So could a Nextion be used for GPS?
Using a 3.5" Enhanced Nextion NX4832K035_011 (cause it has 32M flash)
It is indeed possible to load scrollable street map in to Nextion and mark location.
How much map?
indeed a bit better than 10 viewports wide and 10 viewports high.
How much area covered
certainly depends on the map resolution, but certainly something like
Which is perhaps maybe sufficient for a Metro local usage
No HMI or TFT available for this post
- TFT filesize came to 33,117,819 byes (greater than the allowed 15MB posting limit)
- Not only does loading this by microSD card make you check if you uploaded over Serial
but it takes long enough to check the upload you actually see it check % by %.
At the chosen resolution,
Nextions scrolling would indeed able to keep up with the reasonable speeds of city driving.
So a little more work on the above Nextion Navigator GPS concept
The map is flat in 1/4 second resolution (DMS) between pixels.
On a large country sized scale further away from the equator can create quiet a skew.
but for smaller areas such is not so so bad of a visual concern. But indeed some skew.
As such the above area (second map) covers
44°50'26.75" N, -63°45'41.50" (upper left)
44°29'18.50" N -63°24'33.25" (lower right)
This makes it easy to calculate location both Nextion side and from MCU side.
The Nextion is able to accept offset x.val and y.val and display lat/lon.
And because the Enhanced 3.5" Nextion was chosen, display RTC time as well.
Smooth pixel scrolling for the map is achieved and cirs provides location center.
Timer set to 139, allows for timing at almost 200ms of updates 5x per second.
- the fact cirs gets a 5/sec flicker enhances location even when not moving.
So at 1.25 seconds (DMS) per second, distance is good for 86.3mph or 139km/h
However setting x.val and y.val is more than achievable in 200ms, so any speed.
- setting this and having Nextion side calculation keeps MCU free.
Uploading 33,121,606 HMI takes 3 minutes 20 seconds via microSD
I won't be seeing how long this would be at 9600 baud folks, no way =)
Accuracy of Nextion displayed coordinates, are accurate to around 5m to 10m.
Short film of 13 seconds of map in motion,