This is a successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876. The later is capable of driving 4 digit LED display in multiplexed mode while measuring fr
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equency, power supply voltage as well as handle two analog inputs to display SWR/PWR signal strength in a bargraph manner. There is no need for external LED display driver chip as well as external data EEPROM since it is already implemented in PIC16F876. Reduction in the number of used chips also results in smaller dimensions of the counter compared to its predecessor. Measurement of the input voltage at two analog inputs, simultaneously displayed as bargraph (PWR/SWR or S) indicator. The input sensitivity could be chosen between 0. 25V, 0. 5V, 1. 0V and 2. 0V for maximum bargraph indication. Power save mode: Automatic display shut-down in case the push-button action or frequency change does not occur for a certain time. Display switches on againt after frequency change or push-button action. The available shut-down time periods are 3s, 10s, 30s, 60s, 120s, 180s and 240s. This function can be disabled in set-up menu. Programmable frequency offset added or subtracted from measured frequency, settable in the range of 0 to 99, 999. 9 kHz. This is convenient for use with heterodyne type of RX/TX In operating mode a push-button allows the user to choose between the frequency, bargraph or supply voltage to be displayed. The frequency display mode can also be changed with longer (>1s) push-button pressing. For example if the frequency to be displayed is 14. 065. 9 MHz the user will see on the four digit display either "065. 9",...
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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