i'm looking for a solution to connect the arduino with a slideshow. there are 3 questions on the slides and only 1 right answer is possible. if the right input is buzzert, only one output switches to 1. that all...
the problem is, when will the arduino know that the right input is triggert?
The Arduino sketch consists of a setup() function that is called once, and a loop() function that is called in an infinite loop. With a 16MHz crystal, loop could be called millions of times per second, providing you don't do anything to appreciably slow it down like analogRead(), Serial.print(), or (worst of all) delay().
Your question is a bit confusing. Each slide has 3 questions, but only one right answer. I presume you mean that each slide has one question, with three possible answers, only one of which is right.
I also presume that the Arduino has 3 switches connected to it, each of which "selects" an answer. Using digitalRead(), you can read the 3 pins that the switches are attached to, each pass through loop. Since the user will presumably only press one button, and there aren't race conditions, this ought to happen fast enough to appear to the user as instantaneous, even though the Arduino may have done several thousands of other things before recognizing that a switch was pressed.
Once you know that a switch was pressed, and which one it was, you will somehow need to communicate that information back to the PC, and do something with it there.
How do you propose to do that? Powerpoint has no ability to read from the serial port that I know of.
Triggering a digital output might not be sufficient. The PC can't tell that you have done that, so it won't have accomplished anything.
There is a library called GoBetwino that allows you to send data to some Windows applications (if you are using a Windows O/S). You might be able to send data to Powerpoint to make it do something.
The relationship between Powerpoint and the Arduino is not clear. Is the Arduino going to keep track of right vs. wrong answers? How will it know which is the right answer?
First off, you need to explain what you want to have happen if the user gets the answer right. Can you make Powerpoint do that somehow, if the user is pressing buttons on the PC?
Then, you need to explain what you want to have happen if the user gets the answer wrong. Can you make Powerpoint do that somehow, if the user is pressing buttons on the PC?
If you can make Powerpoint respond correctly when the user presses buttons on the PC, then, you may be able to make the Arduino send the right data to the PC, using GoBetwino, to make Powerpoint think that a button on the PC was pressed.