This blog covers the day to day progress of water rocket development by the Air Command Water Rockets team. It is also a facility for people to provide feedback and ask questions.

Wednesday, June 11, 2008

Weekend Work

We worked on a number of different projects this weekend. We started a small production run of nosecones with integrated deployment systems using the new V1.5 flight computer. The idea is to build a number of these nosecones into our inventory so that we can simply screw in a new one should one become damaged. This will allow us to continue development on new projects without the need to spend a lot of time on repairs.


We also fixed up the launch release mechanism on the medium launcher after a hairline crack developed in the riser air tube. We have replaced it with a shorter much sturdier pipe that can be unscrewed. We also built a couple of swappable release heads with integrated launch tubes. The release head fitted to the release mechanism (image below) is a standard 9mm nozzle. The other two release heads are 15mm nozzles one with a 26cm launch tube to go into single bottle or robinson coupled rockets and the other has a 112cm launch tube to be used with longer, Tornado coupled and FTC rockets.


We've also did some more work on the new staging mechanism, but mostly just epoxying parts together.

We've fitted the endcap and nozzle on a full length of FTC now as we really want to get this first FTC rocket test flown. It will be launched with the new long launch tube shown above. There is still quite a bit of work to do especially on the recovery system.
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16 comments:

Anonymous said...

hi, i'm da-water.
i'm still building my flight computer...
i was wondering about how the g-switch works...
what is it? is it a normal switch?a jumper?did you modify any part of the g-switch, or you bought it without modify anything?
congratulations for v1.5.... it's great!

D.D. ROCKETS

p.s.: i had to write as anonymous because i have problems leaving comments on blogger...

George Katz said...

Hi da-water,

Good to hear about your progress with the flight comp. There are two types of G-switches we use. One is a commercial product from RS electronics. Goto:

http://australia.rs-online.com

and search for "acceleration switch" they have a number of them depending on the G's you need to detect. But they are a little pricey.

The other G-switch we use is simply made from a small extension spring soldered to the PCB with a weight on the end of it. See photos of V1.3.2 of our flight computer for details.

An extension spring works better than a compression spring as it is less sensitive to vibration.

Anonymous said...

(da-water said)

ok,thanks for informations, bye,bye

Jérémy Lorion said...

Hi, i'm Jérémy
I have done your flight computer but i have a little problem with it. I Turn the computer on but nothing is happening, the seven segment led does not work.On your schedule the numbers of the pins are not the same as in real on the real display .can you give me the real numbers of the pins on the 7 segment led
thank you for help me

George Katz said...

Hi Jeremy,

What is the component number of the 7 segment LED display? Is it a common cathode display? If you tell me what the LED display is that you are using I'll let you know which pins to connect up.

Jérémy Lorion said...

Hi it's Jeremy

i found the problem
one, three leds of the display did not work anymore
and the pic send + signals to the display but my display can only recevie - signals
i will just change the display and then i think it will work
.I tested my first rocket 7.5 L but there was a leak, i will fix it tommorow

Anyway thank you for helping me Great work

Ps:i am french so my english is not perfect

George Katz said...

Good to hear that you found it. :) Must have been a common Anode LED display.

Jeremy Lorion said...

Hi Jeremy
i finished the computer but a have a problem ,it doesn't work .i don't know what is wrong .on my microcontroller ii can read PIC16F628A i/p. But what's i/p ?.i checked everything
:(
Bye

George Katz said...

Hi Jeremy,

When you downloaded the HEX file to the PIC chip, did you do a verify to make sure the chip was programmed properly?

Does the display show anything?

If you can send me a picture of the board (bottom and top) I might be able to help out.

Jeremy Lorion said...

Ahh i forget to program the chip
:P
everything is all right
just a question how do you program it .
it's the first time for me.

Jeremy Lorion said...

i forget to ask something where can i get the hex file . i can't find it on your site for the 1.5 FC

George Katz said...

Just send an email to katz.george AT gmail.com and I will email you the HEX file. You will need to either get or borrow a PIC programmer to put the HEX file on the chip. You could also ask a friend to do it for you.

Jeremy Lorion said...

i didn't understand that i must send an email to you because for the other FC i can download it .someone said me that you can use a serial port and then put some pins of the microcontroller in the serial port .is it possible
? .i have to download a program but i don't know wich.
thanks

Jeremy Lorion said...

is it possible?

George Katz said...

Hi Jeremy, you need a PIC programmer to program the chip. You cannot connect RS232 to it directly to program it. I sent you an email with the HEX file attached that must be downloaded to the chip.

Jeremy Lorion said...

yes,i looked yesterdey at it
i think i will buy one
thanks a lot