Altimeter
A simple method of measuring the altitude reached by your rocket without the need of a helper. This onboard electronic device can be attached to the nose cone of your rocket and is inserted into the body tube right above the parachute or can be inserted into a payload bay if available. Electronic Altimeters incorporate a highly sensitive barometric sensor and an electronic triggering logic that provides maximum altitude at apogee.
The Estes 2246 Electronic Altimeter provides a direct LCD readout and can record heights in one foot increments up to 1000 feet (+/- 3 feet) and can store up to 10 launches in the unit's memory. The Estes Altimeter weighs about 1/2oz and is slightly over 5/8" in diameter