For many years I had an old Garmin Etrex GPS, the original yellow model. It worked on 3V (2 x AA). I could connect it to my computer and download and upload tracks, waypoints, etc.
It would connect to the serial RS232 port but it used 0V and 3V levels. The computer did not seem to mind and everything worked well.
This model had a weak and unreliable display connector and always ended failing. I had three in total and they all failed in the same way. I gave up.
Recently I was gifted (donated, presented, junked) a 2004 Magellan Explorist 300. Externally it is very similar to the old Garmin Etrex.
I have tested it and it seems to work OK except that the date is off by 1024 weeks (19.6 years, 7168 days) due to it not being prepared and understanding the 1024 week rollover. Not a major thing.
https://en.wikipedia.org/wiki/GPS_week_number_rolloverOther than that it gets the location and time of day right.
I would like to connect it to the computer like I did with the old one. It does not have an external connector but it does have a hidden port which seems very similar and I might get lucky and get it to work.
The main issue is that I need to make some kind of tiny connector, with pins that go through holes and it is difficult to make somthing and have it hold in place.
The hidden port is in the battery compartment. It has four contacts, Gnd, Txd, Rxd, Vcc. I am ssuming for now they work like the old Etrex.
The connector I make needs to have those tiny pins spring loaded.
Of the four contacts, the upper right is connected to the negative gnd and the battery big rivet on the right.
The upper left contact is directly connected to the battery + Vcc and the corresponding rivet on the left. So those two can easily be connected to the rivets/springs but the two data pins still need to make contact.
I cannot think of a really easy way to make a reliable contact for testing. The only place to hold anything is the female screw thread for the cover and it is #4-40 thread and I do not have screws with that thread. Only a standoff from a computer to confirm the thread.
I would like to do some quick and dirty testing to confirm if it can communicate with the computer. I need to handle the unit and use the front buttons so it's not like I can just place it face down on the bench and drop some pins in there.
Any ideas?