Arduino - Trying to keep a pin high, but it's not working

Question

I'm building a small robot that uses a relay to power the motors. To run the relay, I have it connected to pins 11 and 12. If I use something like the Blink example, where it turns the pin on, then off a second later, it works fine. However, what I'm trying to do is keep a pin on until an IF statement is met. When I run it, it turns the pin on for a millisecond or so, then off permanently. How could I get this to work?

Answer 1

Well, I have a couple guesses, but your description is vague without knowing what the IF statement is...maybe it is being met somehow without your knowledge.

I am pretty certain the light is staying on longer than a millisecond in order for you to see it. As a side note, here is an interesting, related article: http://www.100fps.com/how_many_frames_can_humans_see.htm

Are you debouncing? http://arduino.cc/en/Tutorial/Debounce

I can imagine a simple program with an IF to count button presses -- or the timing of -- where, without debouncing, you will meet the conditional without it seeming correct.

This is just one possibility, but without knowing the code, or the setup it's hard to say.