Car Finding Key Fob

Hello. I want to make a key fob that will have a ring of led's to point you in the direction your car is. I know arduino is too large for a key fob, but I want to use it to prototype designs. My problem with this project is that I dont know how to approach it. I was thinking about possibly having a little transmitter in your car that sends out where your car is to the keyfob. Do I use a gps and rf module for this? any other suggestions? thanks!

Yes, you need two GPS modules, a wireless link to send the location of the car to the fob, and a compass in the fob to interpret the relative direction between the car's GPS location and the fob's.

It will take considerable engineering to shrink all that to the size of a common fob though.

It will take considerable engineering to shrink all that to the size of a common fob though.

But something the size of a cell phone would do it, so let Google tell you about the many, many car locator apps. Or just use the backtrack option available in most handheld GPS units.

The car locator apps can only use the hardware in the phone. If the OP is interested in trying something else like radio direction-finding, then an Arduino is an appropriate prototyping platform.

This could be somewhat useful in a large carpark where GPS is not precise enough or unavailable.

there are a lot of childe finder devices

most have a distance from the tag on the child. if you get further than the set distance (10m 20m 50m) the siren in the main unit goes off. if it stays out of range the siren on the tag goes off. you can set off tag to find your kid nearby, like in a store.

I have not see one with directional capabilities.

the Android does a locator by you pressing your 'here' button to lock in a location. this would be where you left your car. the android gps knows that and can take you back to that spot.

what pauls was saying is that if you know where you are via gps and you know where your car is by gps, you can move to the car so the locations are the same.

there is such a thing we recently discussed. you put the tag on your belt and set your camera up on a tripod. as you move, the camera follows you. surfers use this to video themselves.

the technology is there so your idea is definitely possible.

I would think there might be a way to have both a broad and directional antenna. instead of LED's you might have to sweep the horizon.maybe a cover that hides the antenna so it directionalizes and you flip it open and it is broad based, or only 180 degrees ?