Showing posts with label sound. Show all posts
Showing posts with label sound. Show all posts
Tuesday, April 30, 2013
Sound Activated Switch II
With this sound activated switch, control by sound may be very useful, not just on a robot but also for a bit of home automation, for example a sound-activated light responding to a knock on the door or a hand clap. The light will be automatically switched off after a few seconds. An alternative use is burglar protection — if someone wants to open the door or break something the light will come on, suggesting that someone’s at home. The circuit can work from any 5–12 VDC regulated power supply provided a relay with the suitable coil voltage is used.
Sound activated switch circuit diagram
Sound activated switch circuit diagram
When you first connect the supply voltage to the sound activated switch circuit, the relay will be energised because of the effect of capacitor C2. Allow a few seconds for the relay to be switched off. You can increase or decrease the ‘on’ period by changing the value of C2. A higher value results in a longer ‘on’ period, and vice versa. Do not use a value greater than 47μF.
Biasing resistor R1 determines to a large extent the microphone sensitivity. An electret microphone usually has one internal FET inside which requires a bias voltage to operate. The optimum bias level for response to sound has to be found by trial and error. All relevant electrical safety precautions should be observed when connecting mains powered loads to the relay contacts.
Biasing resistor R1 determines to a large extent the microphone sensitivity. An electret microphone usually has one internal FET inside which requires a bias voltage to operate. The optimum bias level for response to sound has to be found by trial and error. All relevant electrical safety precautions should be observed when connecting mains powered loads to the relay contacts.
Tuesday, April 9, 2013
Logic Probe With Sound
This logic probe can be selected to operate on TTL or CMOS logic levels, depending on switch S1. A string of resistors associated with switch S1 sets the threshold levels for a window comparator comprising IC1a and IC1b. Depending on whether the level applied to the probe is high or low, the window comparator turns on LED1 (high) or LED2 (low). The 1.2M and 680k resistors set the probe signal to a midrange value when the probe is open-circuit, thereby preventing either LED from being lit.
If a pulse signal is present, the output of IC1a will toggle the clock input of flipflop IC2a. This drives LED3 which either lights for each pulse or continuously, depending on the setting of switch S2. Finally, the outputs of IC1a & IC1b are connected by diodes D5 & D6 to the base of transistor Q1 which is connected to the Reset input of flipflop IC2b. This has a piezo sounder (not buzzer) connected between its Q and Q-bar outputs so that it produces a sound which echoes the input pulse signal.
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If a pulse signal is present, the output of IC1a will toggle the clock input of flipflop IC2a. This drives LED3 which either lights for each pulse or continuously, depending on the setting of switch S2. Finally, the outputs of IC1a & IC1b are connected by diodes D5 & D6 to the base of transistor Q1 which is connected to the Reset input of flipflop IC2b. This has a piezo sounder (not buzzer) connected between its Q and Q-bar outputs so that it produces a sound which echoes the input pulse signal.
Sunday, April 7, 2013
Choosing the Right Amplifier for your Auto Sound System
Finding the best amplifier for your auto sound system can be a lot easier if you take the time ahead of time to learn what you need and what will work best with the sound system youve selected for your car, truck, or SUV. It helps to understand what an amplifier does in order to purchase the one that will best suit your needs. An amplifier takes a small sound, adds a little boost of its own, and then turns it into a big sound. The more power your amplifier has, the better quality of sound it will provide. An underpowered amplifier will have a thin, tinny sound that is rather unattractive in an auto sound system, or any other sound system for that matter.
You should also take care to remember that the power rating of an amplifier is the maximum power it is capable of expending not the amount that it will regularly use. The RMS rating of an amplifier is a good indication of its power output. One thing that is important to remember is that you should never buy an amplifier based on the maximum output or RMS rating. This number is more often than not incredibly misleading. If a driving, thumping bass beat is important to you then you should make sure that your amplifier has a bass boost button. This button will or switch will give a little bit of a boost to your bass. Its something I can pass on by many bass lovers cannot live without. Not all amplifiers have this so choose wisely and according to your preferences.
When it comes to amplifiers there are essentially four major classes (there are other classes but they are not all that common so I will not dwell on defining them) that represent the quality of sound you should expect from the system.
1) A. This class has a great output of quality sound but wastes huge amounts of energy in the process of creating that wonderful sound.
2) B. This class is slightly better than A as far as it wastes less energy and slightly worse as it produces a somewhat inferior quality of sound.
3) A/B. This resembles either A or B as far as sound and energy waste goes depending on the volume. Lower volumes will utilize the class A qualities of the amplifier while louder volumes are more in keeping with class B.
4) D. This class is primarily decent for producing a good bass sound and little else. The quality of sound and amount of energy wasted are both only moderate and neither are very impressive.
Of course this is the bare bones run through of the very basic amplifier basics. Another thing to note is that many people simply refer to amplifiers as amps rather than saying the entire word. Its slang but its so common that no one will blink if you do it. In fact you are far more likely to get funny looks for calling it an amplifier. Regardless of the small talk an amplifier isnt the end all be all of an auto sound system. It is only important if you feel it is important and many sound systems work splendidly without an extra amplifier to confuse the process and raise the price.
Whenever you decide to buy a new auto sound system for your car, truck, or SUV there is a moment of exhilaration and excitement as this is often a decision youve mulled over for quite a while rather than a spur of the moment decision. This exhilaration is promptly followed by a moment of complete and utter fear, as most of us have no clue what we really need. Hopefully, this has helped you decide whether or not you will need an amplifier and if you will, perhaps you can make a more educated and informed decision as to the type of amp you need.
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