Scope clock has two modes of operation
• Analog clock Mode – This is the default mode of operation . When the arduino is reset an analog clock appears on the oscilloscope screen .It keeps accurate time using clock hands.
• Temperature Mode – This mode of operation displays the current temperature of the surrounding .
The mode is controlled by a push button . On pressing and releasing the pushbutton an interrupt is generated which changes the mode to Thermometer which displays the current temperature of the surrounding . After a few seconds the mode changes to analog clock
Step 1: The D.A.C
Due to cost and the need for matched components, DACs are almost exclusively manufactured on integrated circuits (ICs). There are many DAC architectures which have different advantages and disadvantages. The suitability of a particular DAC for an application is determined by a variety of measurements including speed and resolution. Depending upon the requirement we can use a 2 or more bit resolution DAC .
Although many types of DAC configuration are available ,an R-2R Ladder is the simple and inexpensive way to perform Digital-to-Analog conversion, using repetitive arrangements of precision resistor networks in a ladder-like configuration. In this project we have used two 8-bit R-2R ladder formations two convert the digital signal from the arduino into analog form and these are fed to the two channels of the Oscilloscope .
The DAC`s are soldered on the arduino protoshield along with temperature sensor circuit , connections of the two DAC with pins of arduino are shown in schematic
In our project digital pins D2-D9 are used in DAC1, digital pins D11-D13 and analog pins A1-A5 are used in DAC2 .