Gps/mobile phone project.
Tibo
Posts: 81
Hi,
I used an old Garmin 92, a BS2e and a Sony Ericsson Mobile Phone to make a GPSlogger/Alarm device.
The device can read it's position, speed, course, time, ambiant light, temperature and get a ultrasonic measure, then send these informations thru mobile phone as SMS.
All the components are wired and all the code is now writen and working
.
I will use it on my boat, or as an alarm for my house, so there are two possible project configurations.
I have two questions regarding this project :
What is the smartest way to read datas from the GPS, despite the BS2e limitations (there is not enough memory to store the whole sentence so it can only read a single information at a time in a $GPRMC sentence) ?
What I wrote to do so is : for each GPS informations the program uses, I created a corresponding variable.
I wrote a SUB for each of those variables, in which the BS2e waits for the $GPRMC sentence, and then read the needed data at a precise location.
The main disadvantage of this setup is it's speed : since the program uses at least 20 variables, it runs through 20 SUBS before being able to use the datas a single time...so the sampling rate is really poor and the whole system is not reliable at high speeds (but ok for my needs actually).
I already used the PARALLAX 'state-of-the-art' technics to save RAM, I did read the regarding N&V issues, I did read the 'easyGPS' code.
I want to make sure I did not missed any clever way to do.
How to make this project electrically autonomous ?
I'd like it to be able to run on main power when avaible, and on battery if the main power is not avaible since I'd like to use it in a boat (24v) and in my place (In France : 220v 50Hz). I believe i'll need some switching device to use the main power (220v or 24v regarding to the configuration) or the battery.
In both configurations, I will also need a battery loader and a voltage dropper.
Do I miss something ? Can you help me to put a 'name' on the needed components and their specs ?
Thank you for your help.
Post Edited (Tibot) : 6/10/2006 10:08:08 AM GMT
I used an old Garmin 92, a BS2e and a Sony Ericsson Mobile Phone to make a GPSlogger/Alarm device.
The device can read it's position, speed, course, time, ambiant light, temperature and get a ultrasonic measure, then send these informations thru mobile phone as SMS.
All the components are wired and all the code is now writen and working
.I will use it on my boat, or as an alarm for my house, so there are two possible project configurations.
I have two questions regarding this project :
What is the smartest way to read datas from the GPS, despite the BS2e limitations (there is not enough memory to store the whole sentence so it can only read a single information at a time in a $GPRMC sentence) ?
What I wrote to do so is : for each GPS informations the program uses, I created a corresponding variable.
I wrote a SUB for each of those variables, in which the BS2e waits for the $GPRMC sentence, and then read the needed data at a precise location.
The main disadvantage of this setup is it's speed : since the program uses at least 20 variables, it runs through 20 SUBS before being able to use the datas a single time...so the sampling rate is really poor and the whole system is not reliable at high speeds (but ok for my needs actually).
I already used the PARALLAX 'state-of-the-art' technics to save RAM, I did read the regarding N&V issues, I did read the 'easyGPS' code.
I want to make sure I did not missed any clever way to do.
How to make this project electrically autonomous ?
I'd like it to be able to run on main power when avaible, and on battery if the main power is not avaible since I'd like to use it in a boat (24v) and in my place (In France : 220v 50Hz). I believe i'll need some switching device to use the main power (220v or 24v regarding to the configuration) or the battery.
In both configurations, I will also need a battery loader and a voltage dropper.
Do I miss something ? Can you help me to put a 'name' on the needed components and their specs ?
Thank you for your help.
Post Edited (Tibot) : 6/10/2006 10:08:08 AM GMT
Comments
I'm very interested in your project because I'm working on a similar system.
If you can show us some or all of your code, we can make some suggestions.
If you need to store many readings between downloads, some external memory may be required.
As for power supply, base it on 24 volts DC. A small switching regulator will reduce that voltage down to 5 volts or 12 volts for the electronics. At home, a mains connected power supply replaces the boat's 24 volt system.
Regards
The code is on another PC, but i'll answer your questions as detailled as I can and I'll post a full desc on th projcts forum when finished.
++
I had the same problem. The following line takes out only the variables you want, and does not save the rest. Vary it to work with the string you want:
SERIN SI,500,[noparse][[/noparse]WAIT("GPRMC,"),WAIT(",A,"),DEC4 lat_deg,DEC4 lat_sec,WAIT(","),WAIT(","),DEC5 long_deg,DEC5 long_sec] 'get lat degrees & minutes, lat decimal seconds, long degrees & minutes, long decimal seconds from NMEA GPRMC string
-Tom