must compromise between security, portability and cost. Someare made of particularly expensive materials chosen for their acceptable strength and low density.The electronic bicycle lock described here is a worthwhile alternative for bicycle owners who want tomake their bicycles‘Intelligent’ at reasonable cost. One of the benefits of building it yourself is that the circuit can be used forvirtually any make of bicycles.Working of electronic bicycle lockIn the circuit, input jacks J1 and J2 are two standard RCA sockets. A home-made security loop can beused to link these two input points. Around 50cm long, standard 14/36 flexible wire with one RCA plug perend is enough for the security loop.Fig. 1 shows the circuit of the electronic bicycle lock. It is powered by a compact 9V battery (6F22). Keylock switch S1 and smoothing capacitor C2 are used for connecting the power supply. A connected loopcannot activate IC1 and therefore the speaker does not sound. When the loop is broken, zener diode ZD1(3.1V) receives operating power supply through resistor R2 to enable tone generator UM3561 (IC1). IC1remains enabled until power to the circuit is turned off using switch S1 or the loop is re-plugged throughJ1 and J2.Assemble the circuit on a general purpose PCB and house in a small tinplate enclosure. Fit the systemkey lock switch (S1) on the front side of the enclosure as shown in Fig. 2. Place RCA sockets (J1 and J2)at appropriate positions. Now, mount the finished unit in place of your existing lock (as shown in Fig. 3) byclamps and screws.
3. Advantage It is optional for length of cable Easy to carry New innovative anti-theft device Maximum security. Keeps all your bikes / motorcycles safe and secure. Easy to use and carry. IT is easy to operate. It is the only bicycle locker specifically designed to embrace modern technology and to offer the full range of secure bicycle parking options that modern micro- electronics can offer. Functional characteristics long desired by both cyclists and facilities managers such as keyless on-demand parking, pay-parking, usage monitoring, unattended bicycle rental. It’s highly economical electronic system and allows the user to open and close the lockers electronically.
5. IC: UM3561 Features: Four sounds can be selected Typical 3v operating voltage RC oscillator with an external resistor A magnetic speaker can be driven connecting an NPN transistor Power on reset General DescriptionThe M3561 is a low-cost, low-power CMOS LSI designed for use in a larm and toy applications. Since theintegrated circuit includes oscillator and selector circuits, a compact sound module can be constructedwith only a few additional components. The M3561 contains a programmed mask ROM to simulate sirensoundAbsolute Maximum Ratings DC Supply Voltage .......................................... -0.3V to +5.0VInput Voltage Range....................................... Vss-0.3V to Vdd+0.3V OperatingAmbient Temperature.................... -10°C to +60°CStorage Temperature ....................................... -55°C to +125°C
6. Typical Application Circuits FOUR SOUND APPLICATIONS:1. Police Siren2. Fire Engine Siren3. Ambulance Siren4. Machine Gun Zener DiodeIn the previous Signal Diode tutorial, we saw that a "reverse biased" diode blocks current in the reversedirection, but will suffer from premature breakdown or damage if the reverse voltage applied across it istoo high. However, the Zener Diode or "Breakdown Diode" as they are sometimes called, are basicallythe same as the standard PN junction diode but are specially designed to have a low pre-determined Reverse Breakdown Voltage that takes advantage of this high reverse voltage. The point atwhich a zener diode breaks down or conducts is called the "Zener Voltage" (Vz).The Zener diode is like a general-purpose signal diode consisting of a silicon PN junction. When biased inthe forward direction it behaves just like a normal signal diode passing the rated current, but when areverse voltage is applied to it the reverse saturation current remains fairly constant over a wide range ofvoltages. The reverse voltage increases until the diodes breakdown voltage VB is reached at which pointa process called Avalanche Breakdown occurs in the depletion layer and the current flowing through thezener diode increases dramatically to the maximum circuit value (which is usually limited by a seriesresistor). This breakdown voltage point is called the "zener voltage" for zener diodes.The point at which current flows can be very accurately controlled (to less than 1% tolerance) in thedoping stage of the diodes construction giving the diode a specific zener breakdown voltage, (Vz) rangingfrom a few volts up to a few hundred volts. This zener breakdown voltage on the I-V curve is almost avertical straight line.Zener Diode I-V Characteristics
7. The Zener Diode is used in its "reverse bias" or reverse breakdown mode, i.e. the diodes anode connectsto the negative supply. From the I-V characteristics curve above, we can see that the zener diode has aregion in its reverse bias characteristics of almost a constant negative voltage regardless of the value ofthe current flowing through the diode and remains nearly constant even with large changes in current aslong as the zener diodes current remains between the breakdown current IZ (min) and the maximum currentrating IZ (max).This ability to control itself can be used to great effect to regulate or stabilize a voltage source againstsupply or load variations. The fact that the voltage across the diode in the breakdown region is almostconstant turns out to be an important application of the zener diode as a voltage regulator. The function ofa regulator is to provide a constant output voltage to a load connected in parallel with it in spite of theripples in the supply voltage or the variation in the load current and the zener diode will continue toregulate the voltage until the diodes current falls below the minimum IZ (min) value in the reversebreakdown region.The Zener Diode RegulatorZener Diodes can be used to produce a stabilized voltage output with low ripple under varying loadcurrent conditions. By passing a small current through the diode from a voltage source, via a suitablecurrent limiting resistor (RS), the zener diode will conduct sufficient current to maintain a voltage drop ofVout. We remember from the previous tutorials that the DC output voltage from the half or full-waverectifiers contains ripple superimposed onto the DC voltage and that as the load value changes so todoes the average output voltage. By connecting a simple zener stabilizer circuit as shown below acrossthe output of the rectifier, a more stable output voltage can be produced. Zener Diode Regulator
8. The resistor, RS is connected in series with the zener diode to limit the current flow though the diode withthe voltage source, VS being connected across the combination. The stabilized output voltage Voutis takenfrom across the zener diode.The zener diode is connected with its cathode terminal connected to thepositive rail of the DC supply so it is reverse biased and will be operating in its breakdown condition.Resistor RS is selected so to limit the maximum current flowing in the circuit.With no load connected to the circuit, the load current will be zero, ( IL = 0 ), and all the circuit currentpasses through the zener diode which in turn dissipates its maximum power. Also a small value of theseries resistor RS will result in a greater diode current when the load resistance RL is connected and largeas this will increase the power dissipation requirement of the diode so care must be taken when selectingthe appropriate value of series resistance so that the zeners maximum power rating is not exceededunder this no-load or high-impedance condition.The load is connected in parallel with the zener diode, so the voltage across RL is always the same as thezener voltage, (VR = VZ). There is a minimum zener current for which the stabilization of the voltage iseffective and the zener current must stay above this value operating under load within its breakdownregion at all times. The upper limit of current is of course dependent upon the power rating of the device.The supply voltage VS must be greater than VZ.One small problem with zener diode stabilizer circuits is that the diode can sometimes generate electricalnoise on top of the DC supply as it tries to stabilize the voltage. Normally this is not a problem for mostapplications but the addition of a large value decoupling capacitor across the zeners output may berequired to give additional smoothing.