INTERACTIVE DIGITAL MEDIA TECHNOLOGY
Cruft Fest 2014 – Pioneer RS-B655 Project
For Curft Fest 2014 I turned a Pioneer tape player in to digital to analogue converter, sort of.
The converter is based on the R/2R design.
The R/2R DAC is a very simple concept that can
bring good results when implemented properly. It uses 8 potential dividers
connected in series with each input connected to a digital output of the
Arduino. Each digital pin can give an output of either 0V or 5V, when connected
in this resistor network the Thevenin resistance of the resistors give an
output voltage depending on the number of high (5V) inputs. In this case I have
built an 8-bit DAC so the possibly output voltages are 0V - 5V in 0 – 255 steps.
We can then use the byte number in our code – B11010100
= Byte 212
The following diagram shows the final circuit of the project and was built onto perf-board and
fixed to the original tape machine circuit board.
The following pictures show the output of the DAC pre and post filtering. The error in the conversion is clearly visible but the pictures show the importance of filtering digital outputs.
For an Interactive Digital Multimedia Technology module I think it was the wrong project. But lessons were learned and I look forward to the next project to show a more creative side of my skills.
Charlie Slee
