Cheap GPS (Requires some modding)

**evandude** · 08-10-2005, 02:47 PM

Originally Posted by Wiredwrx

If you would have followed the link in the first post and read the article, you would have known this.

I did follow the link and read the article before saying anything. It does not expressly say much about actually connecting it to the computer, other that "connect a serial cable", but that is slightly ambiguous. Had it been more clear about that, then stash would not have had reason to ask about it in the first place.

Again, since I did look into it more, and found that it does uses RS232 levels, I see I made a wrong assumption, and I apologize.

**stash182** · 08-10-2005, 04:31 PM

Thanks for the info. I have no understanding of this stuff.

When I said "nubbies" I meant the pins on a serial cable

How do I figure out what serial cable wires to solder to the board? the DIY looks like I only need to solder a serial input and serial output wire. Is that correct?

Originally Posted by Wiredwrx

What is a "serial port nubbie"

What do you mean by "standard serial port". The signals are the same, they are serial. Your computer "understands" serial, and the Palm Pilot "understands" serial, that is why you can connect it to the computer without additional circuitry and chips and things.

The connectors are different, Yes.

Michael

P.S. I found the thread after the PM.

**evandude** · 08-10-2005, 05:04 PM

http://www.aggsoft.com/rs232-pinout-...l-port-db9.htm

that's the pinout of the normal DB9 serial connector.

"transmit" would go to the "serial input" pin on the GPS, "receive" to "serial output", and ground to ground. don't forget the ground, you need 3 wires in all.

**stash182** · 08-11-2005, 11:24 AM

I was looking at PalmIII GPS receivers on Ebay (what few they have) and it looks like it would be even cheaper to just buy a Holux USB GPS receiver. I'll do some searching on the forum to see if this is a bad idea to use instead of the Delorme rcvr I bought at Circuit City.

**Wiredwrx** · 08-11-2005, 12:48 PM

Originally Posted by evandude

http://www.aggsoft.com/rs232-pinout-...l-port-db9.htm

that's the pinout of the normal DB9 serial connector.

"transmit" would go to the "serial input" pin on the GPS, "receive" to "serial output", and ground to ground. don't forget the ground, you need 3 wires in all.

I just re read the Mod, and it is really hard to tell what the author meant when he mentions the Pin Out. He may mean that the contact on the GPS module should GO TO Serial In and Serial Out. Or, he may mean that the GPS Module contacts are Serial In and Serial Out, and therefore, Evans direction would be correct.

If it doesn;t work the first time, then just reverse the wires and see what happens.

Michael

**evandude** · 08-11-2005, 01:35 PM

Originally Posted by Wiredwrx

If it doesn;t work the first time, then just reverse the wires and see what happens.

I agree. I've never harmed anything by hooking up transmit/receive lines backwards before. Serial ports have really, really low drive currents, so they usually don't have enough "oomph" to blow anything up if you hook the transmit lines together.

**kiltjim** · 08-11-2005, 04:55 PM

Wow. I never imagined I'd see that again. I have the exact unit tucked into an Altoids can under my dash. I followed the directions he has on his site, and everything has been working since. If I get ambitious, I'll find the notes I made when putting it together. Works very well by the way.

**stash182** · 08-11-2005, 07:11 PM

how much did it cost you to make this? I dont see why someone wouldnt just go with a receiver off Ebay that requires no mods for $30. It's near impossible to find a Palm III receiver.

**Wiredwrx** · 08-11-2005, 07:58 PM

Originally Posted by stash182

how much did it cost you to make this? I dont see why someone wouldnt just go with a receiver off Ebay that requires no mods for $30. It's near impossible to find a Palm III receiver.

Where did you see a receiver for 30 bucks?

Michael

**kiltjim** · 08-11-2005, 11:11 PM

Well, a year or two ago I found it for about $30. A year ago, even the Palm III reciever was unpopular. You may not be able to find it now.

If you want, I'll sell you mine with the extremely custom serial/PS2 cable for like $150. Its very rare. It has like a 20' cable with a DB9 connector on on end, and a DB9 and PS2 connector on the other end. The PS2 connector is for power. Works flawlessy. I'll even include a handwritten note verifying its authenticity.

Any takers?