This new design has replaced the old one. The design shown on this page is obsolete. The new design has more features, is flash upgradable, is much easier to use, costs less, and is actually available if you`d like to buy one! It`s better than this old design is almost every way. These old pages are still available, mostly for reference. Disclaim
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er: This design data is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. Matthew Burnham reported that hy built the circuits shown in this schematic and got it to work. This diagram was drawn after I built the player, bit it looks like it`s probably correct. It`s a good idea to avoid placing the MAS3507D chip in its socket until the 3 volt power supply has been verified. The decoder chip is expensive and it probably will be damaged if 5 volts is applied. If you are very concerned about sound quality, you may want to add more power supply bypassing to the D/A converter, perhaps with ferrite beads or inductors. The CS4327 chip is supposed to be used with a low-pass filter on its outputs. I didn`t build this on my first board, but I will add it to my next design. The CS4327 data sheet has some good suggestions about what to do for a low-pass filter. The pushbuttons are very simple, and the 8051`s port pins provide the pullup resistors, so all that is necessary is to connect the three buttons. They must be normally open momentary contact types. The firmware contains some code to avoid de-bounce the signals. This last circuit is optional, but if it is not used, whatever signal would normally drive the 8051`s RXD pin must not be connected. When the firmware uses the 8051`s serial port in mode 0, both TXD and RXD...
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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