Morim's rocket vault

Okey, here we go: 5..4..3..2..1...swooch... 4weeks later ...."pthssss"

That is the general idea.

So, what is spacebeer?
Well, First I have to admit that space is closer than you might expect... about 1000 m above ground. And I will not launch 25 beer bottles, instead I will launch about 30gr Hops and then brew some beer on the Hops =)

It might seem like a simple plan, but there are some big design desicions to be made.

to be contiued....

Here is a sketch of the Tasks that will be used in my Altimeter. I have struggled a bit with defining the different Tasks, but now I think that it will work. A Task should be able to run independent of other Tasks. In some cases messages will be sent between tasks (dotted lines)

I've bought a new C compiler from CCS yesterday. It is a complete IDE for C to the PIC. The Altimeter project has been in hold, waiting for this. Included is also a RTOS (Real Time Operating System), which I plan to use. Mostly because I want to try it.

CCS has a lot of HW support built in, and a good examples library, so hopefully I'll be up and running soon. The current code has to be ported from HiTech C to CCS, but that shouldn't be any problem.

Today was a sad day...
When launching G-Zezz on a G64-W there was something wrong.
After a few meters, the motor started to "chuff" and lost its power. The rocket also lost stability.
You may see (part of)the flight on the movie below. The Rocket reappears in the upper right corner, going towards ground...

G-zezz

First I suspected that the ignigter wasn't mounted correctly. If it's not fully inserted, the reload may start to burn too low, with a "chuffing" as result.

But when I inspected the motorcase, it became clear that this was not the problem.
The casing had suffered from a "Blow by" and part off the casing had melted. I wish I could blame something else, but this was probably caused by me. The forward closure was not tighten enough, which had the effect that the O-ring at the aft was not sealed, and this caused the blow by.

Well, looks like I have to order another RMS casing...

The routine for showing numbers on the display is now working.
(Tryck=preassure)
Today we have a nice high pressure over Gothenburg. I will now go to Cape Hålanda to launch G-Zezz and Big daddy...

Next step is to get the menu working.
I will add two extra switches, so there will be one for "up" one for "down" and a "enter/ok" button..

Finaly I got the 8x2 LCD working.
I had some problems first, but I solved it.
The contrast adjustment should be tied to "near ground" 0.3v - 0.0v, or else you wouldn't see anything...

The test loop simply puts an "x" to the display, clears the screen and the write an "x" again. Well, now I know that the LCD is working, and I can start doing some more serious programing. Like puting the barometric preassure in hPa and height above sea level on the screen :-)

That means some sort of clever conversion from 16bit value to a string of characters.

Now the EEPROM is working as well :-)

The gray box is a socket for reading/writing the EEPROM. I'm using PICkit 2 for programming the PIC and EEPROM.

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