One of the many random devices I`ve found in my sometimes frightening basement was an HP frequency counter. The thing is built like a rock, still works perfectly and the manual contains full parts list, a complete circuit diagram and a description of the theory of operation. The counter is a 4 digit counter with. 1 or 1 second frequency intervals good to up to several megahertz
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and a nixie tube display. This last bit is what caught my eye. Nixie tube clocks, like binary clocks, are something of a staple of the tinkering community. The nixie tube provides a warm glowing warming glow not present in conventional LED based clocks, and just ooze retro-geek style. The downside of the nixie tube design is that it requires a large number of high voltage components which can be hard to get. The nixie tube counter has the driver circuit built in, and it occurred to me that I could set the clock to an arbitrary time by simply counting up. This also leaves me with a perfectly good (and potentially useful) frequency counter. The idea is simple. The first two digits are the hours, the last two are minutes. Every minute, pulse the timer and it will go up by 1. Every hour (when the time is, for instance, 11:59), send 41 pulses and the timer will count up to the next hour. Every 24 hours, count up from 2400 to 0000 and you roll back to midnight. Some counters have a reset function, so going from 2400 is just a matter of pulsing another port, but this counter would have required modification to be able to do that, and since it only has four digits available the count up method can be used to roll the clock to zero in about 2 minutes at 60hz. The implementation uses my favorite microcontroller, the ATTiny 2313. This uC has 18 general purpose I/O pins (14 more than required) and a "generous" 2k of memory. Complete...
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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