The result was a project that includes a waveform capture circuit, a graphic LCD (Liquid Crystal Display) and a control panel with LED indicators. As described, the display plugs directly into the waveform capture and control unit, which is what the what the rest of this page is dedicated to. The control panel controller appears as an ASCII terminal to the waveform capture controller and the two chips communicate using their on-chip hardware UARTs at 9600 baud. Both the controllers are Atmel AT90S2313. The control controller could have been implemented using an AT90S1200 but it was a little easier with the AT90S2313 because it has a hardware UART and a luxurious RAM stack, and by the time I came that part of the project I was much more anxious to see waveforms than to see if I could use the lower cost processor.
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The board contains all of the analog circuit including the +5 volt power supply as well as the waveform sampling circuit and control panel interface with LED display. A clock display picked up surplus is used to display the sampling rate and it is driven by the control panel controller. A separate LED mounted just below the clock display indicates that the sampling is being triggered and is driven directly by the analog circuitry.
AC coupling through the two 0.33 uf capacitors in series gives a time constant on the input of about 2 seconds -may be a little long for some applications. The easiest way to shorten it is to replace the series capacitors (there are two of them because the ones in this range that I have on hand are tantalum) with a nonpolarized capacitor with a suitable voltage rating.
The 10: 1 divider on the input circuit is frequency compensated with a single 5 pf capacitor to ground. I used parts I had on hand. If you are picky, you can use metal oxide resistors to get a more precise and stable divider, but remember this is only a 6 bit waveform monitor.
The ideal case when the divider switch is in the "X1/10" position is for the capacitance across the 10 Meg Ohm resistor to be 1/10 the capacitance from the top of the 1 meg Ohm resistor to ground. A good practice is to place a relatively large resistor from the top of the 1 meg resistor to ground, say 10 or 15 pf, and then select or adjust a trimmer...
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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