Hi all,
I realized a LED strip controller that reacts with sounds thanks to the sparkfun electret mic board.
It was all working perfectly until I switched power from USB to the external power connector. Without USB power Leds began to flash themselves ignoring the mic connected to analogpin 0.
Then I tried to use a bare atmega328 on a breadboard powered with a 7805… .same problem.
So I tried to give 5V from 7805 to the USB connector on Arduino and it began to work again perfectly flashing only with sounds.
My question is: there is a way to make the bare atmega working as USB powered Arduino?
Thanks
bye
Davide
How bare was your ATmega ? Did you have a crystal or resonator ? How did you load your code into it ? If this was the same code as you developed on an Arduino (my assumption given the forum, you did not specify), was the bootloader pre-loaded ? When you say you “switched power from USB to the external power connector” was that with an Arduino ? What voltage input did you use ? Can you provide a schematic or wiring diagram of some sort. It’s hard to tell whether your design is some deficient or you didn’t input the right voltage or if you missed some Vcc or ground connection in going from the Arduino to the bare 328. There’s just too many ways a simple mistake could have crept in.
Hi,
my at mega schematics it’s that one http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard
however i have the same problem with a real arduino powering it from the 9-12V connector but not if I power it from the usb connector.
I even tried to take 5V from a 7805 and give the output to the usb connector… even in this way it works correctly.
So it seems that there is something in the USB circuit that makes analog input(or the mic) to work correctly.
However all digital functions in the barebone Arduino works perfectly, I only have problems with analog values coming from the mic.
Bye
Does your mic take power ? Or is there some pre-amp between the mic and the analog input pin ? If so, where did you get that voltage from ?
The mic it’s that http://www.sparkfun.com/products/9964
It take power from the 7805 in the breadboard version of Arduino, or from the 5v pin from the real arduino.
In the breadboard version I cannot try powering the AtMega from USB because I don’t have a stand alone interface, but with Arduino works only with usb power. To drive leds I used mosfets RFP30N06L connected to pins 5 and 6 in pwm. With USB power Leds flashes with sounds as they should do but if I whitch to external power, leds begins to flash ignoring mic signal.
I found the problem!
It was some rf noise being amplified by the mic circuit. I solved with shorter wires to the mic vcc.