rocket timer

[Mike]

I'm currently building a mid sized camera rocket using a Kodak F-350 aps
camera, it has an electronic shutter. I will be using two switches the first
will engage very shortly after ignition and the second will make momentary
contact when the chute opens.

The first switch will begin a 1/2 second pulse which will be
triggered every 1.5 seconds for a total of 5 pulses then when the second
switch mometarilly engages the first time cycle is bypassed and a second
time cycle starts a
1/2 second pulse every 5 seconds , then after a total of 12 pulses the chip
shuts down regardless of any input. I want to do this without using a pic or
similar microcontroller because I really dont know how to program. Any
ideas?

 

[CWatters]

"Mike" <mrgizmo@vianet.ca> wrote in message
news:10e6klci94949bc@corp.supernews.com...

I'm currently building a mid sized camera rocket using a Kodak F-350 aps
camera, it has an electronic shutter. I will be using two switches the
first
will engage very shortly after ignition and the second will make momentary
contact when the chute opens.

The first switch will begin a 1/2 second pulse which will be
triggered every 1.5 seconds for a total of 5 pulses then when the second
switch mometarilly engages the first time cycle is bypassed and a second
time cycle starts a
1/2 second pulse every 5 seconds , then after a total of 12 pulses the
chip
shuts down regardless of any input. I want to do this without using a pic
or
similar microcontroller because I really dont know how to program. Any
ideas?

You could do it in hardware without using a micro but I bet you will find
you need to change the time intervals at some point. A micro is frequently
easier in the long term. See if this chap can modify the code in his rocket
timer for you.

http://www.geocities.com/ResearchTriangle/Lab/6584/r_timer.html

 

[Michael]

Mike wrote:

I'm currently building a mid sized camera rocket using a Kodak F-350 aps
camera, it has an electronic shutter. I will be using two switches the first
will engage very shortly after ignition and the second will make momentary
contact when the chute opens.

The first switch will begin a 1/2 second pulse which will be
triggered every 1.5 seconds for a total of 5 pulses then when the second
switch mometarilly engages the first time cycle is bypassed and a second
time cycle starts a
1/2 second pulse every 5 seconds , then after a total of 12 pulses the chip
shuts down regardless of any input. I want to do this without using a pic or
similar microcontroller because I really dont know how to program. Any
ideas?

I would use a microcontroller (but then I already know how to program
them). I would probably make the trigger interval programmable via
jumpers that the controller would read at power-up. Also possible to
program other things via jumper, e.g. enable/disable trigger-at-blastoff
or trigger-at-chute-open. I bet the payload weight of a micro and
jumpers would be much less than that of the same function(s) implemented
in individual logic chips. And functions implemented in a micro would
definitely be easier to modify.

 

[Mike]

I would go the pic route because it would likely be cheaper, lighter and
smaller and I do have many pics and a programmer. But I really am blond when
it comes to programming, its like learning a whole different language. I
could likely use a 12F675 since I need only two inputs and one output and it
has its own internal 1% clock and it is small, light and easy on power, but
that program stuff is greek. Also the 12F675 is a little more obscure so I
am having a hard time to find sample circuits.

"Michael" <NoSpam@att.net> wrote in message news:40E419C2.BEFEE02@att.net...

Mike wrote:

I'm currently building a mid sized camera rocket using a Kodak F-350 aps
camera, it has an electronic shutter. I will be using two switches the
first
will engage very shortly after ignition and the second will make
momentary
contact when the chute opens.

The first switch will begin a 1/2 second pulse which will be
triggered every 1.5 seconds for a total of 5 pulses then when the second
switch mometarilly engages the first time cycle is bypassed and a second
time cycle starts a
1/2 second pulse every 5 seconds , then after a total of 12 pulses the
chip
shuts down regardless of any input. I want to do this without using a
pic or
similar microcontroller because I really dont know how to program. Any
ideas?



I would use a microcontroller (but then I already know how to program
them). I would probably make the trigger interval programmable via
jumpers that the controller would read at power-up. Also possible to
program other things via jumper, e.g. enable/disable trigger-at-blastoff
or trigger-at-chute-open. I bet the payload weight of a micro and
jumpers would be much less than that of the same function(s) implemented
in individual logic chips. And functions implemented in a micro would
definitely be easier to modify.

 

[CWatters]

"Mike" <mrgizmo@vianet.ca> wrote in message
news:10e880e18tkm854@corp.supernews.com...

I would go the pic route because it would likely be cheaper, lighter
and
smaller and I do have many pics and a programmer. But I really am blond
when
it comes to programming, its like learning a whole different language. I
could likely use a 12F675 since I need only two inputs and one output and
it
has its own internal 1% clock and it is small, light and easy on power,
but
that program stuff is greek. Also the 12F675 is a little more obscure so I
am having a hard time to find sample circuits.

I'm not programmer either but I picked up PIC assembler alright. It's not
too hard if you have some examples to start from. See the page I posted
before - it has source code.