DIY: All NAV Functions All The Time without Firmware Downgrade!

[wileetundra]

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?

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.

[WT]

Originally Posted by wileetundra

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.

Yes I be very interested in hearing and seeing what pins you find that we can use to add an external DVD player so we can watch DVD on the stock nav unit. I am actually suprised there is not a wire harness from were the stock overhead dvd player location to nav unit is that allows you to watch the dvd on the nav from the stock overhead dvd player. I was going to poke around the top were the stock dvd player would be some but just have not found time to do that yet.
Well I look forward to hearing what you have in mind or what your ideas are.

[wileetundra]

Originally Posted by WT

Yes I be very interested in hearing and seeing what pins you find that we can use to add an external DVD player so we can watch DVD on the stock nav unit. I am actually suprised there is not a wire harness from were the stock overhead dvd player location to nav unit is that allows you to watch the dvd on the nav from the stock overhead dvd player. I was going to poke around the top were the stock dvd player would be some but just have not found time to do that yet.
Well I look forward to hearing what you have in mind or what your ideas are.

I already hacked into the rear camera input and connected it to a video sequencer so I can display my choice of 4 video signals on the NAV screen at any time. I am using this to add two blind spot cameras which come on with the turn signals, and also to play a portable DVD on the dash screen while the player is mounted in the center console. The only drawback is that the NAV displays the stupid "check surroundings for safety" text on the bottom of the screen when you use the rear camera input so I am going to tap into the other video input as well and use it when I want to watch movies. I am just finishing the camera install now and will add the additional video circuit soon, then post all the details with pics and video on my mod site when done.

[WT]

Originally Posted by wileetundra

I already hacked into the rear camera input and connected it to a video sequencer so I can display my choice of 4 video signals on the NAV screen at any time. I am using this to add two blind spot cameras which come on with the turn signals, and also to play a portable DVD on the dash screen while the player is mounted in the center console. The only drawback is that the NAV displays the stupid "check surroundings for safety" text on the bottom of the screen when you use the rear camera input so I am going to tap into the other video input as well and use it when I want to watch movies. I am just finishing the camera install now and will add the additional video circuit soon, then post all the details with pics and video on my mod site when done.

Great work !
I have been following your posts and web page with what you have all done so far, so I will keep looking back at it now and then and look forward to the new input mod.

[kinginthecastle]

after fiddling with it for days, I've come to the conclusion that it may not be possible to watch dvds on the nav screen while the car is in motion. The results have been variable, but from what I can see, it may not work. Right now, i've simply got the speed sensor disconnected. When I am at a full stop, the screen works, but as soon as I drive the car at all, the screen disappears. At one point, I was able to get the screen to show while driving for a few miles. But then it would disappear.

[ag4ever]

Originally Posted by kinginthecastle

after fiddling with it for days, I've come to the conclusion that it may not be possible to watch dvds on the nav screen while the car is in motion. The results have been variable, but from what I can see, it may not work. Right now, i've simply got the speed sensor disconnected. When I am at a full stop, the screen works, but as soon as I drive the car at all, the screen disappears. At one point, I was able to get the screen to show while driving for a few miles. But then it would disappear.

So the nav uses the data from the sats to determine if the video feed can be played, but uses the vehicle speed sensor to determine if the functions should be locked out?

Have you tried the speed pulse generator with a low pulse rate to determine if a simulated 1 mph signal will fool it into leaving the video displayed?

[kinginthecastle]

Originally Posted by ag4ever

So the nav uses the data from the sats to determine if the video feed can be played, but uses the vehicle speed sensor to determine if the functions should be locked out?

Have you tried the speed pulse generator with a low pulse rate to determine if a simulated 1 mph signal will fool it into leaving the video displayed?

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...

[hamm3r]

ag4ever,

Thanks for the variation using an etched PCB. I just picked up my PCB kit from Radio Shack and hope to get to this project in the next few weeks.

I have some questions for you:

1. Are you still using the original design which includes the output capacitor? I am considering either modifying your etch or just connecting the toggle wire directly to where the capicitor would have gone.
2. Did you find the large heat shrink and if so, are you pleased with it?

[wileetundra]

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:

1. 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)
2. 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.
3. 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.

[ag4ever]

Originally Posted by hamm3r

ag4ever,

Thanks for the variation using an etched PCB. I just picked up my PCB kit from Radio Shack and hope to get to this project in the next few weeks.

I have some questions for you:

1. Are you still using the original design which includes the output capacitor? I am considering either modifying your etch or just connecting the toggle wire directly to where the capicitor would have gone.
2. Did you find the large heat shrink and if so, are you pleased with it?

I am using the original design with the output capacitor. Unfortunatly, I have installed it in my Camry, but it is not working yet. I have not gone into the diagnostic screen to see if I have the correct speed when the SPG is activated or if there is some other difference in the nav since my Camry is a Hybrid. There might be some data that comes from the can-buss in lieu of the wires, but I doubt it.

Here is a picture of the wiring to the camry's nav.



The twisted wires (red, black, black, white) are for adding a backup camera to the camry. Also note that the speed pulse wire is purple in the camry. Also there are three wires in this plug whereas the Tundra only has the green and white wires.



In the second picture you can see where the wires are all routed from behind the center stack. I have tucked the wiring between the carpet and the plastic with just the switch sticking out. I can reach down next to my leg and flip the switch easily.

I did find some 1 1/2" heat shrink at Fry's. (Did not have a chance to get by EPO and I bet they would have had the desired 1 1/8" size). But the 1 1/2" size is working out perfect. It protects the wiring and allows easy access if I need to work on the board.

[Jer]

Let me know ASAP as I'm interested in if this works for my TCH as well.

[hamm3r]

Originally Posted by ag4ever

I am using the original design with the output capacitor. Unfortunatly, I have installed it in my Camry, but it is not working yet. I have not gone into the diagnostic screen to see if I have the correct speed when the SPG is activated or if there is some other difference in the nav since my Camry is a Hybrid. There might be some data that comes from the can-buss in lieu of the wires, but I doubt it.

Shucks. I didn't realize that nobody has tried it in the Camry yet. Well, I have my kit and my Staples photo basic "gloss" paper and am ready to etch. No time just yet, but I am accumulating parts.

Any idea if there are any sort of "piggyback" connects that can be used to clip the thing into the Camry harness instead of tape or wirenuts, etc?

[ag4ever]

You can not "piggy back" it since you need to sever the vehicle's speed pulses and substitute the SPG signal.

[hamm3r]

Wile's instructions say: "Red wire from the speed pulse generator circuit: any +12 volt source that is switched on with the ignition"

I'm still not far along but I'm just curious what you are using for your power source?

[kinginthecastle]

I connected it to the power that goes to the back up camera.