Halloween Party Project. Urgent help needed...

[sambucaman]

Hi all. Guess I'm a newbie here, but I need to ask for some help, so I hope I'm in the right place.

Right then. I am hosting a Halloween party soon, (Well, October so 3 months from now!) and I need help desgining and bulinding a project for the party.

I have a big old house, with big empty fireplaces (never used by us). I want to mount a synthetic skull up inside the chimney, about 1 foot about the hearth, and have it rigged to a timer, so every say 5 or 10 minuets it slowly lowers itself down. I would also like the skull to make a spooky noise, and maybe have flashy led eyes.

I have the skull, its been used at previous halloweens. It weighs about 3kgs, and fits nicely up the inside of the chimney with about 6" room each side.

I dont have much electronics knowledge, but I'm handy with most mechanical stuff. I'm capable of building and installing a frame of some kind to support the skull, what I really need to know is how to control the electronics of it.

Do I use mains?
What kind of motors will i need?
What will be the trigger - timer or motion sensor?
What kind of circuits will be needed?
Is there a pre-built circuit of some kind that will save some work?
MP3's for sound, or good old fashioned dictaphone? etc etc etc

Thats about it. I really do have very very little knowledge of where to start, so if any of you can help, this would be really appreciated. This is going to be an ongoing project, I'm going to follow my progress with a website so you can all see how things are going. I'll also get a mpeg of the thing in action if and when it finally works. For now though, could you all just point me in the right direction.

Thanks

 

[Dr.EM]

Ok, this sounds quite feasable. For timing periods like 5-10mins, you can use thee 555 timer chip. It is very simple to wire up as a timer, or there are kits available which will trigger a relay on the output. The relay can be used to drive your motor from a suitable power source, a battery would be easiest to work with, providing you have somewhere to put it (perhaps 4 D cells would work, but a lead acid is more suitable)

The timer kit:
**broken link removed**

Where the "stop" pushbutton is, you will want to connect this to a trip switch, so that the motor lowers the skull the correct amount, and does not continue endlessly. A reed switch and magnet should be suitable for this.

The only bit I can't think of right now is how to make it go down, and then back up to come back down 5mins later, reversing a motor can be quite compex.

The scary sound aspect could be covered with a digital recdorder IC, these are easy to trigger, and can hold a few seconds of audio, in debatable quality :lol:

 

[mstechca]

there are some motors that are so sucked out, they can't even turn a plastic bowl around.

You may need a heavy duty motor as well to be able to lift the 3kg.

 

[audioguru]

there are some motors that are so sucked out, they can't even turn a plastic bowl around.

With proper gearing, a weak motor will be able to lift just about anything (but slowly).

 

[sambucaman]

The only bit I can't think of right now is how to make it go down, and then back up to come back down 5mins later, reversing a motor can be quite compex.

Ok, the mechanism is on a crank now, so the motor only turns one way, much like a window wiper system on a car.

If I use two k2579 units, and 2 microswitchs would that work?
One switch at the lowest position which would run the timer for 5 mins, and another switch at the higest position to trigger the timer for another 5 mins.

Does that sound about right?

 

[sambucaman]

As i said in my first post i am a complete novice at electronics, but i've now got a timer, in kit form.

Now i've assembled this kit, and it all works ok - thats is to say when you press the start button the relay clicks, the led lights up, then 30 secs (or whatever its set to) the relay clicks again, and the light goes out.

My next query is, why does nothing I wire to this kit work. Am i missing something simple, or is there more to it, than just running a few wires from the kit to a bulb or motor or whatever.

It seems whatever i connect to the kit does not work, no matter what i try, or how many different wiring combinations i use.

Any more ideas guys?

The timer kit is the one linked to above in Dr Em's post

 

[Dr.EM]

The microswitches should work fine for this.

The output of that kit is via a relay, which you say you can hear clicking, which is good. The "output" of the relay is a switch, it outputs no power. To use it to operate the motor, then wire one of the relays contact terminals to the motor, the other contact to the power source for that motor and the other motor terminal to the other power souce terminal. The relay can switch a maximum of 50v, 2A, ie, a fairly small motor. If you are using an AC motor, then you'll need an AC power supply, but not the mains, as that is too many volts. To switch the mains (probably not a good idea) use a suitable relay switched by the on board one.

 

[Someone Electro]

You shod not use mains since you are inexperienced.(Or you might get yourself killed if you are not carefull whith mains)

How strong is the windows wiper motor.You can make an motor thrun backwards by simply interchanging the + and -.Some motors dosnt have the same amount of power wen thurned the oposite way.

You can controle an motor in bouth directions whith 2 proper Releys.

 

[sambucaman]

Thanks guys, Dr Em I will try that later.

Dont worry, i am steering well clear of mains for the time being!