Navigation Input Override (Speed Sensor Bypass)

[darkleafar]

I dont understand something - what happens if you simply bypass the speed sensor altogether? As far as I understand, dead reckoning only improves accuracy slightly - we wouldnt suffer any real consequences by simply by passing the speed sensor, would we?

Im saying because - In my mom's '09 Sentra, I had a TOMTOM ECLIPSE AVN4430 installed (http://www.eclipse-web.com/us/avn/avn4430overviews.html) and we simply bypassed the parking sensor and speed sensor, and it works perfectly fine. How is the Prius different?

[Manksgloob]

Because the Prius' navigation relies much more on the dead reckoning.

When you bypass the sensor, the navigation becomes HIGHLY inaccurate, to the point of being useless (for me, at least) as it displays your previous known location and updates every 30 seconds to 2 minutes, causing huge jumps in the map.

VERY easy to miss a turn that way. I recommend against doing this.

[Bilbrey]

I was talking to a service tech at the Toyota dealership, and he mentioned something about a software override for the NAV system. But when I asked him if he could do it for my 2010 Prius, he suddenly had to go get back to work.

"IF" such a software override is possible, I'd much prefer that to 'tricking' the speed sensor.

Of course, that means the driver would have to use the honor system and let the passenger touch the controls.

[hawkmoon77]

Originally Posted by Bilbrey

I was talking to a service tech at the Toyota dealership, and he mentioned something about a software override for the NAV system. But when I asked him if he could do it for my 2010 Prius, he suddenly had to go get back to work.

"IF" such a software override is possible, I'd much prefer that to 'tricking' the speed sensor.

Of course, that means the driver would have to use the honor system and let the passenger touch the controls.

Completely bypassing the sensor has no purpose. Without speed input, the carwill defalt to the GPS signal after 30 seconds or so. It will decrease accuracy an npt allow you input anything.

There is a software way to do it, theoretically. It is all software controlled. However, hacking the software and uploading new software into the system seems to be the much more agressive hack. Telling the system that the car is not going fast enough to lock you out interupts the normal system via one wire of input. A software hack would be substantially more difficult, would no doubt require special tools to implement, would likely require the same amount of disassembly... I don't know, seems like a lot to me.

[Bilbrey]

Originally Posted by hawkmoon77

Completely bypassing the sensor has no purpose. Without speed input, the carwill defalt to the GPS signal after 30 seconds or so. It will decrease accuracy an npt allow you input anything.

There is a software way to do it, theoretically. It is all software controlled. However, hacking the software and uploading new software into the system seems to be the much more agressive hack. Telling the system that the car is not going fast enough to lock you out interupts the normal system via one wire of input. A software hack would be substantially more difficult, would no doubt require special tools to implement, would likely require the same amount of disassembly... I don't know, seems like a lot to me.

Please don't get me wrong...
I think your solution is very creative and useful.
I also liked your auto headlight hack. (ordered the kit myself, thank you!)

But given the service tech mentioned there is supposedly a software mod, I hope it is only a matter of time before it escapes into the wild.

Also, I tend to overkill on projects I tackle and taking the 'difficult' route is normal for me...

[rachaelseven]

Originally Posted by brosnan

On the 2004, I found that substituting the speed signal with one equivalent to ~3mph allowed access while moving without triggering the secondary lockout. In that case the speed signal was a digital one and 4.7HZ from a TLC555 timer did the trick:
http://www.wb5mrn.com/prius/schemati...to_defeat5.pdf

If they've moved to an analog speed signal in the 2010, that would require a different technique, but perhaps the general concept would still work and make for a more convenient passenger "lockout override" switch (no need for repeated presses) like I had for the '04.

A similar solution seems to have been found for Tudras of that time period as well.

2007 Toyota Tundra Installation Report by WileETundra

The fellow even sells them assembled for those who don't like to solder. I wonder if the same technique/device would work on the '10 Prius NAV?

[hawkmoon77]

Originally Posted by rachaelseven

A similar solution seems to have been found for Tudras of that time period as well.

2007 Toyota Tundra Installation Report by WileETundra

The fellow even sells them assembled for those who don't like to solder. I wonder if the same technique/device would work on the '10 Prius NAV?

Very helpful. I do not like that the 12v+ source is basically unregulated (from 12 to 14). Considering that it feeds directly into the Nav, I think I'll throw in a 7812 voltage regulator and heatsink. It may be unnecessary, but it also can't hurt.

[rachaelseven]

Originally Posted by hawkmoon77

Very helpful. I do not like that the 12v+ source is basically unregulated (from 12 to 14). Considering that it feeds directly into the Nav, I think I'll throw in a 7812 voltage regulator and heatsink. It may be unnecessary, but it also can't hurt.

Glad that helps - I figure if you're going to do the prototyping, the least I can do is help with the research

[Orf]

Originally Posted by Bilbrey

I was talking to a service tech at the Toyota dealership, and he mentioned something about a software override for the NAV system. But when I asked him if he could do it for my 2010 Prius, he suddenly had to go get back to work.
"IF" such a software override is possible, I'd much prefer that to 'tricking' the speed sensor.
Of course, that means the driver would have to use the honor system and let the passenger touch the controls.

If the service tech is correct, surely he would be referring to a hidden system setting. The question is; How do we get into the hidden controls?

[hawkmoon77]

Originally Posted by Orf

If the service tech is correct, surely he would be referring to a hidden system setting. The question is; How do we get into the hidden controls?

I don't know. The diagnostic menu is accessible by holding the info button down while you click the headlight switch from off to parking brake 3 times. There does not seem to be a setting in there.