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Rocketry question relating to BS2 — Parallax Forums

Rocketry question relating to BS2

ArchiverArchiver Posts: 46,084
edited 2000-03-23 00:18 in General Discussion
I'm Seth and here's my question/problem;
I am creating a rocket car which is Remotely controlled. this car will be a
standard R/C car which is made by Tamiya. The rocket engines will be mounted
on the exterior of the car using various methods (this is not an accident
waiting to happen) and will be fired using the help of a BS2, a RF
Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
The reciever will recieve a signal from the handheld unit which is with the
controller or the R/C car. then the BS2 will launch the rockets in some
fashion,and start the timer on the Pocket Watch B, and propell the car
foward, after about 1/2 a second which is about the burn time of the rockets
and light another set of them. My question is will the 5Volts that the BS2
puts out as it's output be enough to ignite the rockets.

Additional info: the rockets are lit by a simple fuse type igniter which
requires about an amp of current to pass through it to light without fail.
The igniters have a resistance of avout 180ohms. There is a 7.2 Volt battery
powering the car that can be pulled from with a simple relay.

Thanx
Seth

PS if there is need of any clarification please e-mail me

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 05:41
    Seth,

    You've read the current specs for the Stamp II right? 20ma max is the
    limit. I'd say you can't light off the fuses from the Stamp II outputs,
    you'll have to use high current transistors for that.

    DLC

    BRfan28@a... wrote:
    >
    > I'm Seth and here's my question/problem;
    > I am creating a rocket car which is Remotely controlled. this car will be a
    > standard R/C car which is made by Tamiya. The rocket engines will be mounted
    > on the exterior of the car using various methods (this is not an accident
    > waiting to happen) and will be fired using the help of a BS2, a RF
    > Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
    > The reciever will recieve a signal from the handheld unit which is with the
    > controller or the R/C car. then the BS2 will launch the rockets in some
    > fashion,and start the timer on the Pocket Watch B, and propell the car
    > foward, after about 1/2 a second which is about the burn time of the rockets
    > and light another set of them. My question is will the 5Volts that the BS2
    > puts out as it's output be enough to ignite the rockets.
    >
    > Additional info: the rockets are lit by a simple fuse type igniter which
    > requires about an amp of current to pass through it to light without fail.
    > The igniters have a resistance of avout 180ohms. There is a 7.2 Volt battery
    > powering the car that can be pulled from with a simple relay.
    >
    > Thanx
    > Seth
    >
    > PS if there is need of any clarification please e-mail me
    >
    >
    > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > http://www.egroups.com - Simplifying group communications

    --
    Dennis Clark http://www.verinet.com/~dlc
    dlc@v...
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 07:11
    At 10:41 PM 3/20/00 -0700, you wrote:

    Seth,

    If you're using a standard RC reciever connected to a Stamp to determine
    the RC signal with the PULSIN function, I would STRONGLY advise using
    some sort of software band-width checking for BOTH high and low portions
    of the receiver signal to eliminate unwanted "glitches" ... you don't
    want the rocket engaging while you flip the "on-switch" to your rocket
    car... assuming when you filp the "on-switch", you (face,hands, etc.)
    will be nearby! ;-)

    >Seth,
    >
    > You've read the current specs for the Stamp II right? 20ma max is the
    >limit. I'd say you can't light off the fuses from the Stamp II outputs,
    >you'll have to use high current transistors for that.
    >
    >DLC
    >
    >BRfan28@a... wrote:
    >>
    >> I'm Seth and here's my question/problem;
    >> I am creating a rocket car which is Remotely controlled. this car will
    be a
    >> standard R/C car which is made by Tamiya. The rocket engines will be
    mounted
    >> on the exterior of the car using various methods (this is not an accident
    >> waiting to happen) and will be fired using the help of a BS2, a RF
    >> Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
    >> The reciever will recieve a signal from the handheld unit which is with the
    >> controller or the R/C car. then the BS2 will launch the rockets in some
    >> fashion,and start the timer on the Pocket Watch B, and propell the car
    >> foward, after about 1/2 a second which is about the burn time of the
    rockets
    >> and light another set of them. My question is will the 5Volts that the BS2
    >> puts out as it's output be enough to ignite the rockets.
    >>
    >> Additional info: the rockets are lit by a simple fuse type igniter which
    >> requires about an amp of current to pass through it to light without fail.
    >> The igniters have a resistance of avout 180ohms. There is a 7.2 Volt
    battery
    >> powering the car that can be pulled from with a simple relay.
    >>
    >> Thanx
    >> Seth
    >>
    >> PS if there is need of any clarification please e-mail me
    >>
    >>
    >> eGroups.com Home: http://www.egroups.com/group/basicstamps/
    >> http://www.egroups.com - Simplifying group communications
    >
    >--
    >
    >Dennis Clark http://www.verinet.com/~dlc
    >dlc@v...
    >
    >
    >
    >eGroups.com Home: http://www.egroups.com/group/basicstamps/
    >http://www.egroups.com - Simplifying group communications
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 07:17
    Seth,

    ··· Well, i am new to this group, but i will add something.· I have not tested this, but according to OHM's Law you would need 180 volts to get 1 Amp...that is a lot...i thing that one amp is a bit too much power just for a little rocket engine...are the rocket engines the little ones used in miniature rockets...if you have the stamp send our 5 volts and the igniters have a resistance of 180ohms, then you would have a total intensity (amperage) of 27.78 mA.· I hope this helps you out a little.· These calculations are done using Ohm's Law, so they should be accurate...later amn, and good luck!!!

    -Matt/Vid
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 13:57
    The stamp won't drive it directly. I would use a fet or darlington
    transistor. I have done something similar for the pyrotechnic industry and
    use a Zetex darlington transistor to dump a charged cap to fire the ematch
    igniter. Works well. You want to be sure there is no way for this to
    ignite unless you are sure it is the time to do it for safety.


    At 11:15 PM 3/20/00 EST, you wrote:
    >I'm Seth and here's my question/problem;
    >I am creating a rocket car which is Remotely controlled. this car will be a
    >standard R/C car which is made by Tamiya. The rocket engines will be
    mounted
    >on the exterior of the car using various methods (this is not an accident
    >waiting to happen) and will be fired using the help of a BS2, a RF
    >Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
    >The reciever will recieve a signal from the handheld unit which is with the
    >controller or the R/C car. then the BS2 will launch the rockets in some
    >fashion,and start the timer on the Pocket Watch B, and propell the car
    >foward, after about 1/2 a second which is about the burn time of the rockets
    >and light another set of them. My question is will the 5Volts that the BS2
    >puts out as it's output be enough to ignite the rockets.
    >
    >Additional info: the rockets are lit by a simple fuse type igniter which
    >requires about an amp of current to pass through it to light without fail.
    >The igniters have a resistance of avout 180ohms. There is a 7.2 Volt
    battery
    >powering the car that can be pulled from with a simple relay.
    >
    >Thanx
    >Seth
    >
    >PS if there is need of any clarification please e-mail me
    >
    >
    >eGroups.com Home: http://www.egroups.com/group/basicstamps/
    >http://www.egroups.com - Simplifying group communications
    >
    >
    >
    Larry G. Nelson Sr.
    mailto:L.Nelson@i...
    http://www.ultranet.com/~nr
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 17:07
    My choice would a SCR and capacitor , the SCR ( look in Mouser.com etc ) will
    only take a few mA
    to switch completely and can dump all the charge quickly, once the charge is
    gone the SCR will be ready for another
    discharge. ( Photoflash system use SCR's for this reason)

    Date sent: Mon, 20 Mar 2000 22:41:12 -0700
    From: Dennis Clark <dlc@v...>
    Organization: TTT Enterprises
    To: basicstamps@egroups.com
    Send reply to: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Rocketry question relating to BS2

    > Seth,
    >
    > You've read the current specs for the Stamp II right? 20ma max is the
    > limit. I'd say you can't light off the fuses from the Stamp II outputs,
    > you'll have to use high current transistors for that.
    >
    > DLC
    >
    > BRfan28@a... wrote:
    > >
    > > I'm Seth and here's my question/problem;
    > > I am creating a rocket car which is Remotely controlled. this car will be a
    > > standard R/C car which is made by Tamiya. The rocket engines will be
    mounted
    > > on the exterior of the car using various methods (this is not an accident
    > > waiting to happen) and will be fired using the help of a BS2, a RF
    > > Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
    > > The reciever will recieve a signal from the handheld unit which is with the
    > > controller or the R/C car. then the BS2 will launch the rockets in some
    > > fashion,and start the timer on the Pocket Watch B, and propell the car
    > > foward, after about 1/2 a second which is about the burn time of the rockets
    > > and light another set of them. My question is will the 5Volts that the BS2
    > > puts out as it's output be enough to ignite the rockets.
    > >
    > > Additional info: the rockets are lit by a simple fuse type igniter which
    > > requires about an amp of current to pass through it to light without fail.
    > > The igniters have a resistance of avout 180ohms. There is a 7.2 Volt
    battery
    > > powering the car that can be pulled from with a simple relay.
    > >
    > > Thanx
    > > Seth
    > >
    > > PS if there is need of any clarification please e-mail me
    > >
    > >
    > > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > > http://www.egroups.com - Simplifying group communications
    >
    > --
    >
    > Dennis Clark http://www.verinet.com/~dlc
    > dlc@v...
    >
    >
    >
    > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > http://www.egroups.com - Simplifying group communications
    >
    >


    ron... the motor man...
    Ronald Doctors
    http://www.members.home.net/rdoctors
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 21:55
    I'd be very interested in seeing a schematic of how to implement the
    SCR/Capacitor combo with the BS2. It could be
    very useful for automating a flash paper canon for effects.

    Rus

    Ronald Doctors wrote:

    > My choice would a SCR and capacitor , the SCR ( look in Mouser.com etc ) will
    only take a few mA
    > to switch completely and can dump all the charge quickly, once the charge is
    gone the SCR will be ready for another
    > discharge. ( Photoflash system use SCR's for this reason)
    >
    > Date sent: Mon, 20 Mar 2000 22:41:12 -0700
    > From: Dennis Clark <dlc@v...>
    > Organization: TTT Enterprises
    > To: basicstamps@egroups.com
    > Send reply to: basicstamps@egroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: Rocketry question relating to BS2
    >
    > > Seth,
    > >
    > > You've read the current specs for the Stamp II right? 20ma max is the
    > > limit. I'd say you can't light off the fuses from the Stamp II outputs,
    > > you'll have to use high current transistors for that.
    > >
    > > DLC
    > >
    > > BRfan28@a... wrote:
    > > >
    > > > I'm Seth and here's my question/problem;
    > > > I am creating a rocket car which is Remotely controlled. this car will be
    a
    > > > standard R/C car which is made by Tamiya. The rocket engines will be
    mounted
    > > > on the exterior of the car using various methods (this is not an accident
    > > > waiting to happen) and will be fired using the help of a BS2, a RF
    > > > Reciever/Transciever (have yet to decide which one), and a Pocket watch B.
    > > > The reciever will recieve a signal from the handheld unit which is with
    the
    > > > controller or the R/C car. then the BS2 will launch the rockets in some
    > > > fashion,and start the timer on the Pocket Watch B, and propell the car
    > > > foward, after about 1/2 a second which is about the burn time of the
    rockets
    > > > and light another set of them. My question is will the 5Volts that the
    BS2
    > > > puts out as it's output be enough to ignite the rockets.
    > > >
    > > > Additional info: the rockets are lit by a simple fuse type igniter which
    > > > requires about an amp of current to pass through it to light without fail.
    > > > The igniters have a resistance of avout 180ohms. There is a 7.2 Volt
    battery
    > > > powering the car that can be pulled from with a simple relay.
    > > >
    > > > Thanx
    > > > Seth
    > > >
    > > > PS if there is need of any clarification please e-mail me
    > > >
    > > >
    > > > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > > > http://www.egroups.com - Simplifying group communications
    > >
    > > --
    > >
    > > Dennis Clark http://www.verinet.com/~dlc
    > > dlc@v...
    > >
    > >
    > >
    > > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > > http://www.egroups.com - Simplifying group communications
    > >
    > >
    >
    > ron... the motor man...
    > Ronald Doctors
    > http://www.members.home.net/rdoctors
    >
    >
    >
    > eGroups.com home: http://www.egroups.com/group/basicstamps
    > http://www.egroups.com - Simplifying group communications
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 22:43
    Seth, are you planning to dis-engage the mechanical drive system that the
    car normaly uses once the rockets ignite? I have a feeling, that once the
    rockets fire, 'IF' there is enough thrust from them to overcome added wind
    resistance and the weight of the car, your added thrust will be eaten up
    quickly by the electric motor attached to a bunch of gears. 'I could be
    wrong.'

    I like Ron's SCR idea, but maybe instead of igniting rocket engines, you
    could unload a bunch of SCRs' into the motor. I assume the motor is
    electric, since your car has a 7.2v battery.

    Another thing, check your steering, the responsiveness of it will increase
    at higher speeds.

    Chris
    (Another RC Car enthusiast)


    Original Message
    From: Ronald Doctors [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Yk8vSZvjGiY8x_wrSMBs_bcjo_KWfVCkeYVFfJ2pC5StKvLl2kO9Nb2Xnt9-Gttp2GqhIIqOtQ]rdoctors@h...[/url
    Sent: Tuesday, March 21, 2000 12:07 PM
    To: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Rocketry question relating to BS2


    My choice would a SCR and capacitor , the SCR ( look in Mouser.com etc )
    will only take a few mA
    to switch completely and can dump all the charge quickly, once the charge is
    gone the SCR will be ready for another
    discharge. ( Photoflash system use SCR's for this reason)

    Date sent: Mon, 20 Mar 2000 22:41:12 -0700
    From: Dennis Clark <dlc@v...>
    Organization: TTT Enterprises
    To: basicstamps@egroups.com
    Send reply to: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Rocketry question relating to BS2

    > Seth,
    >
    > You've read the current specs for the Stamp II right? 20ma max is the
    > limit. I'd say you can't light off the fuses from the Stamp II outputs,
    > you'll have to use high current transistors for that.
    >
    > DLC
    >
    > BRfan28@a... wrote:
    > >
    > > I'm Seth and here's my question/problem;
    > > I am creating a rocket car which is Remotely controlled. this car will
    be a
    > > standard R/C car which is made by Tamiya. The rocket engines will be
    mounted
    > > on the exterior of the car using various methods (this is not an
    accident
    > > waiting to happen) and will be fired using the help of a BS2, a RF
    > > Reciever/Transciever (have yet to decide which one), and a Pocket watch
    B.
    > > The reciever will recieve a signal from the handheld unit which is with
    the
    > > controller or the R/C car. then the BS2 will launch the rockets in some
    > > fashion,and start the timer on the Pocket Watch B, and propell the car
    > > foward, after about 1/2 a second which is about the burn time of the
    rockets
    > > and light another set of them. My question is will the 5Volts that the
    BS2
    > > puts out as it's output be enough to ignite the rockets.
    > >
    > > Additional info: the rockets are lit by a simple fuse type igniter which
    > > requires about an amp of current to pass through it to light without
    fail.
    > > The igniters have a resistance of avout 180ohms. There is a 7.2 Volt
    battery
    > > powering the car that can be pulled from with a simple relay.
    > >
    > > Thanx
    > > Seth
    > >
    > > PS if there is need of any clarification please e-mail me
    > >
    > >
    > > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > > http://www.egroups.com - Simplifying group communications
    >
    > --
    >
    > Dennis Clark http://www.verinet.com/~dlc
    > dlc@v...
    >
    >
    >
    > eGroups.com Home: http://www.egroups.com/group/basicstamps/
    > http://www.egroups.com - Simplifying group communications
    >
    >


    ron... the motor man...
    Ronald Doctors
    http://www.members.home.net/rdoctors


    eGroups.com home: http://www.egroups.com/group/basicstamps
    http://www.egroups.com - Simplifying group communications
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-21 23:35
    Well Chris in response to the mechanical drive thing i plan on having the
    wheels be modified so that if the motor is recieving a foward voltage (We
    both know there is a lot more to that but i am just talking about the end
    result) the motor will drive the wheels foward but if a backward voltage is
    put in the motor will drive but the wheels will ot spin but will just sit
    there. In the end what this accomplishes is that the car can be going faster
    than the than the motor can handle it wont be a problem, if effect it is
    cutting off the motor when the car is at the point where the motor will start
    slowing it down. And i have thought about how to stop the car, these rocket
    runs will be taking place at a dry lake bed which is about 7 miles long so
    there wont be a problem of it hitting something.

    BTW the added wind resistance is not really that much compared to the force
    of the rockets. Which for anyone wondering would be A, B, and C type engines

    About the SCR and the Capacitor. They would probably work great for small
    speed boosts and stuff like that but in reality i am just looking for a way
    to combine R/C cars and rockets because i would like to do this for a small
    rocket club i am in.
    About the Steering: i am planning on splicing the inputs and having one set
    of inputs go to the BS2 and the other to the normal reciever, also to make
    this happen easier I am controlling the voltage the reciever gets through a
    small relay which is also operated by the BS2. Also i dont know if this
    helps or not but 2 AA batteries (for a total of 3V) can ignite one of these
    igniters.

    Thanks
    Seth

    PS in response to the first response i got to the posting the reciever i am
    using for the R/C car is not going to be the same one i am using for the BS2.
    I am probably going to be using either the transciever or reciever that
    parallax sells.
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-22 04:46
    This is more a question for the other guys putting in their $.02 ,
    but should this guy be wearing a "shark suit"? - :-)

    "I am probably going to be using either the transciever or reciever
    that parallax sells."

    - I still say, use SEVERE signal discrimination when determing
    when to fire / when not to fire the rocket(s) !!! <- This is
    NOT a joke !!!

    At 06:35 PM 3/21/00 EST, you wrote:
    >Well Chris in response to the mechanical drive thing i plan on having the
    >wheels be modified so that if the motor is recieving a foward voltage (We
    >both know there is a lot more to that but i am just talking about the end
    >result) the motor will drive the wheels foward but if a backward voltage is
    >put in the motor will drive but the wheels will ot spin but will just sit
    >there. In the end what this accomplishes is that the car can be going
    faster
    >than the than the motor can handle it wont be a problem, if effect it is
    >cutting off the motor when the car is at the point where the motor will
    start
    >slowing it down. And i have thought about how to stop the car, these rocket
    >runs will be taking place at a dry lake bed which is about 7 miles long so
    >there wont be a problem of it hitting something.
    >
    >BTW the added wind resistance is not really that much compared to the force
    >of the rockets. Which for anyone wondering would be A, B, and C type engines
    >
    >About the SCR and the Capacitor. They would probably work great for small
    >speed boosts and stuff like that but in reality i am just looking for a way
    >to combine R/C cars and rockets because i would like to do this for a small
    >rocket club i am in.
    >About the Steering: i am planning on splicing the inputs and having one set
    >of inputs go to the BS2 and the other to the normal reciever, also to make
    >this happen easier I am controlling the voltage the reciever gets through a
    >small relay which is also operated by the BS2. Also i dont know if this
    >helps or not but 2 AA batteries (for a total of 3V) can ignite one of these
    >igniters.
    >
    >Thanks
    >Seth
    >
    >PS in response to the first response i got to the posting the reciever i am
    >using for the R/C car is not going to be the same one i am using for the
    BS2.
    > I am probably going to be using either the transciever or reciever that
    >parallax sells.
    >
    >
    >-- Easily schedule meetings and events using the group calendar!
    >-- http://www.egroups.com/cal?listname=basicstamps&m=1
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-23 00:18
    Could u tell me how to get "SEVERE signal discrimination".

    Thanx
    Seth
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