Some people got success in Arduindo using an older mobile cable which works as USB/Serial converters. So you can read and write data as a serial port using pyserial.
On Tue, Jan 27, 2009 at 8:31 AM, Lie Ryan <lie.1...@gmail.com> wrote: > On Mon, 26 Jan 2009 11:08:48 -0600, Unknown wrote: > > > On 2009-01-26, Lie Ryan <lie.1...@gmail.com> wrote: > > > >> How about (a crazy idea) using the audio jack out? (DISCLAIMER: Little > >> Hardware Experience). High pitched sound (or anything in sound-ology > >> that means high voltage) means the device is on and low pitched sound > >> off. > > > > 1) Pitch has nothing to do with voltage. A high-pitch sound > > and a low pitch sound can have the exact same voltage. > > > > 2) The OP's device requires quite a bit of power. There is > > almost no power available from the line-out jack, and the voltage is > > limited to about 1V. If his sound card has a power-amp (none do > > these days), he might be able to get a usable amount of power. > > > >> The device will need an additional transistor to separate low voltage > >> from the high voltage. > > > > He'll need more than a transistor. He needs a power supply, some sort > > of rectifier/detector, and a comparitor. It would be more interesting to > > use notch filters to detect different frequencies so that you could have > > multiple output "bits". > > >From the little I know on electronics, a simple, single transistor would > (almost) immediately switch from on-to-off-to-on depending on the voltage > of the control pin (I think it was the middle pin). I was suggesting this > simplistic hack because as far as I comprehend the OP's need, he only > need on-off switch instead of a complex multiple output bits. > > >> I don't know how much power can be pulled from jack out, > > > > Almost none, and what's there is very low voltage. > > That's why the power is taken from USB port. > > >> but for a home brewn device it is still feasible to draw power from USB > >> and signal from jack out. > > > > It would probably be easier to buy a USB-parallel port chip. Then he's > > got power from the USB bus and something like 14 parallel I/O pins he > > can control. Alternatively A USB-serial chip will provide 2 outputs and > > 4 inputs. > > The idea was made on the basis that a USB microcontroller is not used. > Getting power from USB should be much easier than getting data while the > jack out can provide simple on-off signal. > > -- > http://mail.python.org/mailman/listinfo/python-list > -- Msc. Muriel de Souza Godoi Computation Department State University of Maringá Brazil
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