I designed the ZX97 as a discrete copy of the ZX81, which was the first PC for millions of people. In the process ZX97 turned into much more than a mere copy. While it is backward compatible with the ZX81, it is in all other respects a significant improvement over the ZX81. In 1998, Rodney Knaap contacted me to offer to make a PCB of the ZX97 but
Click here to download the full size of the above Circuit.
this proved no small feat. The end result required 3 PCBs connected together with flat cables. In order to simplify the PCB for others to build I designed the ZX97Lite, a trimmed version of the ZX97 omitting the big RAMdIsk and the 8255 parallel port. For a full background on this story and details of Rodney`s ZX projects, check out Rodney Knaap`s Website where you will also find my original ZX97 article and schematic. Rodney has designed a single sided PCB for the ZX97L and also build and tested a prototype using this circuit. I have been unable to contact Rodney for a long time but I would urge you to try and contact Rodney for the latest CAD version of the ZX97Lite PCB. If you cannot get in touch with him, here are the beta version of the ZX97Lite single sided PCB ( ZX97LPCB - for 600pdi printer ), the ZX97Lite parts and jumper layout ( ZX97Lite Layout ) and my ZX97 EPROM file (ZX97L 27C256 EPROM binary image) While Rodney`s ZX97Lite schematic was a great improvement over my original ZX97 ASCII drawing, it is somewhat difficult to read because of the foreground and background colors, the dense layout, the bused signal lines, the IEC logic symbols, crowded pin numbers and in addition, it contains some minor errors and omissions In order to make the ZX97L easier to understand, I have redrawn the schematic by replacing the IEC logic with ANSI symbols, reformatted the drawing to black on white, renumbered pins and completed...
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: