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Topic: control dc motor with a mic! (Read 2199 times) previous topic - next topic


Hello! I have just figured out my first arduino project.. what i want to do is control an 18v DC motor (from an old screwdriver) with a microphone. What im gonna do with this motor is roll up my curtains in my room which activates when my alarm on my cellphone (or alarm clock) goes off in the morning or when i please.

Now to the question: I read some guide on here that said i could use an H bridge to do this.. can i do it in another way?

When i first came to think about this idea i thought of powering the dc with an external power source and just have a transistor in between to control the on and off as thats all i really need.. and to use the microphone input as an indicator of when the arduino powers the transistor which then lets the motor run.

As im new to this i dont really know if that will work.. though with my basic knowledge i like to think that it would work just like that (i thought about having to use an amplifier for the microphone too). So where im going with this is that im unsure whether or not i can do it this way or if i really have to use a bridge? I just want to know if this would be safe for the arduino or if i should do it in another way.

I really appreciate if you guys have any other ideas on how to do this aswell.

thanks in advance! /anton


Mar 19, 2013, 12:30 am Last Edit: Mar 19, 2013, 12:54 am by Lakes Reason: 1
This will give you some ideas for arduino audio input.


Get that working first, and then think how you want to control the motor, do you need to just open the curtains?
If so a simple relay will do the job, but you need a (light level) sensor to detect when the curtains are open enough.

So, detect audio level, switch on motor, detect light level, switch off motor.



Mar 19, 2013, 01:46 am Last Edit: Mar 19, 2013, 01:55 am by TrailerTrash Reason: 1
3 Pin Sound Sensor Module ECM for Sound Detecting 5V DC DIY High Sensitivity


So i have put together a clap switch for my project, http://www.buildcircuit.com/clap-switch2/# and i was trying out different resistors (R5 in the circuit) to increase the sensitivity of the mic, because i have to be close to the mic when i clap.. so with the different resistors i tried (ranging from 1k to 10k) im not seeing any of the results that i want.

so my question is should i get another transistor that is more sensitive or is there anything i can do to amplify the signal if i connect it to my arduino (somewhere inbetween the mic and the transistors) ?

any thoughts or ideas is very appreciated!

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