GPS Electronics Geek Q?

[Creamo]

I bought 2 Garmin Rino 110's , (Merry Xmas to me) and hope someone here knows a bit about electronics/timers/switches.

What they do- They can "beam" your exact location to another Rino user within a two-mile range (on the FRS spectrum) using "Position Reporting", hense buying 2. (This is a great feature. We had a blast with it in the woods over vacation.)

What they don't do- Report this location UNLESS a user, presumably another human keys the position "update position" button or keys and releases the "talk" function on the radio, each which gives an exact and current update of it's GPS position.

 In my use for it, that is not possible, it needs to be a timed event, 30 + minutes (or more) from when I turn it on. Once the second GPS unit leaves, I need it to on it's own have some sort of timed switch, wired into the talk or update button, to push, and then Release. Pushing isn't enough, as it wont updated its final position till it is actually released, otherwise I'd tape the button "open".

I can dismantle it to a certain extent, and mount it to a board no bigger than the unit itself.

Is there a simple solution I can use as a timer/actuator to do this function? Maybe some RC guys have a easy solution.

[Dux]

Make sure there are no laws against that... that could make a very handy homing/tracking device on someone who is not aware of it's existence.

[sonofagun]

Originally posted by Dux
Make sure there are no laws against that... that could make a very handy homing/tracking device on someone who is not aware of it's existence.

Hmmm...maybe the kids..or wife...or girlfriend.

Don'tcha just love technology?

[Mini D]

You should post this in the hardware forum and ask Bloom for some help.  This sounds like the type of thing that would give him a chubby.

MiniD

[sonofagun]

Shoulda checked here: (polling function)

http://www.garmin.com/products/rino130/

[Creamo]

The "Polling Function" I'm assuming is “manual”, like the 110, meaning the user would have to have to press and release the update feature. That or I’m pissed and out a lot of $.

Dux, if I did have kids I would be jailed if they are anything like my nieces, and they would surely notice the electronics board zip-tied to their zippers with a servo that went off every 30 minutes.

I could try to cross post it MiniT, but maybe he will stop in here.

[Mini D]

I don't usually see bloom in the o'club.  I'd cross post it if I were you.

MiniD

[FUNKED1]

When you key the mic it's just a switch closure.  So you bypass the switch with a Radio Shack ghetto rig circuit with a relay that closes at the proper time.

[FUNKED1]

PS what is this for?  Are you trying to give your "gimp" sex slaves a 30 minute head start during your monthly "carousel" ritual?

[bloom25]

What exactly are the steps you have to follow to send your position to the other unit?

Is it only a single button that whenever it is pressed sends your position to another radio - or is there more than one button?

If you could gain access to the wires off the bottom of the button inside the unit you could definately rig up something that would simulate pressing the button at a programmable timed interval.  I think Garmin GPSs are sealed, so obviously adding this might be a little bit tricky, as you'd want to make sure any holes you drilled for wires would have to be sealed with some silicone or something.

If this is just a single button, you need to find out how it operates.  Typically a button in a circuit with a microcontroller will pull one of the lines up to the + supply through a resistor, and pushing the button will pull the voltage on the line down to ground.  If this is how the button in your GPS works a single transistor (or in some cases just a resistor) could be used to pull the line to ground.  If it is wired differently than above, the simplest solution I can think of is a minature reed relay.  The reed relay would work no matter how the button is wired, but you'd still need a way to control the relay.

How do you get a 30 minute (for example) timed pulse to control the transistor or reed relay?  If it were mine I would just program up a little $1.68 PIC12F629 microcontroller.  In fact, if the button is wired in the manner with the pull up resistor, the total parts list would be a single 12F629 Pic, a $0.40 5V voltage regulator, and a single resistor or reed relay - definately under $10 in parts.Unfortunately this method doesn't do you a lot of good if you don't have access to a PIC programmer and can write or know someone who can write the needed software for you.  The alternative is to use something like a 555 timer chip based circuit.  This chip is very cheap ($1.50 tops), but does require 2 resistors and 2 capacitors to control timing.  You would still need the 5V voltage regulator and either a reed relay or transistor to interface with the push button.  I have seen 555 based do-it-yourself timer kits in electronics stores/magazines.  Companies like Velleman (which sell some kits through Jameco http://www.jameco.com ) make a bunch of different hobby kits and might make something that could be simply modified for the job.

[bloom25]

If you just need to push the button and can mount the unit in a rig with a push/pull solenoid next to it you might want to look at using something like this:  http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?prmenbr=91&prrfnbr=4112&cgrfnbr=501&ctgys=

You'd still need a timing circuit to activate this solenoid, something like I talked about above, unfortunately I didn't see anything ideal on Jameco's website.

If you've got plenty of room, there are time delay recycling relays out there, which could control the solenoid.  Unfortunately, they typically aren't that small.  (4x2x3 inches or so.)  They can also be pretty expensive.

[Creamo]

Thats exactly what I would need to do. It has to push the button and release. The solenoid would do the trick, but I'm thinking it will be beyond my capabilities.

As I get into it, I'll Q? you again if you don't mind. I'm kinda at a loss for now though Bloom. Thanks for the reply.