This instructable will show you how to build a portable Touch Screen
Oscilloscope for less than 40 U$!

The oscilloscope is one of the most powerful electronic instruments that
is available to electronics hobbyist, experimenters, and engineers. It is
mainly used to measue time-varying signals. Any time you have a signal
that varies with time( slowly, quickly, and /or periodically ) you can use
an oscilloscope to measure it , visualize it, and to find any unexpected
features in it.

We can use an oscilloscope to observe and study signal characteristics
that we could otherwise not see .

You will learn about the Arduino mega analog to digital converter( ADC).

We will be using the Arduino analog A0 input to sample and capture time
varying signals by Writing a program that will also display those signals
in a 3.8" TFT LCD touch display, and we will input data to modify the
oscilloscope behavior, using the touch capabilities of the screen display.

Before we start building and programming, lets review some basic
characteristics of an oscilloscope.

These are functions you can control on most oscilloscopes:

Sweep speed. Sweep speed is usually measured in units of time per distance,
like milliseconds/centimeter or milliseconds per division.This might also
be referred to as the horizontal sensitivity.

Vertical sensitivity. That's the measure of how sensitive the display dot
is to voltage applied to the input terminals. It is usually measured in
volts/centimeter or volts per division.

A trigger signal can be generated when the signal value reaches some
particular level - the trigger level. In most cases you can set the trigger
level to a voltage value of your choosing. A trigger is used to capture and
stabilize the waveform on the screen, or to wait for an event before
capturing the data
The oscilloscope, like my 4 channel DC DVM, will not be as accurate as
a commercial unit, but it works pretty good for low voltage and low frequencies.

Step 1: UPDATE: Sketch to convert Oscope to 3 Channel DVM with graphic display + Lego enclosure

Thank you to all who voted for me! This Instructable won 3rd prize in the Arduino contest, and first prize in the Gadget contest...

Included are pictures and code to convert your oscope to a 3 Channel DVM and to show the output of each channel individually in the scope display by pressing a soft key on the display. ( the third button from the top)

you will need an L shaped female pin connector if you want to have the flexibility of inserting jumpers, otherwise, just bend the pins on one side of the jumpers to insert them in the analog channels (A0- A3) to use them as your probes.

Just download the sketch and upload it to the Arduino.

You can label each channel individually, just change the wording in the sketch.

I have also made a lego enclosure for the scope..check out the pictures.

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More by johnag:  Arduino  DEMO series Make an Oscilloscope Using the SainSmart Mega2560 with the TFT LCD shield and the 3.5 "color touch screen Make a Mini Arduino programmable  4 channel DC-DVM
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