In 1991, I was very interested on this display but I can`t find one in the town and expensive to import from abroad. But now, it`s everywhere and I can say that this technology is obsolete since the colorful TFT display is easy to find and cheap. The mcu is AT89S51/52, connected to a 128x64 graphic LCD and time keeper DS1302. Many manufacturers pr
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oduce this LCD so be careful of differentpinout, refer toits original datasheet. DS1302 with trickle-chargeable to charge the backup battery connected to it, in this project I use a 1F/5. 5V. Yes, one Farad capacitor. After weeks charged, I test the backup function by disconnecting the power supplyfor a month, hohooo the time is still correct and continuously counting. So if you want to safe a little money, I recommend you to use smaller capacitor like 0. 47F or 0. 33F. The crystal quality for DS1302 is very substantial, the small frequency error will lead to accumulated time drift. Pull up resistors area must, you`ll face a strange circuit behaviour if not installed. Need USB solution for your project Use LPC2148 MCU. In old days it`s very handy using LPT or COM to interface your project to PC but today they are vanished just like dinosaur. All switch status can be monitored on the PC, as well as the ADC value. The LEDs are turn on/off by the first byte sent from PC. In my project input and output buffer size are 4 bytes each, you can increase the buffer depends on your need. To me, this project is about perfect because the program on PC can recover the connectionwhen temporary USB cable disconnection occurs. The VB program recognize the device from its Vendor ID (C251) and Product ID (1301). Thiscircuit work onpoll-based communication, meaning theMCU will reply when receive request fromPC. So when USB disconnected, there...
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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