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LED Beacon With Timer, Refer to IRF3205

2014-12-22 02:45  
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The proposed device is intended to refer to any temporary objects, hazardous locations, drawing attention to favor size or abnormally located subjects. It can also be used in various games. A distinctive feature of the lighthouse is that it is equipped with a timer, so after a certain period of time after power is automatically turned off. Maximum shutter speed is about 90 minutes. In standby mode, the device consumes less than 0.1 mA, which in most cases is less self-discharge current of the battery. The light source used high-brightness LED, so the TT it is economical.

Diagram of the device shown in Fig. 1. To "flashing" LED and resistor R1 HL1 assembled pulse generator, logic elements DD1.2, DD1.4 function as inverters, chip DD2 - chetyrnadtsatirazryadny binary counter, the transistor VT1 provides switching LED HL2.

After the supply voltage starts to charge the capacitor C1 through resistor R2. At the moment, this resistor and the input R counter DD2 present high level, which will install all of its output is logic low. At the output of the DD1.2 is high, and the LED will go HL1 voltage. Current drawn by the "blinking" LED periodically increases sharply, and the resistor R1 occurs voltage pulse that arrives at the elements DD1.1 and DD1.3. The stability of the oscillator is low, but these devices do not need it and it lives simplicity. Since the current through the LED HL1 does not exceed the share of milliamps, it flashes almost invisible. The output element DD1.1 inverted pulses on input from counter DD2, where is their expense. Simultaneously with the momentum in the resistor R1 and the impulse on the output element DD1.4, transistor VT1 HL2 opens and LED flashes.

With each pulse generator output status meter changes, and when the output 2e (pin 12 DD2) appears high, the output of the high level DD1.2 replaced by low and the generator stops. HL2 LED flash will not, and in that - stand - state device can be arbitrarily long, practically draining the battery, even if you do not turn off the power. To run the lighthouse turn off and turn back on. In this case, a closed contact switch SA1 capacitor C2 quickly exhausted, and it is necessary to discharge the capacitor C1, so that when you switch on the beacon installed on the output by DD2 low.

Duration of the beacon depends on which of the output of the counter inputs connected DD2 gate DD1.2 and the frequency of "blinking" LED HL1. For these items for the duration of the scheme is about 2 min 20 s. In a small range that can be altered selection of resistor R1 (from 3 to 100 kW), and the big ones - the choice of the output circuits DD2, which is connected to inputs of the element DD1.2. For example, to increase the duration of the lighthouse twice DD1.2 input element should be connected to the output 29 (pin 14) | counter DD2. The maximum duration of the beacon - about 90 minutes - I will when I connect to the output element DD1.2 213 (pin 3) of the counter DD2.

The device used fixed resistors MLT, oxide capacitors - imported, the transistor can be replaced by a transistor KP504A KP501 with any letter index or chip KR1014KT1A. Power switch - any compact, for example, MT-1, MTS-102, SMTS-102, LED ARL-3014URD-B is replaced by the ARL-5013URC-B or MSB557DA. LED 10G4DHCBB20 - on the ARL-5613URW - red, ARL-5213PGS - green, ARL-5013UWC, ARL-5613UWW - white glow. To power the battery can be used 3R12P or three galvanic cells connected in series, size AA, AAA. If the LED is used HL2 red or green glow, the efficiency remains a beacon for supply voltage 3 ... 6 V.

Most of the details are available on the printed circuit board unilaterally foltirovannogo fiberglass thickness of 1 ... 1.5 mm, the drawing of which is shown in Fig. 2. Boards are installed in a rectangular plastic case, for example, soap dish about the size 105x65x35 mm. The appearance of a possible embodiment of the device shown in Fig. 3. Power switch SA1 attach to the front panel and the LED HL2 - on the top wall.

Before installing the electronic components mounted on the printed circuit board to mount the jumper wires. To install the chipset and MOSFET is desirable to apply the panel. In addition, for the transistor trehgnezdovuyu panel you can do yourself, using one vosmivyvodnuyu panel circuits. First, it is cut so as to obtain two panels on four pins, and then one of them is removed, it can be done with the assembly pliers.

Frequency and amplitude of the pulse generator in a small range can be changed by selecting the resistor R1. To change the duration of the beacon is necessary to adjust the topology of the circuit board. If it's already made, then cut the printed conductor connecting pin 12 DD2 chip with the conclusions of 8 and 9 element DD1.2, and install a jumper wire between terminals 8, 9 and the selected element DD1.2 output counter DD2. Current through the LED HL2 set selection resistor R3, for the drain and source of the transistor VT1 temporarily connect a jumper. Increasing the LED current HL2 to a maximum (80 mA) is pointless, since more than 50 mA current brightness of its luminescence subjectively increases slightly. That when the HL2 LED beacon within the time is lit constantly, the conclusion one element DD1.3 disconnect from the cathode LED HL1 and connected to terminal 2 of the same item. Using a more powerful light source, such as incandescent lamps, you must apply FETsIRF3205, IRL2505Land high capacity batteries.