Pages: [1]   Go Down
Author Topic: How to make a timer for Rocket stage separation  (Read 1544 times)
0 Members and 1 Guest are viewing this topic.
Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi i make amateur rockets but i want to step in multiple stage rockets but i want to know if i can program an arduino UNO board as a timer to ignite the charges to separate the first stage and ignite the second motor and how can i do it since im new and i never had done an arduino robot
thanks for your time
Logged

Global Moderator
Netherlands
Offline Offline
Shannon Member
*****
Karma: 223
Posts: 13896
In theory there is no difference between theory and practice, however in practice there are many...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


what is a typical time? An Arduino can count time in steps of 4 micro seconds .

Would it be not better to let the Arduin monitor the fuel level and decide on that, iso of a clock?

Logged

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

UK
Offline Offline
Shannon Member
****
Karma: 223
Posts: 12630
-
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can't you find a way for the second stage to be ignited automatically when the first burns out, or reaches a defined point in the burn sequence? I would have thought that relying on simple elapsed time would require a lot of experimentation to find out what the normal burn duration is, and would rely on the burn duration being consistent (I have no idea whether it would actually be consistent).
Logged

I only provide help via the forum - please do not contact me for private consultancy.

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 309
Posts: 26495
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I use crushed match heads, but then, I'm pretty old-school.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Sr. Member
****
Karma: 3
Posts: 259
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I would use the ardunio to take pictures. I made a 3 stage 38 years ago made the paper Kansas city Kansan front page even first 12 year old to make a 3 stage it fired all of them. And i lost it so I would of like to had tracking.

I fired mine with the car battery    

Here this may help you http://www.apogeerockets.com/education/downloads/newsletter91.pdf
« Last Edit: December 22, 2012, 05:16:54 pm by be80be » Logged

0
Offline Offline
Faraday Member
**
Karma: 8
Posts: 2526
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Yes, an arduino can do that, although you'll need to add some transistors to switch the larger currents required for a typical e-match/igniter, and you'll need some sort of sensor (e.g. accelerometer) to detect events like launch, burnout of the previous stage, etc.

An accelerometer based system is nice because different motors have different burn times.  If you use a timer, the timer will have to be adjusted for each motor burn time.

-j
Logged

Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


what is a typical time? An Arduino can count time in steps of 4 micro seconds .

Would it be not better to let the Arduin monitor the fuel level and decide on that, iso of a clock?


they are solid fuel motors so fuel level will be hard to measure and they last between 2 seconds in stage 0 to 5 in stage 3
Logged

Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I use crushed match heads, but then, I'm pretty old-school.
i use a crushed hand lamp bulb in a little paper bag of gun powder when the current tries to turn on the bulb it ignites the gun powder
Logged

Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can't you find a way for the second stage to be ignited automatically when the first burns out, or reaches a defined point in the burn sequence? I would have thought that relying on simple elapsed time would require a lot of experimentation to find out what the normal burn duration is, and would rely on the burn duration being consistent (I have no idea whether it would actually be consistent).
i actually has tested the motors and they last almost the same in every firing with a diference of about .1 second and think i could program to when i ignite the stage 0 the timer start counting and the the motor runs out of fuel at 1.9 to 2.1 seconds at 2.5 the charges that will separate the stage fire and the upper stage is then fired this will not affect the rocket curse due the momentum it will have but i need to buil the rocket and flyit to test the hipotesis
Logged

Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Yes, an arduino can do that, although you'll need to add some transistors to switch the larger currents required for a typical e-match/igniter, and you'll need some sort of sensor (e.g. accelerometer) to detect events like launch, burnout of the previous stage, etc.

An accelerometer based system is nice because different motors have different burn times.  If you use a timer, the timer will have to be adjusted for each motor burn time.

-j

[/quote
that could be an option when the acelerometer measures a disminution in the force of the rocket apply a delay and then fire the charges that will separate the stage and ignite the upper stage and i could also use a gyro to mantain a stable fly and use small aleirons to correct the course (im also a RC plane builder) and i could achieve a less balistic flight ang get a higher apogee
Logged

Cuernavaca Mexico
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I would use the ardunio to take pictures. I made a 3 stage 38 years ago made the paper Kansas city Kansan front page even first 12 year old to make a 3 stage it fired all of them. And i lost it so I would of like to had tracking.

I fired mine with the car battery    

Here this may help you http://www.apogeerockets.com/education/downloads/newsletter91.pdf
thanks i didnt cosidered to use a dedicated timer or altimeter the thing of arduino is that you can program it to make a lot of stuff and its light but im ordering a timer from perfectflite.com to test on a smaller rocket before mounting the big one
Logged

Global Moderator
Netherlands
Offline Offline
Shannon Member
*****
Karma: 223
Posts: 13896
In theory there is no difference between theory and practice, however in practice there are many...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
Would it be not better to let the Arduin monitor the fuel level and decide on that, iso of a clock?

they are solid fuel motors so fuel level will be hard to measure and they last between 2 seconds in stage 0 to 5 in stage 3

You could add an accelerometer to detect propulsion has stopped ...
Logged

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

0
Offline Offline
Faraday Member
**
Karma: 8
Posts: 2526
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
i could also use a gyro to mantain a stable fly and use small aleirons to correct the course (im also a RC plane builder) and i could achieve a less balistic flight ang get a higher apogee

You're crossing the line between a rocket and a missile.  Most governments are pretty aggressive about maintaining their monopoly on missiles. smiley-neutral

Use simulation and modeling (e.g. openrocket or rocksim) to simulate the rocket's flight.  If you feed measurements and test flight data back into it, the simulation will be quite accurate.

Among the simulation inputs are the launch rail angle, rail length, cross wind, etc. Getting all these right will accomplish a maximum altitude about as good as you could get, even with active control, and it'll be a lot easier and safer than trying to implement active control.

-j
Logged

New Hampshire
Offline Offline
Full Member
***
Karma: 4
Posts: 179
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
Would it be not better to let the Arduin monitor the fuel level and decide on that, iso of a clock?

they are solid fuel motors so fuel level will be hard to measure and they last between 2 seconds in stage 0 to 5 in stage 3

You could add an accelerometer to detect propulsion has stopped ...


^ I like this one, itd be pretty easy to implement. Wouldn't need a full-scale arduino either since it'd be your only sensor.
Ok make it so that your uController does your ignitions. After the accelerometer maxes out during the first stage (this would be the trigger for the arduino), it waits till it goes to a lower state, then fires off the second one. No timer needed. Some If Then statements, and a bunch of spent rockets later. youll have a working system.
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 9
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

How big a rocket are you talking about?
You might want to look into http://www.nar.org/ if you are not currently involved with them
http://www.nar.org/pdf/FARrockets0209.pdf This document will tell you what is allowed by law (at least in the US).
Most multistage class 1 rockets just let the motors push the depleted stage off (talking A,B,C,D motors). The first stage uses a motor like a C6-0 that ignites the second stage by firing forward and that helps disconnect the stages.
 If you are talking about actively controlling the direction of the rocket, you are no longer talking about a class 1 rocket and have entered a whole new ball game.
Logged

Pages: [1]   Go Up
Jump to: