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can i use the blueberry trackball for my psp phat?
how will i know which solder points am i going to solder on?
i made you funny huh...
so do you know where the solder points?
nico had a trackball that didnt put out analog or used infared at all, his had two switches that would be set ff my the trackball. they were supposed to sell them at the shop but that never happened, they were also supposed to have a breakout board so you werent soldering onto .5 milimeter slits of copper, alas no results there, i was planning on using one in my psp since i play lefty i use the analog to aim. nikolai, im somewhat interested in doing this to my one ps2 controller, i dont have much room inside since it has my shocker mod but if you can send me a parts list via pm ill gladly give this a shot.
NikolaiK's explanations of the trackball's operation are very good. I'm going try to elaborate a little and save NikolaiK a little time in translating (I'm not that great at explanation so bear with me). The speed at which the wheels (x wheel and y wheel driven by trackball) are moving is proportional to the frequency that the phototransistors pick up. The speed is our desired unit and the frequency is our given. The frequency that the phototransistor picks up is a square wave signal of logic 0 and logic 1 (when it detects light and when it doesn't). Technically, this is a pulse-width modulated (PWM) voltage signal. Since PWM signals are composed of only the maximum and minimum values (square wave), the ratio of the length of time when the signal is at maximum to the length time of the period (or what's called the 'duty cycle') is used to describe it. Basically, if you have a PWM voltage and want to make it an analog voltage, just take its mean. This can be accomplished in-circuit with low-pass filtering. Check out some detailed info on low-pass here:http://www.ontrak.net/pwm.htmI was a little baffled at first though, how can you figure out which direction the wheels are turning in (in other words, if the wheels' speeds are negative)? Apparently, trackballs use two or more phototransistors per wheel. Check out this site for more information on that.http://www.4qdtec.com/meece.htmlThe thing is, you'll probably want to check which of the two phototransistors goes high first with some interrupts. (and you'll definately want to have this checking to happen in the circuit before signal goes through the low-pass filter.)Hope that made sense and/or helped.