The clock shows time in 5 minute intervals. The hour and minute can be set. There is no alarm or any AM/PM indicator. For the clock face I used a 2 pieces of lenolium glued together to increase thickness. (A couple of floor tiles would work as well. ) The numerals are just inexpensive adhesive characters I purchased at a hardware store meant for us
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e on mail boxes. The LEDs are glued to the clock face from behind. If you wanted to get fancy, a nice brass or wooden clock face can be made along with a wooden cabinet like a "grandfather" style clock. NOTE : In the following schematics, TTL devices are shown as 7400 series. These are used as generic 7400 series part numbers. During construction, 74LS, 74ALS or 74HCT should be used because of the low power requirements and availability. (I know most of you know this already. ) The power supply is not shown in the schematics. A simple 5 volt regulated supply of 500mA to 1A will work well. I used a 7. 5V, 600 mA power transformer, a full wave rectifier and a 220 uf capacitor as a filter. Regulation is done with a LM340-5 - a 7805 would work just as well. For the full wave rectifier, I used a rectifier set in a TO-220 package that I salvaged from a switching power supply. The oscillator is a LM311 comparator along with a 32768Hz tuning fork type clock resonator. The 10pf trim cap is adjusted using a 6 digit frequency counter with the resolution of 1Hz. If you don`t have a 6 digit frequency counter, a fixed capacitor of 5 to 7 pf should get you close. I chose the LM311 circuit because the 311 is commonly available and inexpensive. There probably are better time base ICs available. The 32768Hz signal is divided by 16384 to get a 2Hz signal. This is done with a 74HCT4020 counter. The 2Hz signal is then divided by 12 with a 7492,...
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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