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help needed using micromotors?

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jaspreet

New Member
hi
i m using 2 micromotors found in the mobile phone as a vibrator
which circuit i should use to drive them h bridge made by transistors or the chip ones plz do reply with some schematics and chip no.
i'll b vey thank full
 

Papabravo

Well-Known Member
Can't you just use a transistor switch to connect power to the motor. An H-bridge would only be used if you wanted to run the motor in both directions.
 

bloody-orc

New Member
if a H-bridhe then a chip. if you dont want to drive them bothways, then notmal transistors. but i hope you know that they have little power and the power cell must be wery light.
 

bloody-orc

New Member
i suggest a H-bridge chip. to find the IC name, use google and "H-Bridge IC"
 

philba

New Member
Yes, an h-bridge IC would work. Just remember that your motors will pull very little current so you dojn't need beefy drivers. You should determine the current needs of the motors. measure the current draw for unloaded and stalled (not turning). That should help you understand what your driver needs are.

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.
 
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jaspreet

New Member
ok tell me one more thing as my motor draws very little current
can i use bc548 and bc558 in h bridge if yes
then plz draw a shematic for me
 

philba

New Member
jaspreet said:
ok tell me one more thing as my motor draws very little current
can i use bc548 and bc558 in h bridge if yes
then plz draw a shematic for me

sorry, you'll have to do that yourself.

there are many resources you can use. google for h-bridge circuit. many hit.

Also, the book "Building Robot Drive Trains" by Clark & Owings is excellent and has numerous circuits.
 
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docel

Banned
philba said:
Also, the book "Building Robot Drive Trains" by Clark & Owings is excellent and has numerous circuits.

Thanks Philba !!
 

maneuver

New Member
I'm apologize for hijackin a thread here, but my question is in the same area..
These vibramotors spin at aprox. 1000 RPM, what would be the cheapest way to reduce the speed down to 80-90 RPM. I haven't tried yet, but have a suspicion that a simple resistor would drain power as well as speed. And I dont want to buy a expensive PWR, since I dont need to be able to adjust the speed once it's reduced.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
maneuver said:
I'm apologize for hijackin a thread here, but my question is in the same area..
These vibramotors spin at aprox. 1000 RPM, what would be the cheapest way to reduce the speed down to 80-90 RPM. I haven't tried yet, but have a suspicion that a simple resistor would drain power as well as speed. And I dont want to buy a expensive PWR, since I dont need to be able to adjust the speed once it's reduced.

Use a gearbox, otherwise you won't have enough power to move anything!.
 

jaspreet

New Member
hi
i think mr goodwin is saying the right thing
or the other way may be try lowering the voltage
should try some voltage regulator ic
 

Nigel Goodwin

Super Moderator
Most Helpful Member
jaspreet said:
hi
i think mr goodwin is saying the right thing
or the other way may be try lowering the voltage
should try some voltage regulator ic

Lowering the voltage will lower the speed, but it also lowers the torque, and there's not much of that to begin with!.
 

maneuver

New Member
Nigel Goodwin said:
Use a gearbox, otherwise you won't have enough power to move anything!.
That seems to be the correct thing to do... unfortunatly
What bugs me is weight, the motor is 10 grams, the batteries are 2x15 grams. The plastic walking plastic toy I'm fitting this into is roughly 50 grams. where will I find a REALLY CHEAP gearbox that dont weight more than all this together?...
 

Nigel Goodwin

Super Moderator
Most Helpful Member
maneuver said:
That seems to be the correct thing to do... unfortunatly
What bugs me is weight, the motor is 10 grams, the batteries are 2x15 grams. The plastic walking plastic toy I'm fitting this into is roughly 50 grams. where will I find a REALLY CHEAP gearbox that dont weight more than all this together?...

But will it move if you don't?.
 

philba

New Member
I agree that with out gearing down, you will basically just have a buzzer. tamiya makes a series of gear kits. I don't know if they are too big or heavy but that may be your best bet. maybe take a look at the N scale train stuff. I suspect it will be far too expensive for you.

not for the faint-of-heart but you may just have to make your own gearbox.
 

Oznog

Active Member
maneuver said:
That seems to be the correct thing to do... unfortunatly
What bugs me is weight, the motor is 10 grams, the batteries are 2x15 grams. The plastic walking plastic toy I'm fitting this into is roughly 50 grams. where will I find a REALLY CHEAP gearbox that dont weight more than all this together?...

Maybe pullies and a little string for a belt would be a good bet.

Those tiny RC cars have a motor about the same size and I think they have a gear on the output. It's still not anywhere near an 80-90 rpm outout though, you'd need more gears or a larger gear of the same tooth size.
 

philba

New Member
If you have to ask...

much too extensive subject for a post. many many ways to do this. chain drive, worm gear, ... I'm not sure where the resources are. maybe salvage toys for gears? hobby stores have gears (though I don't know what is in your corner of the world because you don't say...). get one of the tamiya gear boxes, study it. and so on... use your creativity.
 
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