Have you come out of a store and said to yourself, where did I park my car? Well, I have. Now, there are a lot of smartphone applications that can help you locate your car but smartphones are expensive.
So this Lazy Old Geek (L.O.G.) decided to make my own.
When you park your car, you press the button, car tracker calculates the car location GPS coordinates and stores them in EEPROM so the car tracker can be turned off. When you’re leaving a store looking for your car, the car tracker reads the new GPS and displays how far from your car you are and points in the direction of your car.
Step 1: Car tracker module
NOTE: This PCB was also used in MonkeyDogTracker Instructable:
It does not need an nrf24L01+ module and uses a different sketch.
The display module consists of several major components(purchased on ebay):
A Ublox NEO-6M GPS(see picture)
An LSM303DLHC magnetometer (see picture)
An LCD5110 display (see picture)
A custom Arduino PCB
A Lithium battery (see pictures)
For the battery, I selected a 3.7Vdc Lithium Ion battery also bought on ebay. This is a common type for replacement batteries for some smartphones and tablets. These come in various sizes and capacities. I had to solder a JST2.0 connector to the batteries. I hadn’t really decided on which one to use.
You can also use 18650 batteries.
I also purchased a USB Li Ion 1A battery charger and added a JST2.0 connector to charge these batteries (see picture).
Warning: The standard USB port on a computer will often only put out 0.5A. While this will work, it will take longer. The charging will be faster if a 1 or 2A source is available, such as a USB 2A AC adapter.
Arduino PCB schematic is attached. Power is regulated with a 3.3Vdc regulator. S1 is the pushbutton. U$1 is a pushbutton on/off switch:
Buz1,2 are pads for a buzzer, not used.
There is a connector labeled nrf24L01+, also not used.
There is a USB-BUB type connector for loading Arduino sketches.
The two pictures with displays shows an ‘arrow’ pointing in the direction of the collar and the distance to it.
The GPS continuously reads the latitude and longitude of the CarTracker. When the button is pressed, the coordinates are saved to the EEPROM. E.g., this would be the location of your car.
Now, let’s say you walk out of a store and are looking for your car. Power up the CarTracker. Do not push button. The GPS will read the coordinates of the store and will calculate distance and direction from there to the stored location (of the car). The compass will orient the display so the display will point to the car and will display the distance.
Step 2: Arduino Sketches
Car tracker sketch: ArduinoCarTracker.zip
Remember: In the Arduino environment, this a Pro Mini 8MHz 3.3V Board and Processor. But I’m using the ‘standard’ USB-BUB pinout so you need a USB-BUB or equivlaent (PL2303).
GPS: TinyGPS++ library
For More Detail: CarTracker – GPS Car locator