building vu meter

Posted on Feb 7, 2014

Need to amplify the output of the iPod`s headphone jack would not be enough to provide the chip with a large enough signal to respond to, but this was because I had been researching three different chips. The LM3914 is a linearly calibrated device, so its output will change one-per-volt of the input. This could be a problem for low-voltage inputs like my iPod headphone jack - they would need to be amplified.

building vu meter
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The LM3915 is a logarithmically calibrated chip, where the input exponentially alters the LED output. This is much more useful for me, as the top LEDs of the meters will respond well to the loud peaks of my music. The LM3916 is a more technical chip, and less useful for what I want, as it is calibrated by the decibels of the input. I am not so sure how this is calculated or interpreted by the chip, but here is another crude diagram: I have an A* GCSE qualification in Electronics, and I have *just* taken my exams for AS-level Electronics. I have test equipment at home and soldering irons etc. I would like to buy a pre-made kit but if that`s not possible i am able to create my own and test on Circuit Wizard. Depending on the source of the signal, you need to attenuate the signal down to a useable level, then run it through a series of Band Pass Filters, then those Band Pass circuits into a series of power circuits sufficient to drive as many LEDs are you need to get the job done. I was equally confused which is why I posted both frequency oriented links and sound level oriented links. My initial reactions was Frequency oriented, as he says low bass, mid bass, and high bass. But, I wonder if he doesn`t simply mean low level, mid level, and high level signals, implying that this is a VU meter purely to display signal level. So the original poster needs to clear that up. Is he trying to block out the sound spectrum by frequency...

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