I am currently working on a project that I need an adjustable voltage (3V, 3.5V, 4V, 4.5V) to feed in to the reference voltage input of the comparator. See the circuit diagram below.
I was surfing the forum and the playground from the Arduino website, there are few ways I can
achieve the DAC from the Arduino.http://arduino.cc/playground/Main/InterfacingWithHardware#adcdacUsing OpAmphttp://www.avdweb.nl/arduino/simple-10-bit-dac.htmlR/2R Ladderhttp://blog.makezine.com/archive/2008/05/makeit-protodac-shield-fo.html?CMP=OTC-0D6B48984890Here are my problems.
1) Which method do you recommend for my application? R/2R Ladder or the one using the op amp?
2) Can the ADC output an DC voltage (0 to 5V) ?
3) Am I using the PWM output pin to achieve the process of DAC?