I'm currently working on a new (barometric)altimeter.
It will sample preassuredata during the flight and store it on an 2kb EEPROM.
The data is taken from a MPX4115 preassure sensor, the value is converted by a 2chanel 12bit DAC (MCP3202) and a PIC16F690 is the "Brain". The program is written i C with HI-TECC C-compiler.
By using C I can use the logaritmic formula for calculating height (h=lg(p/P)*-7991)
This takes a lot of memory, but I'll will squeez as much as I can into the PIC.
It is still in very BETA version. The DAC is working (had some trouble setting up SPI communication) and the height calculating routines are also working.
Later I will start with the EEPROM routines and User interface and maybe connecting a 20g accelerometer to the circuit as well... :-)
And of course, build it on a circuitboard that will fit into the rockets!
Protoboard with (from left) EEPROM, DAC, MPX4115 PIC16F690