This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.
Advances in electronics technology have created many opportunities for
new ideas in consumer rocketry. Electronic ignition of upper stages of
multi-staged rockets is now common. Several altimeters more recording
maximum altitude are available. Electronic deployment of recovery
devices, as well as deployment based on altitude, is now practical.
The FAQ section on High Power Rocketry has more to say about this. See
Part 2 of this FAQ for addresses of some companies selling