Quote:
Originally Posted by kinginthecastle
is it possible to adjust the timer on the speed pulse generator or perhaps use a timer that creates slower pulses?
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You can use a higher resistor in place of the 33k ohm resistor, which will increase the total resistance and thus slow down the pulse rate further. I initially experimented with resistance values from 0-300k ohms but anything over 150k-200k ohms was too slow and I was worried that the NAV unit wouldn't recognize the pulse consistently.
My current circuit design uses a range of 33k-133k ohm which is adjustable with the potentiometer. This gives me a range of between 0-3kmph on the NAV diagnostic screen and the pulse remains steady. I set all of my devices to the 0-1kmph by default since the NAV map scrolling seemed to be the smoothest in this mode. Any faster and the NAV unit might intermittently lockout the functions as you approach 4-5 mph, plus the map scrolling is much worse and less accurate.
To watch DVD all the time on the front unit you would want to slow the pulse down just a bit so it always reads 0kmph, so try replacing the 33k ohm resistor with a 47k ohm resistor and see if that helps. I don't have a rear seat DVD system in my DC so I can't test it but I plan to hack the unused video input circuit on my NAV soon to gain even more video inputs than I already have. I suspect that a pulse of once every 2 seconds should do the trick but only testing can confirm. The other option is just to flip your switch back to the factory mode, then the rear DVD will display on the front when you are parked as designed.