All right, I know your out there!!!! - Northern Colorado Rocketry

This topic has 19 replies, 4 voices, and was last updated 16 years, 6 months ago by Bruce R. Schaefer.

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March 13, 2009 at 7:34 pm #40567
SCOTT EVANS
Who in this club can take this schematic, and modify it from a 555 chip,
to a 556 chip to run 2 plugs at once. I built 2 of these to run 2 guns, but would like to run both from one box.
I was told the 556 chip was the ticket!
And no it doesnt have anything to do with Rockets.
March 13, 2009 at 8:30 pm #50094
Warren B. Musselman
Moderator
That’s easy – a 556 has two 555’s inside it. Just duplicate the circuit. The 7812 is a 12V voltage regulator and the 1N4001 and 220 uF cap on the left are the power supply circuit. Everythiing else is the circuitry you need to wrap around a single half of the 556. So you just double up the parts count, check the pinout for the 556 and make adjustments for the differing pinout and you’re ready to rock. Looks like an evening with some breadboard and a little pile of parts.

Warren
March 13, 2009 at 9:12 pm #50095
mule
Participant
Oh man, Scott, what kind of trouble are you getting yourself into now???

I just got back from a trip to the home brew store, at least MY creation is going to be drinkable – at leas I hope…..
March 13, 2009 at 10:48 pm #50096
Bruce R. Schaefer
Scott, what Warren said. Simple. Just remember you have a 200 mA limit to what you can sink or source.
March 14, 2009 at 1:01 am #50097
SCOTT EVANS
Scott, what Warren said. Simple. Just remember you have a 200 mA limit to what you can sink or source.

What??? 😯 Whats sink and sorce?? 😕

You guys got to remember, it took me 3 days to get this working on a test board. With the schematic right in front of me! 😕
March 14, 2009 at 1:17 am #50098
SCOTT EVANS
Looks like an evening with some breadboard and a little pile of parts.

Warren

Yes maybe for you. 😕
To answer Gregs question: “propane powered machine guns”.
They dont fire projectiles of coarse. But they do make a loud rapid repeating report.
And yes it works when you get the gas flow, and the spark timing just right. I had one working once. Till the lady across the street threatened to call the athorities!
But the whole idea is to have two guns firing oposite of each other and maintaining sincronized fire. Will a 556 chip do that?? I guess my question is inside the 556, do the two 555s keep time with each other?
March 14, 2009 at 1:24 am #50099
Bruce R. Schaefer
They are two, independent timers on one chip. You just adjust them to any sequence you want. Forget the sinking and sourcing. If you’ve made a 555 work, then you’re fine. Do you have a 556 schematic? You can get one online. Just keep searching.
March 14, 2009 at 1:51 am #50100
mule
Participant
Looks like an evening with some breadboard and a little pile of parts.

Warren

Yes maybe for you. 😕
To answer Gregs question: “propane powered machine guns”.
They dont fire projectiles of coarse. But they do make a loud rapid repeating report.
And yes it works when you get the gas flow, and the spark timing just right. I had one working once. Till the lady across the street threatened to call the athorities!
But the whole idea is to have two guns firing oposite of each other and maintaining sincronized fire. Will a 556 chip do that?? I guess my question is inside the 556, do the two 555s keep time with each other?

You need to be in the Mad Scientists club in Denver. That’s the kind of stuff they do. Like the 200yd caulking tube cannon….
March 14, 2009 at 1:54 am #50101
SCOTT EVANS
They are two, independent timers on one chip. You just adjust them to any sequence you want. Forget the sinking and sourcing. If you’ve made a 555 work, then you’re fine. Do you have a 556 schematic? You can get one online. Just keep searching.

I have the back of the 556 package. Can you make one time the other?
I have seen schematics online.

I was looking for a way for them to keep time with each other but firing opposite of each other.
To give the sense of a more rappid fire.
March 14, 2009 at 3:18 am #50102
Warren B. Musselman
Moderator
If you want them synchronized, that’s different. You’d have to tweak the timing pots to get equivalent timing as what I was talking about was two independent circuits with a common power supply.

Why not use a single 555 with a flip-flop circuit on the output so that alternating pulses fire different output transistors?

As far as sinking or sourcing current, it’s all dependent on the output transistors and the voltage regulator capability.

Warren
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