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Tips and questions relating to the GPS modules from SFE
#133085
I'm making one of these:
http://www.solar-balloons.com/howto.html

I could get the SSID of any nearby Wifi from a small keychain Wifi finder. It wouldn't need to be so sensitive. It could miss a few and take 5 minutes until it gets the next one from high up. Then send it via 60mw Xbee.

I would know the approximate location of the Balloon! Enough to find it anyway.

Wouldn't this be better/cheaper than GPS?
In case it was lost...
#133141
sbright33 wrote:I figured the readers of this topic would be Pro-GPS, which is the side I wanted to hear. Why GPS might be better or just as good?
Honestly, I can't think of why you wouldn't just use GPS. If cost is a big issue, you can get complete GPS units on Ebay for under $20 (eg this or this).

EDIT: I just realized those modules might be a bit heavy for your application. There are plenty of modules that are smaller & lighter (eg this, but you'd need to add an antenna). If I was making a bunch of them, I'd probably make a custom PCB with integrated chip antenna to suit a GPS module such as the Venus634LPx (you could get better prices from the manufacturer if you order a few, but it seems that particular module may not be available anymore).
#133159
You're right! $20 is cheap! I'm sold on GPS! Time is money developing my difficult method. The Venus is $80 inc ant and UART board, but it is very cool! The weight of the $20 unit shouldn't be an issue, these balloons are BIG. I will send my old USB GPS up first to prove the weight will work. Can I just plug it into the USB Host Shield? I don't need a driver to receive NMEA? I guess not, since I don't have to reply, it's 1-way communication. Software help to get me started please? Example code? I've been programming C for 20 years. It sends NMEA to my PC thru USB already.
#133168
sbright33 wrote:...I will send my old USB GPS up first to prove the weight will work. Can I just plug it into the USB Host Shield? I don't need a driver to receive NMEA? I guess not, since I don't have to reply, it's 1-way communication
Sorry, I'm not familiar with the USB Host Shield, but this seems to be an overly complicated way of doing things. A GPS unit with a TTL output would be much simpler. I guess if you already have the USB GPS unit and USB Host Shield, it might be worth a try, but certainly not if any significant coding is required.
#133172
Turns out to be quite Simple! Here's the project:
http://www.circuitsathome.com/mcu/commu ... ost-shield

The Unabridged code which should work immediately for everyone and most USB receivers:
https://github.com/felis/USB_Host_Shiel ... inygps.pde

This is the only change needed to TinyGPS:
bool feedgps()
{
uint8_t rcode;
uint8_t buf[64];
uint16_t rcvd = 64;
{
rcode = Pl.RcvData(&rcvd, buf);
if (rcode && rcode != hrNAK)
ErrorMessage<uint8_t>(PSTR("Ret"), rcode);
rcode = false;
if( rcvd ) {
for( uint16_t i=0; i < rcvd; i++ ) {
if( gps.encode(buf)) {
rcode = true;
}}}}
return( rcode );
}
#133175
Just remembered I have an old V900 logger w USB. Tiny, light and the battery lasts for a month in "Spy Mode". The only problem is that it doesn't work in 1/2 of the world. The lower half due to a bug. Unfortunately this is where I'm going...
#133330
Hooked a Razr to UNO for communication! Will test the weight requirements before I complete the project. Is it possible to use one USB Host port to talk to both GPS and phone at same time? Well you know switching one then the other.