Posted by ashraf (212.103.162.149) on February 23, 2001 at 16:34:46: Dear sir I am so intersected with your web sit and the information on it Sir I have an application - wish if u can help me on it I use mpeg2 movie on pc screen I wish if I can make some effect in the room like wind smoke rains ,,,, etc So do u have some idea how to reprogram this and generate pulses from serial or parallel port of the pc � should I use D/A board ? � can I get this pulses ( 5v) through the joystick port ? thanks and best regards ashraf mansour : Dear sir : I am so intersected with your web sit and the information on it : Sir I have an application - wish if u can help me on it : I use mpeg2 movie on pc screen What software application are you using to view that on screen ? And on what operating system you are working on ? : I wish if I can make some effect in the room like wind smoke rains ,,,, etc : So do u have some idea how to reprogram this and generate pulses from serial or : parallel port of the pc If you need only on/off style controlling, then PC serial/parallel ports can be useful. Usable ideas can be driving set of relays from parallel port and use that to control whatever equipment (relay turns on mains power to light/fan, relay contact repaces temote control button, relay switches +10V to 0-10V control input of equipment etc.) I have used this kind of idea to activate lighs, foggers etc. from PC parallel port with my own software running on DOS and Linux systems. If you need just pulses to activate something like triggering a stroboscope, a serial port might be a working idea. Serial port with some register level hacking can be used to provide three on/off type outputs if needed. I have some examples on those techniques take a look at following web pages: http://www.hut.fi/Misc/Electronics/circuits/parallel_output.html http://www.hut.fi/Misc/Electronics/circuits/strobo_rs232.html : � should I use D/A board ? If you need proportional control like 0..10V analogue control (for exampel for controlling light level on 0..10V controllable light dimmer) then you need a D/A board. If you just need on/off type controlling, you do not necessarily need any D/A board. Byuing a D/A baord might be waste of money unless the software which comes with it is otherwise usable to do things you need easily. : � can I get this pulses ( 5v) through the joystick port ? The PC joystick port is designed to be just an input port by the design. So trying to use it as an output device is like trying to do things in the very hard way. The fact is that joystick port can output signals in two ways: there is nowadays MIDI port integrated to practically all joystick ports (it is essentially a serial port with input and output) and it is possible to detect when joystick position is read by looking at how much current is taken from joystick port through the potentiometers (the current is highest just in the beginning of joystick position reading). The MIDI port is usable for some applications, using the second method is not much of use for anything very usable or creative. For more joystick port information take a look at my joystick port documents at http://www.epanorama.net/documents/joystick/index.html : thanks and best regards : ashraf mansour First you need to get the �nterfacing idea ready and the get to figure out how you can sync the other actions to the MPEG movie playback. Basicly you need some kind of software to time the other actions to the movie playback. I don't know any player which could time some other actions (like running some script or other program) on specified time during MPEG playback (timed to movie time code). Anyone has tips for this ? Other option is to write pa program which first starts the movie playback as separate process, then waits for a predefined time, then activates whatever needed, waits for next action, starts it etc. If the timing accuracy of the effect does not need to match very accurately to the movie, this might not work, because there can always be some unexpected differences in the program timing and the movie playback (multitaking can sometimes cause movie playback to slow down etc. so the timings might slip..). Depeding on the application this might be acceptable or not. If no other options to do things, try this.
