The four 1K resistors on the output of U6 are too high in value for some parallel ports. Change these to 100ohm. Some LSI based parallel ports use active pull-up resistors and these are lower than the nominal 4K7 which causes a voltage divider effect. A bad design mistake.
The eight LED dropper resistors are too low in value and cause pikes on the power rails which can effect the rest of the circuit. Change these resistors to 1K or greater. Another bad design mistake.
There is a new modification in the Jan 2000 issue of EA that describes a hardware modification to support EPROM's up to 1Mb. Whilst my software can cater for sizes up to 16Mb, I have no idea if this hardware modification is compatible with my software, and I have no plans to try it myself or even look into it conceptually, nor update my software to support it.
In my humble opinion the whole design is WAY past it's used-by date (even was back when it was published) and needs a complete redesign, not just some ad-hock upgrade to an already unreliable design.
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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