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Help with a simple circuit please

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ToyGuy

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I need to run a small dc motor (4.5v) with a sound detection module
Shown here.
sound module.jpg
I don't know how to connect up the digital output pin to drive the motor and it appears that this output varies in voltage from around 2.8 to 3.2 volts which makes the motor run too slow at times. I need the motor to be either off, or full on at 4.5 volts. To complicate matters, the output measures full voltage with no sound and then with sound goes low from 2.8 and up. Searching the internet for info on this module only turns up connections to an arduino which I don't want to use. I'd like to use a minimal of discreet components like a transistor etc.
Any help would be greatly appreciated.
 
How does the output from the device looks like (in oscilloscope) ?

You probably need a latch or delay circuit, depending on your need (how long do you need the motor to run as minimum ?)
 
I'm not electronic savvy so I don't own an oscilloscope. I'd like the motor to run as long as there is sound, then turn off when the sound stops. Mostly the sound will be music, as in a song lasting a few minutes. There will be several songs on a memory chip with silence in between, which is when the motor should stop running.
 
Ok, so you can solve that using a RC low pass filter and a schmitt-trigger, and last an output stage (use a transistor or relay so you don't burn the schmitt-trigger circuit).
 
Thanks Grossel. Is there somewhere that I can find a schematic and parts list for what you are suggesting. I'm really new at this and not following what you are proposing.
 
Do you think I'm getting too complicated by using that sound module? The music is coming from a Mini mp3 player and would be great to go from that to my motor, with some components of course. Perhaps there is a way to connect to a speaker output and filter from there to a transistor?
 

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  • DF mini player-2.jpg
    DF mini player-2.jpg
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Your photos of a sound module and a player have no detailed specifications or link telling what the products are made to do.
I found a cheap sound module like yours at Banggood.
Since it is cheap and is Chinese then it has no details about what it does and how much current is its output.
You also did not say how much current your motor uses. Your motor probably overloads the module.
 
It seems likely that the output from your sound detection module is a digital bitstream. You're not measuring a voltage, you're seeing your voltmeter's response to a signal that's too fast for it to understand.

By all means, start with the speaker output of the player.

I knew a kid in high school. He had the fun idea of putting a siren in his locker which would go off briefly at some point during the day. He bought a "vox box" (voice operated relay) kit from Radio Shack and one of those spring-wound kitchen timers that dings once when time is up. He explained to me how the timer ding was going to briefly close the relay and the siren was then going to emit a correspondingly brief WHOOP! I asked him, won't the siren keep the VOX turned on? You're going to get caught... So, short answer, google "vox circuit".

It depends on whether you want the sound to turn the motor full on and full off or vary the speed. The former case is much simpler. For your "filter" consider a charge pump circuit plus a resistor to bleed down the voltage when the sound goes away. For the transistor, use a MOSFET oversized for your motor. I don't know what your motor current requirement is but an IRFZ44N is a common part that's good for a few amps even with a mediocre gate drive circuit. Make sure the "on" sounds is a loud tone and the off sound is silence. It's critical that the MOSFET gate voltage rises quickly to something above 5 volts when the sound starts and drops quickly back to less than a volt when the sound ends. Don't hook up the motor until you have this part working well or the MOSFET will burn up.

If you want it continuously variable, it's going to get more complicated. How much current does the motor need? What kind of sounds and how is the motor supposed to respond to them?
 
I found some more info on those modules here:

It looks to have a preamp and threshold detector, adjustable by the preset. From that article, the output switches low when sound above the set threshold is detected.

The output could replace a button to ground for a small signal control such as the music player module or similar.

To run a motor, I'd suggest using a cheap timer relay module, eg.

The listing for that says it is triggered by connecting the input to ground, exactly what that sound detector output will do.

You can then use the relay contacts to control the motor.
 
OK, then. I stand (or sit) corrected. The closest thing I found to that module had a UART output.

But the recommended Micro USB Power Delay Relay Timer looks rather suspicious. Surely that description wasn't written by a native English speaker.
 
OK, then. I stand (or sit) corrected. The closest thing I found to that module had a UART output.

But the recommended Micro USB Power Delay Relay Timer looks rather suspicious. Surely that description wasn't written by a native English speaker.

Perhaps you might try reading the dates on the thread? - the last post was from March.

The mike board in the thread isn't a preamp, it's been endlessly discussed in various threads - both modules are incredibly cheap, come from China, and have that countries quality of design and documentation! :D
 
I need to run a small dc motor (4.5v) with a sound detection module
Shown here. View attachment 130211 I don't know how to connect up the digital output pin to drive the motor and it appears that this output varies in voltage from around 2.8 to 3.2 volts which makes the motor run too slow at times. I need the motor to be either off, or full on at 4.5 volts. To complicate matters, the output measures full voltage with no sound and then with sound goes low from 2.8 and up. Searching the internet for info on this module only turns up connections to an arduino which I don't want to use. I'd like to use a minimal of discreet components like a transistor etc.
Any help would be greatly appreciated.
Measure the output with an oscilloscope then share it with us so that we can see the way forward. Thanks
 
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