Project MapViewer
از طریقMicrocontroller projects.
The idea of this project was to build a device that can scroll map picture on LCD screen automatically depending of coordinates from GPS module. User can also scroll map picture manually using touchscreen. PIC32MX360F512L is used as main processor and Solomon Systech SSD1928 is an image processor that actually controls 3.5″ QVGA LCD screen. There’s also JPEG codec and SD card interface on SSD1928. Map pictures are saved to Micro SD card.
Here’s hardware I used in this project. PIC32 evaluation board and LCD module with SSD1928 chip onboard from techtoys.com.hk. There’s also a GPS module in the middle connected to PIC32’s UART1. PIC and SSD1928 are connected together through 8-bit parallel port and touchscreen is connected to PIC’s AD converter. There’s also Micro SD card socket that is wired directly to SSD1928 on the LCD module board.
I grabbed map picture from Google Maps with this handy software and then converted it from PNG to JPEG. At the moment I have made map only for my hometown Tampere with five zoom levels (11 – ۱۵ levels on Google Maps). The position on the map can be calculated like this:
x = (GPS longitude – top left longitude of the map) / longitude degree per pixel
y = (top left latitude of the map – GPS latitude) / latitude degree per pixel
Here’s the video where I’m scrolling and zooming the map. Holding the finger on the touchscreen for one second will zoom in
and double click will zoom out the map.
Certainly this device can’t replace real GPS navigator since there’s no possibility to calculate the route from point A to B. Still it could be useful and at least it’s interesting to develop stuff like this. I’m planning to add position, speed and acceleration logging features to it.
There’s drivers available in Microchip Graphics Library for SSD1926