Hi, Christan Klippel has made the CVBOX interface: 88 channel AD converter with 8, 10 or 12 bits of resolution. Connects to the parport. Schematic, circuit boards and externals for Pd (Linux/Win), jMax and Max (Win) available online. Try: http://www.nullmedium.de/dev/hardware/cvbox.html
Christian also is working on a USB version but I don't know when this will be finished.
Olaf
"B. Bogart" schrieb:
Hey Johannes,
Have you heard of the AID project? (www.interaccess.org)
We're making a GPL PIC16F877 based general sensor platform for artists in particular. We already have 8 channels AtoD, 2 PWM ports, I2C and a 8bit bus to communicate with up to 16 digital "peripheral" cards. Its got only Serial interface for now, but we're working on USB as well.
I've also started a suite of control abstractions for PD, based on the comport and ascii externals.
We're always looking for help (especially in programming- we're using hitech C) Please jong the mailist or drop me a line if your interested in contributing.
Ben
----- Original Message ----- From: "Johannes Taelman" Johannes.Taelman@UGent.be To: "Chris McCormick" chris@mccormick.cx Cc: pd-list@iem.at Sent: Saturday, November 01, 2003 5:59 PM Subject: Re: [PD] Sensors
On Fri, 31 Oct 2003, Chris McCormick wrote:
Hi,
An idea I had recently (though I'm sure it's not original) is to hook up 8 555-timer circuits with variable resistors to the parallel port and poll it periodically to figure out the frequency of the 8 squarewaves on individual parallel port pins. These frequencies could be used as control values in a Pd patch. The advantages are that 555 timer circuits with a variable resistor are very cheap, and simple. Your range would be from where frequency updates are too far between (let's say 100Hz) to the upper-range of the parallel port polling frequency. So if you can poll it at 8000Hz you would probably want to stop at nyquist to get meaningful updates let's say at 4000Hz (not quite certain that nyquist is relevant here though).
How about timing the pulse width (from the capacitor discharges) directly, instead of counting the frequency? The legacy joystick port works this way (also using polling).
Still, if you want to build your own sensor-to-pc interface, I think using a microchip PIC microcontroller (on serial port, on a MIDI port, or the USB-series) for analog inputs is a more elegant solution. It requires the use of a programmer once though, but those are not expensive either. It is less components, less handwork, less CPU cycles wasted on polling, and more resolution. Have a look at www.ucapps.de for a well-documented and free design.
I started messing with those chips a couple of months ago, and I'm pleased with them. I've programmed them for analog-to-midi, as a 12-channel infrared-light-barrier-controller and as multichannel pulse generator.
regards, j#|@
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