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aucun résumé de modification
http://ladyada.net/products/ultimategps/
http://ladyada.net/products/ultimategps/
== Raccorder au PC ==
GPS modules are great in that the moment you turn them on, they'll start spitting out data, and trying to get a 'fix' (location verification). Like pretty much every GPS in existance, the Adafruit Ultimate GPS uses TTL serial output to send data so the best way to first test the GPS is to wire it directly to the computer via the TTL serial to USB converter on an Arduino. You can also use an FTDI Friend or other TTL adapter but for this demonstation we'll use a classic Arduino.
=== Le code ===
First, load a 'blank' sketch into the Arduino:
<nowiki>// this sketch will allow you to bypass the Atmega chip
// and connect the fingerprint sensor directly to the USB/Serial
// chip converter.
// Connect VIN to +5V
// Connect GND to Ground
// Connect GPS RX (data into GPS) to Digital 0
// Connect GPS TX (data out from GPS) to Digital 1
void setup() {}
void loop() {}
</nowiki>
This is will free up the converter so you can directly wire and bypass the Arduino chip. Once you've uploaded this sketch, wire the GPS as follows:
=== Le montage ===
[[Fichier:GpsUltimatedirectwire.jpg]]
=== Résultats ===
Now plug in the USB cable, and open up the serial monitor from the Arduino IDE and be sure to select 9600 baud in the drop down. You should see text like the following
[[Fichier:GpsUltimateFetch.jpg]]
This is the raw GPS "NMEA sentence" output from the module. There are a few different kinds of NMEA sentences, the most common ones people use are the $GPRMC (Global Positioning Recommended Minimum Coordinates or something like that) and the $GPGGA sentences. These two provide the time, date, latitude, longitude, altitude, estimated land speed, and fix type. Fix type indicates whether the GPS has locked onto the satellite data and received enough data to determine the location (2D fix) or location+altitude (3D fix).
For more details about NMEA sentences and what data they contain, check out this site
http://www.gpsinformation.org/dale/nmea.htm
If you look at the data in the above window, you can see that there are a lot of commas, with no data in between them. That's because this module is on my desk, indoors, and does not have a 'fix'. To get a fix, we need to put the module outside.
<font color="red">GPS modules will always send data EVEN IF THEY DO NOT HAVE A FIX! In order to get 'valid' (not-blank) data you must have the GPS module directly outside, with the square ceramic antenna pointing up with a clear sky view. In ideal conditions, the module can get a fix in under 45 seconds. however depending on your location, satellite configuration, solar flares, tall buildings nearby, RF noise, etc it may take up to half an hour (or more) to get a fix! This does not mean your GPS module is broken, the GPS module will always work as fast as it can to get a fix. </font>
== Outils ==
== Outils ==