If you`re a biker or scooter rider you`ll know how easy it is to forget to cancel your flashing indicators after turning without an audible reminder. Constantly glancing at indicator lamps is hardly an option; your eyes should be on the road ahead! The simple circuit shown here provides an audible reminder. The clever bit is the way it doesn`t ann
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oy you by beeping the instant you activate the flashers but only after a preset time, in other words when your indicators are active longer than normal. Supply to the circuit is through the flasher relay. With the indicators activated a squarewave voltage reaches bridge rectifier D1-D4 via terminal T1 or T2, with the other terminal remaining grounded through the indicator lamp that`s inactive. The pulsed DC voltage is stored and smoothed in C1, with D5 preventing the electrolytic from discharging during the periods when the flasher voltage is off. This also provides an adequately clean supply voltage for the 555 timer whenever the indicators are operating. Timer IC1 is used here as an oscillator and controls a piezo sounder by means of transistor T1. The output of the 555 is active Low, meaning that initially the transistor is blocked and the sounder is silent. The timer always charges and discharges capacitor C2 to a level between a third and two-thirds of the operating voltage, producing an interval of 0. 7 x C2 x (R2 + R1 + P1) [s] The preset enables you to set this delay up to a second or so. The initial delay, before the sounder first operates, is significantly longer, however, because the electrolytic has zero charge. Only after this delay is the output active, for the pulse duration of 0. 7 x C2 x R2 (equivalent to about 0. 15 seconds), enabling the sounder to operate. This applies only when +12 V is present at the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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