Father's Day Gift (555 IC)

Hello everyone,

I am working on a electronic project for father's day. The present is a simple device that makes a magnet jump every few seconds (like a mexican jumping bean...exept it is a magnet thats jumping :lol: )

A magnet is placed in a coil and when it is connected to a 9V battery for a split second, the magnet jumps.

The problem is I now need a circuit that will turn on for about .1 seconds and then go off for about one second. This way the magnet will "jump" once a second. The ciruit should be able to repeat this cycle as long as the switch is on.

Is there a circuit based on a 555 IC that would be able to do what I want it to do ???

Please help, (Father's day is in about 36 hours :shock: )

George

George , have you got the magnet in a tube or something..?

the reason i ask , is how can you guarentee the magnet will land with the same orientation ?
if it lands upside down it may not bounce back up..

Hi,

I am not sure either how the magnet will fall back in same place without a tube or something. I'll leave that up to you.

Sorry, don't know about 555s, but you could build yourself an oscillator. Like a blinky light circuit. Using the right resistors and capacitors you can control the speed.

Try this one from Tony's site.
**broken link removed**
The transistors aren't critical.

I built that circuit a month ago and it worked very well. Theirs another LED Flasher on his site also, but I have never had any luck with that one.

So by using that circuit above you can either have two magnets jumping, or place a resitor in place of one of those LED's, to have only one magnet jumping.

Ya, Fathers day is Sunday so you better hurry. It's a simple circuit, should only take you a few minutes to build.

I insulated my Dad's shop a few weeks ago for his father's day present so I don't have anything to worry about. :lol:

D.J.

Hi George,
An ordinary 555 astable oscillator will work if the coil doesn't need more than 200mA when its loaded output voltage is reduced to about 6.5V with a brand new 9V battery. Use about a 1000uF capacitor across the supply voltage, because a 9V battery can't supply high current peaks.
One timing resistor discharges its timing capacitor for 0.1 seconds and it and the other timing resistor charge the cap for one second.
The 555 might need protection diodes if the coil has a high inductance. The protection diodes will deduce the output voltage about another volt. :lol:

A 555 is ok for the oscillator, but I use transistors instead.

I just can't see the circuit working unless the magnet part is special. In other words, if you are winding a piece of wire around a nail (with iron in it) to create an active magnet like the old days, then the only hope and prayer you will get is to treat the magnet exactly like a 2-connector dynamic (not 3 connector electret) speaker. This means you cannot connect the magnet circuit directly to the oscillator without a coupling capacitor, or you will see some devices work improperly due to a short circuit.

audioguru,

could you please provide me with a simple circuit diagram or give me a website, it would be really helpful.

thanks,

George

I agree a 555 will work for the trigger..and as mstechca also said i would use a transistor to drive the coil..
you will need more current , you could use the off time to charge the cap ..

mstechca said:

you cannot connect the electro-magnet circuit directly to the oscillator without a coupling capacitor, or you will see some devices work improperly due to a short circuit.

Click to expand...

Where is the short? :?: :?:
Why use a coupling capacitor in this DC circuit? :?: :?:
The 555 isn't an audio amplifier with its output voltage biased at half the supply. The output of a 555 is a high/low switch.
This circuit will pulse the coil very briefly. For a 555 to drive a speaker (if the 555's max current isn't exceeded) then a coupling cap is required to keep the speaker's voice coil in its center position. Then George's Mexican jumping bean would hardly twitch.

Hi George,
It is time for you to learn about 555's. The circuit and few parts selection is all in its datasheet, and all over the internet. A 555 astable oscillator circuit is very simple.

Hi Willi,
If it works OK now from an unbypassed little 9V battery, it will also work OK from a 555 circuit with the battery bypassed with a big cap, without a transistor. If George didn't measure the resistance of his coil to be sure that it won't overload the 555, then I guess he'll learn about overload the hard way. :cry:

for some reason mstechca's post was not there at the time I made my last post. :?

I have a slight change of project .... I was just fooling around with a 555 IC, a magnet, and a coil as discribed in my other post. The 555 IC is putting out a frequency of about 300 Hz and the magnet is making a buzzing sound(like a dentist drill :x ). If I get the coil's magetic field strength just right... could I suspend the magnet underneath the coil.

I could get the proper magnetic field by making the frequency higher until it floats.....NOW THAT WOULD BEAT ANY OTHER FATHERS DAY GIFT!!!

Would this work? (I hope so)

Please help

George

what type of magnet is it ? and what are the Dimensions??

Hi George,
There is a site with plans for a levitation device. It uses a Hall-effect sensor to detect how close the coil and magnet are. Then its circuit adjusts the coil's current to keep them from slamming together, like yours will do, or falling apart like yours also will do. They had their object shooting away or bouncing all over the place until they got the damping correct to match the object's inertia.
Maybe your circuit could use an LED and light-sensor to detect the distance and keep it constant. :lol:

the magnet is a neodimyum magnet (spelling is wrong, I think), it is circuitlar and about 1/3 inch in diameter. I have 6 of them, the stack is about an inch. Very powerful magnets, hard to get off one another.

tommorow, I will experiment and post my results 8)

George

They are cool arent they ..
i have a bunch of them , mine are 1/2" diam X 1/2 " long ..
and some rectangular ones ..