Night-time in the tunnel

 

I thought my '40 changed from daytime to nighttime mode due to when it thought dawn/dusk is, but on a recent trip, it changed to night mode about 30 seconds into a tunnel, then back to daytime about 30 seconds after leaving the tunnel (long tunnel).

I don't remember it doing this before. My Nuvi 40 does not have a camera, so no 'eye'.

--
NUVI40 Kingsport TN

It

It doesn't happen in all tunnels but in lots of them. The tunnel data must be in the map data as the Nuvi has no facility that would make it change from daylight to night mode because it suddenly got dark. It only knows when the sun rises and sets.

--
Nuvi 350, 760, 1695LM, 3790LMT, 2460LMT, 3597LMTHD, DriveLuxe 50LMTHD, DriveSmart 61, Garmin Backup Camera 40 and TomTom XXL540s.

Tunnel

That Is interesting but the only tunnel near me is the one near Mount Rushmore and it is very short. I doubt it would trigger in there because you can still see daylight at the other end when you enter, so they probably would not program it to watch for that tunnel.

I could not find it in the manual but see that they added the feature with firmware version 3.8:

"Changes made from version 3.70 to 3.80:
◦Increased awareness of updating maps and software using Garmin Express.
◦Improved displayed street names.
◦Enhanced the display to switch to night color mode when in tunnels if auto color mode is selected.
◦Fixed an issue that could prevent a low battery warning message from appearing.
◦Improved the Turkish translation for 'Calculating'.
◦Improved software stability."

That's what I thought

t923347 wrote:

Nuvi has no facility that would make it change from daylight to night mode because it suddenly got dark. It only knows when the sun rises and sets.

That's what I thought.

.

t923347 wrote:

The tunnel data must be in the map data as the Nuvi has no facility that would make it change from daylight to night mode because it suddenly got dark.

t923347 is correct. The tunnel data is embedded within the map data. But this didn't used to be the case. Some Garmin models (older Street Pilots only, I believe) had an actual ambient light sensor on the unit that would dim the display when you entered a tunnel or it got dark in the car when night-time fell.

Today's models don't have a light sensor at all. They rely on the embedded map data (tunnels) and/or the time zone you're currently in (this is one purpose of the time zone map (gmaptz.img)) to know when to dim the display or change it to night-time mode.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

Thanks

This all makes sense now.

Thanks

--
NUVI40 Kingsport TN

Previous thread

Soberbyker was kind enough to post a video concerning this smile

http://www.poi-factory.com/node/42199

--
Nüvi 255WT with nüMaps Lifetime North America born on 602117815 / Nüvi 3597LMTHD born on 805972514 / I love Friday’s except when I’m on holidays ~ canuk

.

DorkusNimrod wrote:
t923347 wrote:

The tunnel data must be in the map data as the Nuvi has no facility that would make it change from daylight to night mode because it suddenly got dark.

t923347 is correct. The tunnel data is embedded within the map data. .... They rely on the embedded map data (tunnels) and/or the time zone you're currently in (this is one purpose of the time zone map (gmaptz.img)) to know when to dim the display or change it to night-time mode.

And correct he is. Taiwanese (probably other Asian models too) has built-in POIs to warn about upcoming tunnels and bridges and switch the display to night mode while in the tunnels.

I never noticed this. I need

I never noticed this. I need to check it out.

.

I use Night mode exclusively, as it's easier on the eyes.

--
nüvi 3790T | nüvi 775T | Those who make peaceful revolution impossible, will make violent revolution inevitable ~ JFK

Night Mode during the day..

In ny, Right after the toll way on 95 going to rye playland, there is a bridge/tunnel that I have to drive under, the GPS does indeed go to night when I go in it. I am wondering if I put the device in SIM driving mode, would the GPS still go from Daylight to Night Mode when it goes under the bridge/Tunnel?

Any thought? I would try it now but at work.

--
Bobkz - Garmin Nuvi 3597LMTHD/2455LMT/C530/C580- "Pain Is Fear Leaving The Body - Semper Fidelis"

Yes

Yes the GPS will go into night mode when simulating a route that goes in a tunnel that is included in the map data. I just simulated a route through the Interstate 10 Deck Park Tunnel in Phoenix, AZ and my 3597 went into night mode as it passed through it just like it does when I drive through it.

--
Nuvi 350, 760, 1695LM, 3790LMT, 2460LMT, 3597LMTHD, DriveLuxe 50LMTHD, DriveSmart 61, Garmin Backup Camera 40 and TomTom XXL540s.

Tunnels and maps

If you look at the map on the Nuvi (3597) tunnels are shown in a slightly darker shade than the normal road. unfortunately this doesn't show on the Bascamp maps.

Nice feature

Nice feature. This is the first that I had heard of it. Thanks for the info.

2595 Light Sensor

DorkusNimrod wrote:
t923347 wrote:

The tunnel data must be in the map data as the Nuvi has no facility that would make it change from daylight to night mode because it suddenly got dark.

t923347 is correct. The tunnel data is embedded within the map data. But this didn't used to be the case. Some Garmin models (older Street Pilots only, I believe) had an actual ambient light sensor on the unit that would dim the display when you entered a tunnel or it got dark in the car when night-time fell.

Today's models don't have a light sensor at all. They rely on the embedded map data (tunnels) and/or the time zone you're currently in (this is one purpose of the time zone map (gmaptz.img)) to know when to dim the display or change it to night-time mode.

Not sure when they may have dropped the light sensor or what model(s), but my 2595 does sense the ambient light level in the car and will gradually dim the display as darkness approaches. When the actual time for sunset is reached, the display switches to night mode.

I think they also changed the available light levels you can select (brightness)during some FW update in the past. I noticed recently that you can change the level to "0%". (Note: "0%" is does not mean "off".) Pretty sure the available range used to be 10-100%. I always thought 10% was still a bit too bright at times, so this was a nice discovery. I discovered it when using voice-command to change the brightness and heard it respond: "Brightness is a zero percent".

--
"Primum Non Nocere" 2595LMT Clear Channel and Navteq Traffic

.

williston wrote:

Not sure when they may have dropped the light sensor or what model(s), but my 2595 does sense the ambient light level in the car and will gradually dim the display as darkness approaches. When the actual time for sunset is reached, the display switches to night mode.

All nuvis that support gradual dimming of the display from daytime to nighttime and when entering/exiting tunnels use a combination of the map-embedded tunnel data, the current time and the time zone map. The nuvi knows when sunset/sunrise is by the current unit time along with the timezone map and will dim/brighten the display accordingly. It's quite a nifty trick. I don't believe your 2595 nor any other nuvi (past or present) has ever had a true ambient light sensor.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

Brightness driven by Time Of Day?

DorkusNimrod wrote:
williston wrote:

Not sure when they may have dropped the light sensor or what model(s), but my 2595 does sense the ambient light level in the car and will gradually dim the display as darkness approaches. When the actual time for sunset is reached, the display switches to night mode.

All nuvis that support gradual dimming of the display from daytime to nighttime and when entering/exiting tunnels use a combination of the map-embedded tunnel data, the current time and the time zone map. The nuvi knows when sunset/sunrise is by the current unit time along with the timezone map and will dim/brighten the display accordingly. It's quite a nifty trick. I don't believe your 2595 nor any other nuvi (past or present) has ever had a true ambient light sensor.

Neat! Thanks! So it adjusts by time of day and gradually clicks it down as darkness approaches? This would explain why I have noticed that even after the Nuvi changes to "Night Mode" at sunset, the display continues to dim down as it gets darker outside and in the car. This makes sense as when I think about it, the display never brightens in response to a car behind with bright lights/high beams on. I always assumed it was sensing ambient light level to make the screen brightness adjustments. I'll keep a look-out for the tunnel dimming feature....Can't say I have ever noticed it. surprised

--
"Primum Non Nocere" 2595LMT Clear Channel and Navteq Traffic

beat me to it ....

canuk wrote:

Soberbyker was kind enough to post a video concerning this smile

http://www.poi-factory.com/node/42199

I was going to point to that thread after I was done reading.

In that thread someone linked to a database of tunnels that Garmin probably gets the data from to have the GPS make the switch.

--
. 2 Garmin DriveSmart 61 LMT-S, Nuvi 2689, 2 Nuvi 2460, Zumo 550, Zumo 450, Uniden R3 radar detector with GPS built in, includes RLC info. Uconnect 430N Garmin based, built into my Jeep. .

Thanks

Thanks for the information. Now I need to make a trip that uses a tunnel! No tunnels around here to try it out on. Darn it.

Tunnel Night Mode 3490

My 3490 changes to night mode when I enter most tunnels too.

Cool Feature

I was unaware that this feature even existed. I don't recall going through a tunnel with the 3597 before yesterday and then we were passing through several north of Duluth on 61 and sure enough, as soon as it recognized I was in a tunnel per the map data, it switched to night mode until I reached the other end. This is probably one of the many enhancements that periodically comes along with the map data updates as they refine the date to included tunnel segments on a road.

--
"There's no substitute for local knowledge" nüvi 750, nüvi 3597

Tunnel

The other interesting thing about tunnel travel is that since there is no GPS signal in a tunnel, the 3597 estimates your location as you travel through.

--
Alan - Android Auto, DriveLuxe 50LMTHD, Nuvi 3597LMTHD, Oregon 550T, Nuvi 855, Nuvi 755T, Lowrance Endura Sierra, Bosch Nyon

Interesting

To bad we don't have many tunnels here, would be cool to try

Well...?

Never noticed if my Nuvi 1300WT GPS did it or not. I'll have to check it out next time I'm "tunneling". wink

Nuvi1300WTGPS

--
I'm not really lost.... just temporarily misplaced!

Good feature but...

alandb wrote:

The other interesting thing about tunnel travel is that since there is no GPS signal in a tunnel, the 3597 estimates your location as you travel through.

It's a good feature but:
- Some tunnels have pretty decent lighting
- Without GPS signal, I wonder how the unit estimates the position. Projection of the speed before entering the tunnel maybe?

Speed.

That would be my guess. It would be interesting if you were in a long tunnel to slow down or speed up and see how closely your position matches when you exit.

--
Alan - Android Auto, DriveLuxe 50LMTHD, Nuvi 3597LMTHD, Oregon 550T, Nuvi 855, Nuvi 755T, Lowrance Endura Sierra, Bosch Nyon

Position

I also believe that the speed prior to entering the tunnel is what the unit calculates as you're driving through.

I've also been stuck in bumper to bumper traffic within a tunnel and the GPS does lose satellite reception but will pick up your location when exiting.

--
Nüvi 255WT with nüMaps Lifetime North America born on 602117815 / Nüvi 3597LMTHD born on 805972514 / I love Friday’s except when I’m on holidays ~ canuk

It apparently projects position based on entry speed.

The Baltimore Harbor Tunnel is around a mile long. On rare occasions I have driven through it with my Nuvi 750W. It is common for traffic to slow considerably after entering the tunnel. The Nuvi continues to project position based on the entry speed, resulting in the Nuvi indicating you are past the tunnel when you are not. Some seconds later if you are still in the tunnel it will indicate Lost Satellite Reception.

Funny, I assumed everyone

Funny, I assumed everyone here knew about this feature. We have a few tunnels in Pittsburgh and it goes into night mode for each one and estimates the speed.

We have a number of tunnels

We have a number of tunnels here in the Pittsburgh area as well as along the PA Turnpike. The GPS estimates your travel through the tunnel based on the speed you were going when you entered and lost the signal. It can be interesting when traffic slows you down in the tunnel, or you can go faster after entering. Immediately on coming out of the tunnel the GPS acquires satellites and your position shifts from estimated to actual.