Is There Such

Thread Starter

george0039

Joined Oct 15, 2008
167
Hello

I have a audio circuit that has an audio file in it of a helicopter main motor starting up. I would like to know is there a circuit that is a motor driver that can be sync up to the audio board? That way as the sound of the main helicopter motor start, then so does the little brushed motor. As the sound intensifies, like the motor is speeding up then so would the brushed motor.

Is that possible OR is there a Single board that I could download a sound effect file into and it would also control a small brushed motor?

Any links to one would be great!

Thanks

George
 

Ramussons

Joined May 3, 2013
1,404
One way would be to have a voltage controlled voltage regulator feeding your motor. The control voltage will be derived by rectifying the output of your sound.

Louder sound => higher voltage to the motor.

Ramesh
 

Thread Starter

george0039

Joined Oct 15, 2008
167
One way would be to have a voltage controlled voltage regulator feeding your motor. The control voltage will be derived by rectifying the output of your sound.

Louder sound => higher voltage to the motor.

Ramesh

Hi

Would that have any effect on the audio playback, in terms of lowering the audio volume? Is it possible for you to show me a circuit that could do that?

Thanks

George
 

wayneh

Joined Sep 9, 2010
17,496
You need to define the behavior of the motor. Would a slow ramp up in rpm work? The sound file is like a clock, and you can determine for each time interval what rpm you want. Once you know that rpm-vs-time profile, someone here can probably come up with a clever way to implement it.
 

Thread Starter

george0039

Joined Oct 15, 2008
167
Hi

Yes the sound ramps up. Just like the areal helicopter motor in the shut down position you hear it winding up towards full speed.

I would like the dc motor to do the same BUT my space for the electronic board is not great, I need to know the size of the circuit board for this to see if it will fit.

George
 

wayneh

Joined Sep 9, 2010
17,496
Yes the sound ramps up. Just like the areal helicopter motor in the shut down position you hear it winding up towards full speed.

I would like the dc motor to do the same
I think the easiest way does not require any "synch" with the audio. If you know the audio ramps up in, say, 5 seconds, and it's always the same, then you just need to ramp up the rpm over 5 seconds. You could use PWM to control the motor speed, and then you need a way to ramp up the duty cycle of the PWM from 0 to 100% over 5 seconds.

I'm not fluent in this area but I've seen voltage-controlled PWM circuits here lately, and I know a simple op-amp circuit can give you a linear voltage ramp. That's probably where I'd start, until somebody comes by with a more elegant solution.
 

Thread Starter

george0039

Joined Oct 15, 2008
167
Hello Again

Well I want to Thank all for your help so far. Since I am new to this I still need to look at circuits to know what you mean and if I can even attempt to put one together on a DIY solder experimentor`s board.

Any Help with the design circuit would be Great!

Thanks

George
 

wayneh

Joined Sep 9, 2010
17,496
Start with building yourself a PWM motor controller using the 555 timer IC, since you'll need this no matter what other solution you choose. There's plenty of info on this at this site. Look for Bill's MOSFET drivers. I can never remember where to find it, but it's here somewhere. ;)

[here is what I was thinking of]
 
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Thread Starter

george0039

Joined Oct 15, 2008
167
Hello Bernard

Thank you for the circuit help.

Since I am still new to this I will ask SgtWookie if he sees this to describe his circuit since I don`t see the pin. numbers for either I.C or are they the same one? The Circuit is the one posted by Bernard above.

Also my audio circuit is from electronics123.com, it has been programmed with the sound file so I need to know how to connect it to this circuit so that I still have sound as well as powering the small DC motor, 3-5v 1A max.

I hope the included information is enough for you to help me better understand what I have to do to get both circuits to work together.

Thanks

George
 

Thread Starter

george0039

Joined Oct 15, 2008
167
Hello Again

I sent SgtWookie an email to bring this post to his attention and my need of his help.

The rest of this post will be in public.

George
 

SgtWookie

Joined Jul 17, 2007
22,230
I have been travelling out East (MI and upstate NY) for over a week; today is the National Museum of the USAF in Dayton OH. I won't get home until late tonight, and will have a great many things to do when I get home.

No, that circuit won't work for you as-is. No, I don't have time to work on it.
 

Bernard

Joined Aug 7, 2008
5,784
George, did you look up data sheet on LM2903? LM393 same function & pinout. U1a-1 = out; U1a-2 = - in; U1a-3 = + in; U1b-6 = - in; -5 = + in, -7 = out; VCC= 8; Gnd = 4. Connect DC ramp to ref, U1b-5; pot[ 10k or 100k]. is used for testing & not part of circuit. Make R3 a 100k +- pot for testing, then replace with fixed R, same with VR1, stay on low side, say 2 kHz. More later.
 

wayneh

Joined Sep 9, 2010
17,496
It's worth noting that this circuit is similar to the one in Bill's Fig 10.4 that I linked above. It uses less parts because it uses the comparator as the oscillator instead of a 555, but the idea is the same: Feed a sawtooth waveform to a comparator, and adjust the reference voltage on the other pin to change the duty cycle of the output.

By controlling the reference voltage, you control the duty cycle and thereby the speed of the motor. From there you just need a way to ramp the reference voltage, and that's pretty easy.

You might want to use a quad op-amp. Two of the amps could serve the role of the two comparators in Sarge's circuit. A third one could provide the slow ramp, see here for an example.
 
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