Electroons.com - Electronics & uController Info

This is a very interesting project. You all must have played the game “Duck Hunt” in video game . Here is a circuit that let you play the same shooting game but now the display device is not your television while it is a C.R.O. that is Cathode Ray Oscilloscope.

Now come to the concept part of the design. The basic building blocks of the design are ATmega32 (Atmel AVR Family), an Digital to Analog convertor, and a CRO.

The circuit above is a simple R-2R ladder type of Digital to Analog Converter. It has total 8 inputs as digital word input and an analog output from Op-Amp LM358.

The basic control of signal is provided by the controller i.e. ATmega32. mega32 generates digital output from two of its ports which in turn converted into analog voltage using a pair of DAC’s.

In our case we have used buffers to couple microcontroller’s output to the DAC input, this is because while doing experiments we were facing some problems because of unbalance in the R-2R ratio of DAC circuit. Now buffer properly isolates the microcontroller output to the DAC input.For buffer we used 74HCT541 IC you can go for some other also.

To couple the analog output from DAC to the CRO input we used MIC 50ohm cable, and ofcourse CRO needs BNC connectors for input. The most important thing is we are using CRO display in X-Y mode of operation. Each of two DAC generates analog signals corresponding to X and Y input respectively.

Download Complete source code for AVR compiled using WinAVR