Quote:
Originally Posted by kinginthecastle
The results that I have had have been mixed, but here is some stuff that I found out.
Speed pulse is disconnected, sometimes, the video will show for a while, then it will go to map. Once it goes to map, it will rely solely on the sats to register speed. If I come to a stop, the video will show and if I drive it will go straight to map. So whatever is done to keep the video showing, must be done before it reaches this point. Even reconnecting the speed pulse will not reset the unit (although I did not reconnect it for a lengthy period of time).
I was using WileTundra's speed pulse generator that would keep the speed at between 0 and 1mph. I never saw it reach 2 mph. But with his speed pulse generator, I was never able to view the screen. I'm going to send the generator back to him, and he's going to try and slow down the pulse for me, to see if that will solve the problem. (I already tried to slow the pulse, and I think I might have broken the device).
So that's where we are at now...
|
A few points of clarification:
There are 3 possible signals you can feed into the NAV speed sensor:
- Factory speed signal from ECU - this will only allow rear DVD to play up front when you are completely stopped (and the emergency break has to be on too)
- No signal (factory wire disconnected) - the NAV will be fooled for short periods of time and let the video display up front but it soon realizes something is wrong due to the complete absence of signal so it resorts to using the GPS input, thus when you are moving it will switch to the map. This is exactly the same as my test results with the function lockout so it was predictable.
- Fake signal from my speed pulse generator device - I set the device to output a signal that alternates on the border between 0 kmph and 1 kmph (both always show 0 mph) because during my testing this was just the right level to keep the NAV functions enabled all the time while still allowing the map to scroll more smoothly. The device has a potentiometer which can be turned to speed the pulse signal up to 2-3 mph if desired but then the map scrolling might not be as smooth. I did not enable it to be slowed below 0 kmph because there was no need to.
Since my truck is a DC and I haven't used the rear DVD input yet, I didn't test the speed pulse generator with the rear DVD video function, although I am in the process of making another mod to enable full control over the rear DVD video input that will work for all truck models and I expect it to work just fine with my speed pulse generator. Details will be shared soon.
For kinginthecastle he wants to try an even slower pulse rate at or below 0 kmph which should be ok although I haven't tested that for any length of time since there was no need. I am going to change out a resistor on his device which will slow the pulse range down further and then he can experiment as needed.
It is possible that the video display uses different logic to detect motion but I doubt it - my theory is that the firmware has a single routine in the code that detects motion and it is used to control all function lockouts. king might have had inconsistent results due to the potentiometer setting on his device, or due to slight fluctuations in pulse rate based on variances in component tolerance, temperature, input voltage, interference, etc.
We will know for sure once I complete my mod to enable on screen video all the time. I hope to work on it this week.