I already have one project where arduino outputs audio signal to USB speakers via software 10-bits PWM. In first, I was not satisfied with quality of sound generated via PWM. There are just not enough speed in arduino engine to run PWM well. For example for 20. 000 Hz audio, PWM has to be at least 2 3 times higher above normal frequency range,
Click here to download the full size of the above Circuit.
or 40 60 kHz. If we multiply this value with 10-bits resolution, we would get 40 60 MHz, that is too much for small arduino to drive. In second, the idea to create multichannel audio system was boggling my mind for about a year now. This is how UNDECIMA project was born. 1 + 11, or 12 channel ! audio system running on arduino UNO board with full 10-bits resolution maximum available with internal ADC. Project gets its name because there is 1 Master channel, and 11 linearly delayed copy of the same audio stream, or Puppets channels, In its essence, this is acoustic Phase Array. As you can see on posted drawings, the heart of the project is 10-bit multiplying (parallel) digital analog converterDAC1022. Output of the IC than buffered with OPA and demultiplex`d via two 74HC4051 8-channel analog switches. Outputs of the switches loaded by sampling and hold capacitors 0. 01 uF, to filter out unwanted sampling frequency noise. DAC isconfiguredfor single supply power line. Usually, they recommend to buffer output with / high input impedance / high slew rate / rail to rail / OPA in such configuration. Which I don`t have, and it costs about half a price of DAC itself, So, this is why I implemented two variable voltage references based on NE5532 and couple of pots. Difference in voltages between tworeferences forms a span . Lower voltage creates an off-set for cheap non rail-to-rail OPA LF351, with adequate slew rate 13 V/usecond....
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.....
characters left: