Small Sized Reverse GeoCache with GPS Coordinates

The GeoCache Box is based on a PIC18F2520 microcontroller that is interfaced to GPS receiver, LCD, and lock as the box opens when it is located on predefined coordinates.

The box contains a button in order to find the coordinate. The internal GPS receiver will detect the current location when the button is pressed, while displaying the distance to the target. The box will be sealed forever if the button is pressed too often since the number of trials is limited. The internal EEPROM logs each try and the logs can be shown on the display by using a secret key combination.

A very important precondition for implementing a feature where the emergency open is done by the software is the piezo buzzer which also provides some sound feedback. This is where the box can be reset if the key combination is known. The emergency open by hardware is done by removing the 4 screws in order to slide off the lid.

The step-up converter uses a highly efficientMAX1674 along with some SMD parts to increase battery voltage to 5V. A second MOSFET is connected to the LCD and the servo.

Rest of the project