Rocket Altimeter

[murphy6]

Hello Everyone,
I am looking for instructions, schematics, and PICBASIC programming code for a rocket altimeter. My friends and I are new to using PICs and PicBasic so we need a detailed schematic and PicBasic program. I have noticed that there are some postings for altimeters, but we are using the 16F84(a). If someone could help us with any of these things it would be much appreciated. We have been working through some simple projects to get familiar with PICBASIC. Please, we only have PICBASIC not PICBASIC PRO.

PS we are thinking of using a pressure sensor because its easier???

Thank You
murphy6

[G-R-C]

Hey Murph
I don't have alot info on altimatures, however these are real popular
with the high power model rockets. Maybe a model rocket site will have some
links on how to build your own. In fact I saw one my friend had.
On his altimature there was a 16F874 pic. Also you might want to
consider using a 16F628 pic instead of the 16f84 (more program memory,
more features and cheaper).

Sounds like a real cool project. Hope you find an answer.

Gordon

[G-R-C]

Hey again Murph.
Here is link that might point you into the right direction.
Looks like this guys made a couple versions on an altimeter.
One of them was a pic based version.

http://www.geocities.com/jpadfield13/altimeter.html

Hope this helps.

[G-R-C]

one last note. The code in the link is in PicBasic Pro,
however the .HEX file is there and you should be able
to load that into the PIC. Or you write your own code.

[Acetronics2]

Hi, Murphy

You should have a look to :

http://geocities.com/SiliconValley/O...er.html?200716

it's PbP compatible ...

and explanations given ...

Alain

PS: Murphy's Law : What goes up must go down ... more or less kwickly.

[srob]

I built one a couple of years ago to fit Estes BT-50 (or similar) body tubes. I used a freescale MPX2100 pressure sensor

http://www.freescale.com/files/senso...00.pdf?pspll=1

The problem you may face is the output is analogue and the 16f84 has no ADC. I would recomend a different PIC, which as a 10-bit (how accurate do you want it?) ADC and also internal osc. Because of small size and weight, you will want to keep the number of components to a minimum.

Also the relationship between pressure and altitude is non-linear (and also depends upon temperature, but the MPX2100 compensates) so I used a look-up table to convert from pressure to height. Another consideration is the output, mine had a serial output (which requires laptop and hyperterminal!) which I replaced with a LED that flashed the maximum height, I have also seen a buzzer used inplace of the LED.

If you want to log the flight in stead of apogee - use a really fast PIC!

For more info try asking your local rocketry club - for me in the UK, I would start with UKRA.

www.ukra.org.uk.

Hope this is helpful

[BobK]

Hello,

You can also look at the devices made by www.transolve.com. John had an article published in the old Radio-Electronics magazine back in the early 90's using an RCA 1802 micro for an altimeter. It had a plugin display so you could see the rocket's progress in flight. He only uses PICs now. He works closely with several high powered rocket clubs now and has ads in the major rocketry magazines. Check him out.

BobK