busines5

hi folks,

I'd like to build the cheapest and simplest timer possible to ignite rockets.
A timer that will count down(or up) from anywhere from 1 to 10 minutes. After count down/up is done, it should send a current to the electric match and ignite it.

Could someone with NO experience in electronics build it? Also, would it be possible to start the timer when I hook up the battery instead of pressing a button? That way I don't have to add a button; the less components I have to use the better(to keep it as easy as possible for me ).

What I think will need to be done is going to radioshack getting the components that you'll hopefully tell me to get and solder them onto a breadboard. How's my aim?

richard.c

Hi,

A 555 monostable timer as mentioned on other recent threads would work,
however with any simple electronic circuit, connecting the battery gives electrical surges that can turn on the output circuit - not something you want if you are by the rocket!

Suggests if you use this route you have the timer output isolated by a manual switch so when you connect the battery it cannot give a false firing, and a led on the output so it confirms it is not active when you switch it on.

The other simpler method would be to use an old fashioned clockwork timer or adapt one of the cheap little timers used in the kitchen or gym.

Super_voip

10 minutes seems like a long time to have a rocket sitting, primed, ready to go.

Krumlink

You could hack open a small clock and attach the ringer to the trigger of the rocket. Then you would just have to set the time to trip the alarm.

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busines5

The reason why I don't use a small clock or kitchen timer instead of making a timer myself (or i want to try anyway) is because I developed an interest in electronics. It may be temporary, I don't know, but right now I'd like to make one.

Anyways.. manual switch, good idea. Can't have false firing

Allright, so now I need to know where to go from here. Yes, I am a complete dummy when it comes to electronics. Is there perhaps a thread/webpage that has "step-by-step instructions" on how to make a simple timer? Or maybe one of you guys would be willing to give those intructions??

So i need a 555 timer and a manual switch. What else? Are there many types of 555 timers or will they know which one i need if i were to go to radioshack(??) and ask for a 555 timer?

I read about the 555 timer at wikipedia and it has 8 pins. Do i need to connect them all to something?

I'm sure making a simple timer is peanuts for some if not all of the folks here, so would it be too much to ask if i asked you to write down step by step instructions on how to make the timer? Don't worry, i won't ask you to make it too

Any help IS appreciated!

Hero999

A 555 timer isn't really suitable for delays over a couple of miniutes.

For that you could use a CD4060 or if you're also in to programming go for a microcontroller which is probably the best method.

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busines5

what about 60 seconds then?

Hero999

That shouldn't be a problem.

The circuit for a monostable 555 timer (what you want) is on the datasheet which can be found using Google.

You should be able to buy parts for the timer RadioSh@g without any problems.

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busines5

ok, i can buy the parts at radioshack.. but what parts do i need?

A 555 timer, a switch, a resistor, a capacitor, a board to put them on and jumper wires to connect them?

Hero999

Yes, that will work.

However, using jumper wires can be messy so I'd recommend you go and buy some veroboard and solder them all together.

If you look at the datasheet it gives a formula for calculatig the resistor and capacitor values.

Note that it's recommended that you add a 10nF capacitor from 0V to pin 5 and 10F in parallel with the power supply.

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busines5

ok, suppose i soldered it all together. I connected the battery and now i flip the switch in the on position(that would trigger the system, right?).. what will the 555 timer do? Count up or down and count up till what or down from what? And is there any way I can control what it will count down from?

audioguru

You don't know anything about electronics.
Why are you here? Do we look like a school for noobees??
Do knitting or gardening instead.

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Uncle $crooge

Krumlink

dude audio chill out ok? he obviously doesnt know much about electronics, but you dont need to comment like that. He is just trying to get a simple timer working ok? Chill!

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audioguru

People who don't know anything about electronics and who buy overpriced parts at RadioCrap should buy the timer product they need.
There isn't any chance that they could make a working electronic circuit.

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Krumlink

My first project I bought it from radioshack. I would get off and calm down a bit audio if I were you. Your kinda flippin out

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