A couple of few years ago I had build a diode-sensor based RF powermeter using a 68HC11 microprocessor. Even before that I had build an analog RF powermeter with thermal power sensor. And I found datasheets of logarithmic amplifiers very interesting, that promised a measurement bandwidth of up to 2. 5GHz. When I had familiarized myself with the Atm
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el AVR microprocessor family, it was just a logic step to build myself a nice powermeter for all three measurement principles. So I did that and build a very small, battery powered powermeter with external power sensors. I called it UMD, the Universal Measurement Device. It was completely done with tiny surface mount components. Wanna see Click here for a picture. Or here for another picture. Here the UMD is measuring a beacon transmitter with the diode sensor. Unfortunately the device contained a few components that were very had to get (e. g. a mobile phone LCD display) and was so tiny that it was difficult to compare it with my documentation. I had changed the circuit a couple of times during the development, so I could not guarantee that my schematics were correct. When I was asked by some Belgian radio amateurs to write an article for their annual magazine, I decided to rebuild the circuit on a larger board with wired components and a standard 4x16 character LCD display. Lets call that version article-breadboard version. The breadboard was laying around for a few month until I decided that I should rather use it to build myself another power meter. Since I already had the UMD with the external sensors, I have included the sensors now in the meter housing. I had almost never used the log-amp sensor, so I went for a design with only two sensors: a diode sensor and a thermal power sensor. Since it was kind of a third...
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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