[roc-chat] Re: ROC Launch Control System

Sweet!  Agreed on all points!

The continuity checking circuit and firmware is not difficult
I could give you all that ...

On the multi/single master concept; I guess it really depends on what
we're trying to do.

Jack sells a really nice Wireless controller which merits some investigation...
Ok, it's not mil-spec, but with a relay like some other folks have built,
it really will get you 90% of what you need...

Scaling to support 50 pads, well, that's the challenge right... I think the away
pad is the real work.. and lucky for us we don't have that many high power
birds out there...

Let's talk sometime and make some plans on this.


On 10/7/12, David Erbas-White <derbas@xxxxxxxxxxxxxxxx> wrote:

On 10/7/2012 6:03 PM, Richard Dierking wrote:

In my 'real life' job I'm working with some wireless systems (actually,

using a wireless module with our own proprietary control circuitry --

but as the module is FCC approved, don't need to worry about that end of

it).  I have tested this system on the lakebed to over a mile,

reliably.  If we were to come up with some definitions of exactly such a

'wireless dream system' were to do, I could perhaps cobble something up

that would be extensible.

Effectively, the system I'm working with is a single-master,

multiple-slave system, which would be ideal for what we're doing. To

avoid interference from other sources, we would have to use secure

encoding, along with timing, to ensure safety (i.e., a secure code to

arm the system, system disarms if it either times out or loses signal

from the master, etc.).

If we design a modular system (i.e., a relay box with batteries for

doing the actual firing, and a 'receiver section' that handles the

wireless and intelligence, we should be good to go.  Current systems (as

I envision them using these components) would require a PC to act as the

launch controller.  If we really wanted to, we could simply build a

wireless box that 'looks' like the current launch controller, but sends

the proper signals via the wireless master -- but I'm just kind of

thinking out loud...

What might be the more difficult aspect (possibly) would be the

continuity detection (wirelessly), as we would need to have the

circuitry in the range-head box to 'tell' the wireless unit if

continuity was present, etc.  And this circuitry would need to work in

conjunction with the current system of the push-button/buzzer for the

pad area itself.  We'd also need to ensure that we can handle the

wider-range of igniter firing levels (like the new Quest igniters) with

such a system..

Love to hear what other folks might think...

David Erbas-White

*Wireless System:*

These types of systems (particularly multi pad systems) are just being

developed and there's not a lot of experience using them.  If we had

to obtain a new system today, I would suggest a wireless system

because of the savings on the weight and cable cost.  But we don't

need a new system currently, so let's see what's developed over the

next couple of years and listen to their experiences.  In the

meantime, we can save for a system so when ROC's ready, we'll have the

money for a safe and reliable system.

For me, my 'dream system' would look something like this:  A small

control box would be located at each launch pad that would be the

receiver for a computer based wireless system.  The LCO would launch

rockets using a computer and daylight monitor connected to a powerful

(over 2,500' range) wireless transmitter.  The pad control box would

have a shunt and power switch controlled by the person loading the

rocket and be located on a ground stake that would also have the pad

number sign.  There would be both audible and visual arm signal on the

box and it would also have a connection for a larger battery if

necessary (i.e. more firing amps).  So, no central control boxes, just

place the launch control box with the pad number sign were you want a

pad, attach the launch leads with clips, and away you go.  This would

allow for any kind of spacing on rows.

Richard Dierking

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