astronomerroyal
New Member
Hi,
I'd like to use my ipod as a simple 5v pulse generator. The idea is to create audio files that are played on the ipod, the analogue output from which is then processed into simple square 5v pulses that can then be feed into a microcontroller. For example, if I play a 100HZ audio tone, it gets turned into a 100Hz stream of square 5v pulses.
My analogue interfacing skills are essentially non-existent, nevertheless I looked at the ipod's audio output signal across a 30 Ohm resistor and saw that the amplitude of the voltage was only +/- 200mV. All I want is a way to get the peaks to generate a 5v signal and the rest 0v, a sort of 1-bit digitization.
Would a comparator with a ~100mV reference voltage be suitable, or should I amplify (and possibly rectify) the audio signal first? I did play around with an LM386 opamp (the only opamp I have) and a LM2903 comparator, but felt that perhaps I was missing the simplest solution.
I'm a bit confused about my ipod's small output amplitude of +/-200mV, since this *iphone* `signal generator' app suggests an output amplitude of a few volts is possible.
**broken link removed**
Here's a pseudo-schematic,
I'd like to use my ipod as a simple 5v pulse generator. The idea is to create audio files that are played on the ipod, the analogue output from which is then processed into simple square 5v pulses that can then be feed into a microcontroller. For example, if I play a 100HZ audio tone, it gets turned into a 100Hz stream of square 5v pulses.
My analogue interfacing skills are essentially non-existent, nevertheless I looked at the ipod's audio output signal across a 30 Ohm resistor and saw that the amplitude of the voltage was only +/- 200mV. All I want is a way to get the peaks to generate a 5v signal and the rest 0v, a sort of 1-bit digitization.
Would a comparator with a ~100mV reference voltage be suitable, or should I amplify (and possibly rectify) the audio signal first? I did play around with an LM386 opamp (the only opamp I have) and a LM2903 comparator, but felt that perhaps I was missing the simplest solution.
I'm a bit confused about my ipod's small output amplitude of +/-200mV, since this *iphone* `signal generator' app suggests an output amplitude of a few volts is possible.
**broken link removed**
Here's a pseudo-schematic,