| Author |
Message |
Ike
Guest
|
 Posted:
Thu Nov 17, 2005 9:35 am Post subject:
Electret Mic to Drive Logic (Clap or Whistle) |
|
|
What is the easiest way to drive a logic high input pin on a
microcontroller with an electret microphone?
I want the microcontroller to be able to detect a clap or whistle or
any spike in sound pressure. Sound quality and frequency are not
important.
The catch is that the circuit MUST run from a single 3v lithium CR2
battery.
The microcontroller is a 12F675 and it has an ADC, so I could use the
ADC if it is not practical to get 2.5v to 5v for a digital input pin.
But I think I still need to boost the electret's output for the pin to
be able to detect a change.
|
|
| Back to top |
|
 |
John Fields
Guest
|
| Posted:
Thu Nov 17, 2005 5:35 pm Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
On 17 Nov 2005 00:39:39 -0800, "Ike" <ikenewton@gmail.com> wrote:
| Quote: | What is the easiest way to drive a logic high input pin on a
microcontroller with an electret microphone?
I want the microcontroller to be able to detect a clap or whistle or
any spike in sound pressure. Sound quality and frequency are not
important.
The catch is that the circuit MUST run from a single 3v lithium CR2
battery.
The microcontroller is a 12F675 and it has an ADC, so I could use the
ADC if it is not practical to get 2.5v to 5v for a digital input pin.
But I think I still need to boost the electret's output for the pin to
be able to detect a change.
|
---
View in Courier:
+3V>-----+-----------+------+-------+
| | | |
[3k3] [1M] | |
+----+ | | | |
| |--+--[0.1µF]--+------|------|+\
|MIC | | | | >--->Vout
| |--+ | [1M]<---|-/TLV
+----+ | [1M] | | 3701
| | | |
GND>-----+-----------+------+-------+----->GND
The 3.3k resistor might have to be changed depending on the mic you
use.
With no sound into the mic, adjust the 1 meg pot until Vout goes
high, (about 1/2 scale) then back off until Vout goes low. Then,
with sound into the mic, adjust the pot for the sensitivity you
want.
--
John Fields
Professional Circuit Designer |
|
| Back to top |
|
|
Ike
Guest
|
| Posted:
Sat Nov 19, 2005 12:12 am Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
Hi John...
Wow, I really appreciate your post with this circuit! This will work
perfectly!
I can't seem to find a TLV3701. TI lists it as obsolete, and I can't
find a source at the standard outlets (Mouser, Newark, Jameco, etc.) or
on Google. DigiKey lists them, but they don't have the PDIP as a stock
item (I can't use SMD at this time).
Is there another device that can be subbed?
Thank you!
|
|
| Back to top |
|
|
John Fields
Guest
|
| Posted:
Sat Nov 19, 2005 12:58 am Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
On 18 Nov 2005 10:12:48 -0800, "Ike" <ikenewton@gmail.com> wrote:
| Quote: | Hi John...
Wow, I really appreciate your post with this circuit! This will work
perfectly!
I can't seem to find a TLV3701. TI lists it as obsolete, and I can't
find a source at the standard outlets (Mouser, Newark, Jameco, etc.) or
on Google. DigiKey lists them, but they don't have the PDIP as a stock
item (I can't use SMD at this time).
Is there another device that can be subbed?
|
---
TLV3702IP. It's a dual, so you'll have to spare one comparator.
Digi-Key has 136 of them them in stock for $2.25 each.
--
John Fields
Professional Circuit Designer |
|
| Back to top |
|
|
Ike
Guest
|
| Posted:
Sat Nov 19, 2005 1:35 am Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
Hi John...
Excellent! Actually, when I searched for your reference to "TLV3702IP"
I found the "TLV3701IP" which is not obsolete! I'm not sure how I
missed that one. I have ordered samples from TI.
Is there a way to achieve this functionality with transistors?
Thank you! |
|
| Back to top |
|
|
John Fields
Guest
|
| Posted:
Sat Nov 19, 2005 1:35 am Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
On 18 Nov 2005 13:15:55 -0800, "Ike" <ikenewton@gmail.com> wrote:
| Quote: |
Hi John...
Excellent! Actually, when I searched for your reference to "TLV3702IP"
I found the "TLV3701IP" which is not obsolete! I'm not sure how I
missed that one. I have ordered samples from TI.
Is there a way to achieve this functionality with transistors?
|
---
At the quiescent supply currents involved, I'd say "no".
---
---
My pleasure. :-)
--
John Fields
Professional Circuit Designer |
|
| Back to top |
|
|
Ike
Guest
|
| Posted:
Sat Nov 19, 2005 9:35 am Post subject:
Re: Electret Mic to Drive Logic (Clap or Whistle) |
|
|
Hi John...
I just found this circuit...do you think this circuit will work?
http://www.csmrobotics.com/mic_amp_02.gif
Thanks! |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in