Circuit Fear not, dear reader - I haven`t given up the sauce. I am not in withdrawal, suffering severe autonomic instability. I refer not to Delirium Tremens, but to time differences, dt. Specifically to the `DT` data column in the WSPR GUI. Everything was going FB with the multi-mode beacon and its new internal DDS until Thursday, when I started
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to notice large (and apparently random) timing errors. You can see the fall-off in performance on Thursday in this plot of the number of spots in each 24 hour period over the past two weeks. Eventually I discovered it was caused by some kind of interaction between the new Controller board and DDS and the main VXO system. The interaction was either conducted through ground, power lines or interface lines or through radiation from clocks, RF sources etc. Whatever the cause, simply un-plugging the controller (and reverting to the SDR Kits USB synth ) has cleared up the jitters for the moment. I had so much fun with building the DDS board in surface mount technology that I decided to stick in the nano scale and got some tiny tactile momentary action switches from Farnell (seen here against a PIC 16F873 for scale). . a conventional layout in which columns of switches are sequentially pulled low by pull-down transistors (in this case MMBT3904s - the surface-mount version of my beloved 2n3904) and read in "rows". I arranged two columns of three switches - four "arrow" keys to navigate up/down, left/right and two (as yet) un-designated switches. The actual software interface to the keypad is simple enough - the only real issue being the optimisation of the delays and rules for switch de-bouncing. I tested for two consecutive valid "reads" of the same key, separated by a small delay and then imposed another delay before looking for...
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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