This article is the result of the very positive feedback on the hardware articles that I have written so far. You LinuxFocus readers are really a great audience! Some of you wanted to know how to interface the USB bus. So here is a nice solution. We use the LCD display from the May 2002 article and make it work with the USB bus. The whole thing wi
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ll be powered from the USB bus. Therefore you do not need any extra power supply. For this article you need at least a partial installation of the Linux AVR development environment. How to set it up is described in this article: Programming the AVR Microcontroller with GCC. USB is cool because it is a modern interface and it offers the possibility to power the devices directly via the USB bus. The connectors are small and high volumes of data can be transported over a small cable. That`s the positive things about USB. The down side is that hardware design is difficult due the high frequencies and the protocol is rather complex. Just take a look a the specifications (, you want the 1. 1 specification) and you will be shocked. It`s 327 pages long and very difficult to understand. No wonder that there are soooo many faulty implementations of USB devices. A more user friendly introduction can be found at but the specification is still complex. What to do How can we interface our Microcontroller to the USB bus FTDI, a Scottish company, has the solution ( ). They offer a chip which implements a USB serial interface. One side of the FT232BM chip is rs232 and the other USB. In other words you just replace the MAX232 which you previously needed for the power conversion on the rs232 lines with this FT232BM chip and you are done. The FT232BM is a true cross platform solution. Drivers are available for multiple operating systems. 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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