The following project can either stand alone as a plug-in peripheral, or be integrated as part of the TRS-80 keyboard unit. In either case, the specifications are: The hardware involved in this project, including power supply and miscellaneous hardware, will be under $100 (probably closer to $70 by the time you read this), yet will compete easily with any
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high-resolution add-on for the TRS-80. On the negative side, this project will invoive a great deal of wire wrapping or soldering, and will eat up one chunk of 16K memory address space when it is used. It will not actually compete with or replace the top memory block in the expansion box (there is no electronic conflict) but will be addressed from COOO to FFFF. Alternatively, it may be addressed from 8000 to BFFF. In either case, you do not need the expansion box to run this memory. pixels by 3 pixels (a pixel is a picture element`) for the familiar coarse graphics mode accessed with SET and RESET. If you turn the contrast fully down and reduce the brightness of the screen, the individual dots which make up the graphic and alphanumeric characters can be seen with a sharp eye; a magnifying glass will make the dots very clear. In order to produce a complete screen line of letters, the locations in video memory are handed to a circuit which actually accesses them twelve times - once for each pass the electron beam makes horizontally. At each pass, a row of dots corresponding to part of the whole line of letters is shifted out to the video beam. Each dot (or undot`) then turns the hearn on or off for the tiny fraction of a second it takes to sweep across 1/384th of the screen. The point is clear: an electronic event takes place for every dot on every line of the screen. This means that it is possible to create an individual,...
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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