# 555 Timer

Discussion in 'The Projects Forum' started by Deadciv, Jan 6, 2008.

Jan 6, 2008
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Hey,
im a grade 11 student and our teacher has asked us to make a circuit with a 555 timer, a speaker, and resisters so the sound is different. What my problem is that i have no idea what to make... what i wanted to do was to make a marry go round.. but im not sure how to incorporate my motor in the circuit, if anyone could help me with the assignment it would be greatly appreciated

2. ### SgtWookie Expert

Jul 17, 2007
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Jan 6, 2008
4
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The motor is actually really fast it says its 25k RPM soo i would need some resister to slow it down. We are supposed to use a 9v battery, and i believe the motor can use around 5v - 9v. it is supposed to be made on a breadboard. and a simple outline of a piano circuit has been given to us as an outline. File is attached.

The marry go round would have only the power spinning and while the wire is spinning ti would touch each of the resistors and make a sound. All i want to know is how im going to put the motor in my circuit diagram

Thanks

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4. ### SgtWookie Expert

Jul 17, 2007
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Interesting twist!

With a motor designed to run at that high of an RPM, you're really going to need to use a ratio reduction (aka: gearbox; transmission) of some kind. Otherwise, you will have practically no torque (twisting force) and a very unpredictable speed for your merry-go-round.

A transmission could be as simple as a large rubber band stretched around the bare motor shaft to a much larger pulley on the merry-go-round. Alignment of the pulley/shaft is critical to prevent your "belt" from walking off of it.

Your motor will have nothing to do with the musical portion of the 555 circuit; it's simply there to change the resistances involved. However, you could include it parallel to the musical portion of the schematic; and have the motor connected to the "wiper arm" displayed as a dashed line (similar to a solenoid connection)

Suggestion: develop disks that can play different tunes, much as a player piano. Try such tunes as "Mary Had a Little Lamb" and "Take Me Out to The Ball Game." In order to get relatively accurate notes, resistors in parallel/series combinations are your friends.

5. ### hgmjr Moderator

Jan 28, 2005
9,030
214
You asked about how a 555 timer works. Here is a website that goes into some detail as to the inner workings of a 555 timer. There are several other sites on the web that have details on the 555. This is but one.

Here is an animation of a 555 in operation.

hgmjr

Jan 6, 2008
4
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Quick question.. is it possible to connect a parallel port with the 555 timer.. if so.. what would i need to do so? i want to see if i can control the motor to turn on .. or like the sounds to come.. or even if i add LED's.. if its possible to control them

7. ### SgtWookie Expert

Jul 17, 2007
22,182
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Here's a page on parallel port interfacing you'll find handy:
http://www.epanorama.net/circuits/parallel_output.html

[eta]
As suggested on that site, don't use the parallel port that's on your motherboard.

Get an add-on multifunction card and use that one instead. That's in case you mess things up, you don't smoke your motherboard.