Eggtimer Rocketry
Eggtimer Model Rocket Flight Computer  
The Eggtimer Model Rocket Flight Computer is a full-function barometric two-channel flight computer that can be used to deploy parachutes, airstart second-stage engines, and log flight profile data.    It supports standard main-drogue  multiple chute deployment, or you can use your motor's ejection charge to deploy the drogue chute and configure the drogue channel in airstart mode to support a two-stage multiple deployment rocket.  It can be used to modulate  standard hobby servos too, so if you're a water rocket enthusiast this is the only solution on the market that can be used for non-pyro multiple deployment.

It is sold as a kit to keep your cost down, at $35 for the complete kit it is by far the least expensive full-function flight computer on the market.  We designed it to be easy to put together, the few SMT parts are pre-mounted on the circuit board for you so you don't need to worry about them.  All you have to do is to solder about 30 standard through-hole parts, and either "pigtail" wires to the termination of your choice, or you can use the optional locking header/socket kit to make your Eggtimer easily swappable between rockets.

Barometric pressure sensor, accurate to over 30,000 ft.

Non-volatile EEPROM for flight history storage, holds your last 32 flights

Two configurable high-current output channels, each good for over 8A / 60V (65W maximum), plus three separate logic-level outputs (drogue, main, and landing)

Output channels' "on-time" can be configured from 1 second to 9 seconds, and can also be set to stay on continuously

Support for airstarts with three separate events required for safety (breakwire trip, launch detect altitude, motor burn/airstart delay timer expiration)

Can be used to modulate standard hobby servos as well as firing pyro igniters, each channel can be programmed separately so you can mix them if you wish

Fully programmable flight parameters AND eight pre-programmed flight profiles, so you can use it in the field without a computer.  Sample rate programmable from 4-33 samples/sec, separate settings for each major flight phase (burn/coast, and descent)

Small size – About 3.9" long and 1" wide.  Can easily fit in a 29mm motor mount or BT-55 size rocket.  
Weight < 20g.  

Filtered altitude/velocity sampling to eliminate false triggering of ejection charges due to mach transition
Current draw approx. 8 mA, 2mA in standby mode
Separate battery connectors for computer and igniter outputs to prevent "brownouts", each output channel can have a separate battery (great for redundancy, or if you want to mix pyro and servos)
High-current output channels are electrically isolated from the processor with opto-isolators, igniter  firing cannot cause a "brownout" that resets the flight computer (and ruins your whole day!)
Batteries, breakwire, and deployment continuity tested before flight, alerts you if something is wrong
Remote reset terminals to put computer on-hold while on the pad, without drawing full power

Provision for remote Ready indicator LED,  buzzer, and deployment channel continuity LEDs so you can check your Eggtimer's status without having to open up the payload bay
Beeps out peak altitude after flight
PC/Mac communication using USB-TTL Serial 3-pin cable (included) and any standard VT100 terminal emulator program (many available for free on the Internet)
Real-time TTL serial output of elapsed flight time and altitude can be interfaced to an RF transmitter module for ground-based flight recording (not included, obviously!)

Downloads both text parameters/summary report and CSV-formatted detail flight data (elapsed time, raw altitude, raw velocity, filtered altitude, filtered velocity) for use with standard graphing programs (Excel, Plot)

Firmware can be updated using the included USB-TTL Serial cable, no charge for firmware updates

Optional locking header-socket kit so you can easily move it from one rocket to another (RevD board only)