This is another project which fullfills a need. I once built a frequency counter using plain TTL chips. That was long before the CMOS HC versions, even before LS was available. It uses only 4 chips - 3 HC TTL`s and an Atmel At90S2313 microcontroller. It has a 5 digit LED display plus one used as a band indicator. Even with the LED display, the cur
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rent consumption is less than 50 mA. It counts up to at least 52 MHz. I couldn`t find any signal source in the lab that could supply more than 52 MHz, so it may go a bit higher, but the fClock(typ) for the HC590 is about 35-40 MHz, so you shouldn`t really count (no pun intended) on more. I got the idea from an article I saw on the net. I think it was a Circuit Cellar article. I had a look at the code, and it sounded like a quick and simple counter solution. I don`t know what chips it used, as I never saw the schematic, but here`s my implementation : A 8-bit "databus" is constructed from the lower 4 bits of PORTD and the upper 4 bits of PORTB on the 2313. This peculiar arrangement is necessary, as we need the OC1 output on PB3 for gating the counter stage. The displays are 3-digit 7-segment common-cathode displays. They are multiplexed by supplying the segment data from the databus, and selecting the current digit with a `HC138 dataselector, which is controlled by 3 I/O lines from the 2313. The two `HC590 counters are counting the input pulses and supplies the count to the 2313 on the databus. Each counter can be read separately using the OE_L and OE_H lines. The counters are cleared using the CLR signal. The counters are gated using the OC1 (Output Compare 1) signal from the 2313. By varying the duration of the gate time, the counter can be made autoranging, and handle a large frequency span. The software for the counter is...
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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