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Model Rocketry and the TI-99/4A

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There is a kid I funnel software to on an irregular basis through his father, anyway I got a call from him today passing along a question from his kid. I didn't have an answer, but said I'd pass it along. I was intrigued because I think I had once heard something similar to this back in the mid 80's, and thought it was a cool idea, but I never saw anything come of it.

 

So here are the questions (if anyone can answer them):

 

#1 Does a model rocket "countdown and launching program" exist for the TI?

#2 If not, do you think the cassette port could be utilized

with some sort of external hardware to activate the igniter

of the "Estes" type rocket motors?

#3 If yes to #2 does a schematic exist anywhere of such a device?

 

Yeah, I know this is 'out there'

 

blackpowdermotor.jpg

 

FX6NOR1F5LD8K59.MEDIUM.gif

 

Thanks.

 

 

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#2 If not, do you think the cassette port could be utilized

with some sort of external hardware to activate the igniter

of the "Estes" type rocket motors?

 

I'm don't know enough about electronics to answer that, but for those that do, perhaps this PDF that talks about the current needed for various brands of ignitors could help them answer: https://publicmissiles.com/IgnitersWhitePaperbyG-Wiz.pdf

 

My gut would probably say "no", as skimming through the document, it sounded like peak currents of anywhere between 6 and 24 amps were needed. That sounds high, but then again, I don't know enough about what the TI can output on its various ports.

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It will be very trivial to connect the parallel port to a switching transistor which in turn could activate a relay to close the circuit for the igniter. Just replace the fire button connections on the launcher wired remote control with the relay and you're done. I've used this scheme with my robot arm controller. I believe the same scheme can be applied to the cassette port.

Incidentally, I wrote a model rocket simulator for the TI in XB a while back. It's on the tigameshelf.net site under Edutainment.

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It would be trivial to activate a model rocket engine igniter through the cassette port motor control, which is simply an optoisolator. You'd have to learn enough about the TI to flip that CSR bit. There is a redneck way of doing it without understanding the underlying hardware, but I won't promote redneck hardware hacks.

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Thanks Vorticon, I'll check it out this evening when I get home. The kid loves his TI and this is his first project idea. I figure it'll be a great learning experience for him.

 

The cassette port seemed easiest if a relay type arrangement could be hooked up to the cassette cable. For him it would be easy to make, there would be no permanent modifications to the computer that way either.

 

I guess he has his heart set on the TI controlling the launch like some kind of mini Mission Control.

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I would just like to say for the record that mixing of computers as old as I am and things containing explosives is relevant to my interests. :D

 

The cassette motor control should be well suited to the task of triggering the ignition. I don't know enough TI BASIC to know how you'd do it from there or if it could be done from there. That said, if the secret sauce for controlling the optoisolator can be provided, I'd strongly encourage writing the software yourself. I've managed to get a little graphics and sound out of the TI's basic BASIC, manual in front of me, and it's exceedingly satisfying to make it do something myself, even if I was just diddling around.

 

Doing that and then making it launch a rocket? How frickin' sweet would that be?! Use the motor control to drive a transistor to handle the larger current needed by the rocket igniter. Might take putting a couple of things together to do it, but I'm sure there's folks that can tell you if you're doing it right with a quick schematic and a little info about the voltage and current that's going to be across the contacts.

 

And remember, launch video or we won't believe it happened. :D

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(somewhat off-topic -- if the content offends those I've tangled with before, I don't apologize, just click "ignore" on me and be done with it)

 

I'm still somewhat in shock that amateur rocketry is a thing in the US. When I was a kid (back when Centauri existed independent of Estes), the decent-sized engines (triple-D?) for things like the Mars lander required a license.

 

With the US as wussified and paranoid as it is, I'm surprised that amateur rocketry is even possible there now. 'Cause, you know, the flash circuit in that nosecone camera can be easily repurposed to make something go *boom* ... instant RPG.

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Doing that and then making it launch a rocket? How frickin' sweet would that be?!

 

@iKarth, I imagine it'll be kinda fun for the kid, assuming anything comes of it. Knowing his father though, I'm sure he's just looking at the educational aspects. :sad:

Regardless, the project looks fun. Now me, I always find 'alternative uses' for stuff, so I just might "re-task" his idea a little and write an XB program using my TI's CorComp clock to control something like a light... assuming of course it can be controlled from XB. I would think it would need an assembly language portion, though and I can't help the kid with that, so in the end he may be S.O.L.

 

@Vorticon, I downloaded the program after looking at the picture and reading the description, I think the kid will LOVE that program! It should help keep his imagination going, that's for sure. It'll be a couple of weeks before I'll be able to give his Dad the CF card though.

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10 !CALL LINK("ON") to turn on the cassette recorder
20 !CALL LINK("OFF") to turn it off
30 !by Ed Hall
100 CALL INIT
110 CALL LOAD(16368,79,70,70,32,32,32,36,252)
120 CALL LOAD(16376,79,78,32,32,32,32,36,244)
130 CALL LOAD(8194,37,4,63,240)
140 CALL LOAD(9460,2,12,0,45,29,0,4,91,2,12,0,45,30,0,4,91,203,78)

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(somewhat off-topic -- if the content offends those I've tangled with before, I don't apologize, just click "ignore" on me and be done with it)

 

I'm still somewhat in shock that amateur rocketry is a thing in the US. When I was a kid (back when Centauri existed independent of Estes), the decent-sized engines (triple-D?) for things like the Mars lander required a license.

 

With the US as wussified and paranoid as it is, I'm surprised that amateur rocketry is even possible there now. 'Cause, you know, the flash circuit in that nosecone camera can be easily repurposed to make something go *boom* ... instant RPG.

 

Where is home for you? You seem to have a distinct disdain for this country. If you are an American citizen and have issues with the country's direction, then by all means feel free to express your rather abrasive opinions at will with the hope however that you will also exercise your democratic power as a citizen to eventually effect positive change.

On the other hand, if you are not an American citizen, then I personally find your constant complaining about this country offensive because you really have not earned the right to knowledgeably complain about it on a public American hosted forum.

I sincerely hope it's the former.

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Mix of both. Grew up there, joined the military, left, stayed out of the US after leaving the military, no longer a US citizen due to previously mentioned concerns and the strong belief that one should be a citizen of where one has put down roots (if possible). Look around the forums and you'll pick up where I went.

 

I've earned the right to bitch about the US, and I voted with my feet. And I'm still surprised that amateur rocketry is legal.

Edited by ckoba

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By giving up your citizenship, you also gave up the credibility of your objections to the country's direction since you no longer are subject to its laws nor directly affected by them, and of course also lost the privilege of effecting change. I do hope however that the grass was greener for you on the other side.

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Relinquishing my citizenship does not invalidate my opinion about the sun rising in the east, nor my opinion about the competence of the officers I served under and with, nor my opinion of the direction your country is heading. I could be right, I could be wrong, but I do not apologize for my beliefs.

 

In my estimation, sir, your understanding of the term "credibility" needs a size-nine adjustment, as is your belief that the US will not force its laws on foreign citizens (been there, done that) nor that US policy intentionally and directly affect the policies of other governments... but you are entitled to your opinion. As I am to mine. Ain't that how America was supposed to work? Even for foreigners? Or is that right reserved only for citizens when posting on US-hosted forums now?

 

But we're very far off-topic now.

 

Now, in general: taking your "this is an American forum, hosted on an American server, and I'm offended that you don't think America is the bestest country in the world" (and that's only slightly paraphrased) ... I'll take that as my cue to leave. Good luck with your chess program.

 

I'll stay in touch via email with the AA members that I respect. I'll ask Albert to delete the "ckoba" account and all content that I posted. I don't know if he'll go along with it, but I will at least try.

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First, this is not an "American" forum in that only Americans are free to sign up and post, and in fact a very large percentage of visitors are from outside the US Second, as the American citizen who is running this website (which, yes, does reside on a server inside America's borders), I'll be the first to admit that this country has a large number of problems. But AtariAge is not the place to discuss them, as it didn't take me long to learn that discussions about politics and religion almost always degenerate into shouting, insults, and name calling. If anyone here wants to discuss such things, there are a ton of sites dedicated to these topics that will keep one busy for all eternity.

 

Ckoba, don't let one member dissuade you from continuing to participate in the forums. If you stay, please do not bait others into off-topic arguments with comments about how much you feel their country may suck.

 

Let's please keep discussion to the original topic.

Thanks,

 

..Al

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Walid.

 

If I hadn't gotten in so much trouble in the past with my big mouth I would have responded as you did. Your comments were correct and spot on. You presentation is what I wish I could do. Unfortunately my red neck streak runs deep and my emotion pump is wired straight to my mouth 😄.

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@iKarth, I imagine it'll be kinda fun for the kid, assuming anything comes of it. Knowing his father though, I'm sure he's just looking at the educational aspects. :sad:

Regardless, the project looks fun. Now me, I always find 'alternative uses' for stuff, so I just might "re-task" his idea a little and write an XB program using my TI's CorComp clock to control something like a light... assuming of course it can be controlled from XB. I would think it would need an assembly language portion, though and I can't help the kid with that, so in the end he may be S.O.L.

 

Teacher hat on, the best learning tends to happen when the kid doesn't know it's supposed to be "work". ;)

 

 

10 !CALL LINK("ON") to turn on the cassette recorder

20 !CALL LINK("OFF") to turn it off

30 !by Ed Hall

100 CALL INIT

110 CALL LOAD(16368,79,70,70,32,32,32,36,252)

120 CALL LOAD(16376,79,78,32,32,32,32,36,244)

130 CALL LOAD(8194,37,4,63,240)

140 CALL LOAD(9460,2,12,0,45,29,0,4,91,2,12,0,45,30,0,4,91,203,78)

 

Sweeeeeet.

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[..] I'll be the first to admit that this country has a large number of problems. But AtariAge is not the place to discuss them, as it didn't take me long to learn that discussions about politics and religion almost always degenerate into shouting, insults, and name calling. [..]

 

Let's please keep discussion to the original topic.

Thanks,

 

Thanks Al. It's not that I don't mind discussing and debating these things--I'm always up for a good argument, and I'd like to think I'm usually level-headed enough to acknowledge the failings of "my side" (which exist and are quite numerous especially lately.) But I think I don't really want to mix that with retrocomputing too much. Retrocomputing is what I do when and because I need to recover from the outrages and idiocies of the world around me. Code is not left or right. Code is not liberal or conservative. Vintage MPUs are easy and their agenda is only to do cool things, if you help them.

 

A person might be surprised that a lot of things are still legal, and I might tend to agree with that surprise a lot of the case, but what is, is, and what isn't, isn't. What you do about any of that is your business. But that's not here.

 

Unless y'all are working on some super-sekrit governmentproof uncrackable encryption that runs on 8 and 16 bit CPUs. with SD and CF card storage. In which case, dude, I wanna check that out! :)

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So here's a basic circuit for using the cassette port as a rocket engine igniter:

 

Rocket igniter

Here's the Extended Basic program based on Ed Hall's code:
100 CALL INIT
110 CALL LOAD(16368,79,70,70,32,32,32,36,252)
120 CALL LOAD(16376,79,78,32,32,32,32,36,244)
130 CALL LOAD(8194,37,4,63,240)
140 CALL LOAD(9460,2,12,0,45,29,0,4,91,2,12,0,45,30,0,4,91,203,78)
150 CALL CLEAR::CALL SCREEN(4)
160 DISPLAY AT(7,4)BEEP:"PRESS ANY KEY TO FIRE!"
170 CALL KEY(0,K,S)::IF S=0 THEN 170
180 CALL SCREEN(12)
190 FOR I=5 TO 0 STEP -1::DISPLAY AT(10,13)BEEP:I::FOR D=1 TO 300::NEXT D::NEXT I
200 CALL SCREEN(7)::DISPLAY AT(14,10)BEEP:"IGNITION!"::CALL LINK("ON")::FOR D=1 TO 1000::NEXT D::CALL LINK("OFF")


And here's a hasty demo of how it works. I hope it inspires a young one to experiment with the TI :)

 

https://youtu.be/4FHgEjmP8C4

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Vorticon,

I think this is EXACTLY what the kid wants! :thumbsup: I'll pass this on to him as soon as I can. Thank you so very much! :) Hopefully Radio Shack has the specific parts he needs, because without Internet access, I'm sure his dad will be calling me again about where to get the parts.

 

You know, if your circuit is scaled up for a 110V relay, people could also use the code to control items in their game rooms. Not only that, but I suppose Tim could even add the code to Mad Hatter's BBS to control a cassette player announcing audibly when the Sysop is being paged. Lot's of uses.

 

Thanks again, I'll let you know how this turns out for him.

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I hope he can make something out of it :)

A quick note: the tip of the remote plug needs to go to the positive side of the power supply, not the shaft. Otherwise it won't work.

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Vorticon,

I noticed when the TI is first turned on, or after a reset, the cassette player defaults to the on position, in the case of the kid launching rockets, or attaching an igniter, it could get a little nasty, so I added the OFF command to execute upon running the program, then I tweaked it just a tad for him, he can decide what he wants for the rest. Anyway here is the revised program listing...

 

10 CALL INIT
20 CALL LOAD(16368,79,70,70,32,32,32,36,252)
30 CALL LOAD(16376,79,78,32,32,32,32,36,244)
40 CALL LOAD(8194,37,4,63,240)
50 CALL LOAD(9460,2,12,0,45,29,0,4,91,2,12,0,45,30,0,4,91,203,78)
60 CALL LINK("OFF")
70 CALL CLEAR :: CALL SCREEN(4)
80 DISPLAY AT(7,8)BEEP:"PRESS ANY KEY" :: DISPLAY AT(9,3):"TO BEGIN LAUNCH SEQUENCE"
90 CALL KEY(0,K,S) :: IF S=0 THEN 90
100 CALL CLEAR :: DISPLAY AT(10,11):"T MINUS"
110 CALL SCREEN(12)
120 FOR I=10 TO 1 STEP-1 :: DISPLAY AT(12,13)BEEP:I :: FOR D=1 TO 300 :: NEXT D :: NEXT I
130 CALL CLEAR
140 CALL SCREEN(7) :: DISPLAY AT(10,10)BEEP:"IGNITION!" :: CALL LINK("ON") :: FOR D=1 TO 1000 :: NEXT D :: CALL LINK("OFF")
150 CALL CLEAR :: CALL SCREEN(15) :: DISPLAY AT(5,5):"RANGE SAFETY ENABLED"
160 FOR RS=1 TO 800 :: NEXT RS
170 RUN
gallery_35324_1027_8787.gif

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The example you have requires a 32K for it to work all you need is a RXB cartridge and a TI99/4A console.

 

RXB has a command named CALL IO that talks directly to the I/O chip (CRU Chip) using GPL so no Assembly is needed thus no memory expansion required.

 

100 CALL IO(2,8,11,255) ! Will turn ON Cassette Motor CRU line on for Cassette 1.

 

200 CALL IO(2,8,11,0) ! Will turn OFF Cassette Motor CRU line for Cassette 1.

 

RXB version of your program:

 

70 CALL CLEAR :: CALL SCREEN(4)
80 DISPLAY AT(7,8)BEEP:"PRESS ANY KEY" :: DISPLAY AT(9,3):"TO BEGIN LAUNCH SEQUENCE"
90 CALL KEY("",0,K,S)
100 CALL CLEAR :: DISPLAY AT(10,11):"T MINUS"
110 CALL SCREEN(12)
120 FOR I=10 TO 1 STEP-1 :: DISPLAY AT(12,13)BEEP:I :: FOR D=1 TO 300 :: NEXT D :: NEXT I
130 CALL CLEAR
140 CALL SCREEN(7) :: DISPLAY AT(10,10)BEEP:"IGNITION!" :: CALL IO(2,8,11,255) :: FOR D=1 TO 1000 :: NEXT D :: CALL IO(2,8,11,0)
150 CALL CLEAR :: CALL SCREEN(15) :: DISPLAY AT(5,5):"RANGE SAFETY ENABLED"
160 FOR RS=1 TO 800 :: NEXT RS
170 RUN
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