help needed using micromotors?

[MathGeek]

Here is the answer you are looking for

DIY gear box. Weighs very little. Reasonably cheap (less than U$D 3.00)

**broken link removed**

 

[audioguru]

How did you get the offset weight off the shaft of the vibrator motor?

 

[JimB]

where will I find a REALLY CHEAP gearbox that dont weight more than all this together?...

Have a look in the cheap clock mechanisms, the type driven by an AA size battery. There are plastic gears in those things.

JimB

 

[panic mode]

make your own, if you can sacrifice some efficiency it doesn't have to be a gearbox, you can do more or less same with a belt and pulleys (any old tape recorder or vcr will have them)

 

[AllanBertelsen]

Hi
I think you got to think small with those motors. Gearboxes and the like would be to heavy.
Look at http://www.gorobotics.net/index2.php?option=com_content&task=view&id=257&Itemid=45&pop=1&page=0
Try google words like: beam h-bridge solarbotics

 

[MathGeek]

there are several h-bridges in small packages: L239D (and not the L293 which needs external diodes) and SN 754410. Both of those will more than drive your motors. You might even be able to use 74HC series logic if the current is low enough (<30mA) but you will need diodes to prevent back emf.

Or you could build your own hbridge with transistors and diodes.

If the parts were purchased in the US, you would spend no more than a couple of dollars.

Philba,

How would you install back-EMF preventive diode for the motor?

I understand that usually, if the motor is only one directional, a flyback diode is installed across motor leads in parallel to the motor. Hence the motor and the diode forms a closed loop. Diode will be reverse biased with respect to the circuit so that no current is leaked into diode when motor is operational.

But when motor is designed to move both direction, how would this simple flyback diode design work? In one direction of current or the other, current will go through the diode instead of the motor.

Any help greatly appreciated.

 

[hjames]

How would you install back-EMF preventive diode for the motor?

Use 4 diodes in a bridge configuration to clamp the maximum motor voltage to the supply rails.

 

[bananasiong]

hey.. u have to use gearbox.. i've tried, even with very high voltage, without a gearbox, u can't move it...

 

[AllanBertelsen]

David Cook uses pager motors in this project:

https://www.robotroom.com/Appetizer.html

Google "Pager motor" and get a lot of interesting hits.

 

[maneuver]

I agree that with out gearing down, you will basically just have a buzzer.

A comment on this:
I found several identical of one toy (they hand them out at McDonalds, so they're not very sought after). So I had a couple to spare and decided to experiment. I glued the motorshaft directly onto the output shaft of the old wind-up clockwork, and removed every other flywheel from the gearbox.

The word "buzzer" comes from the sound that particular device makes. If you listen to a buzzer it says "buzzzzzzzzz". Everybody knows this.....
Bearing that in mind, what I made cannot be called a "buzzer". The correct name of my shortlived contraption would be a "click-snap-weeeeeeeeee'er"

I've actually come up with an idea about reversing the original gearbox. Turning it upside down, it will fit inside the body with only minor modifications. The weight of the removed tension spring is more than the weight of the motor, so I'm happy.

 

[jaspreet]

hi

i have to struggle with the shaft to get it off
i get it off with a nose plier

 

[maneuver]

Could you show me how you used the nosepliers to remove the weight? So far I've ripped out the entire shaft on two and cut it right of on a third motor... -So a walk-through with pictures would help.

 

[Nigel Goodwin]

I've never done it, but I've heard that crushing the weight in a vice is a good way to remove it without damaging the motor.

 

[jaspreet]

hi

it can't b shown through the pics but
hold the weight tightly and pull it out ,u have to work forcely
but take care of the motor
i will show the pic of the motor i got it from my cellphone n2300

 

[jaspreet]

here r the pics

hi
c here r the pics after getting rid of the weight
(sorry for the foggy pic it has been taken from my mobile phone)
**broken link removed**

 

[maneuver]

*giggle*
That picture was rather ..... errrr ..... pooh?

I tried the vice yesterday, that didnt work. But, then i put a Lineman's plier into the vice, and put parts of the weight into the cutting part of the pliers. And that worked like a charm. So today I'm gonna do the same with the rest of my vibramotors.

 

[jaspreet]

as i said sorry

hi
i told that before that sorry for the foddy pic of my motor
i will resend the pic this time with camcorder