I am trying to make a simple soundreactive circuit using the following schematic. However, i am using the arduino as a power supply and a single red LED with a 220 ohm resistor in series.
I'm using the Arduino starter kit and I dont have any TIP31 transistors so I am trying to use the IRF520 instead. The circuit does not work, however. Is it possible to replace the TIP31 with IRF520? If yes, how should the headphone wires be connected to the transistor. I use only one of the cables. I connected the bare wire to source and the color insulated one to drain. Tried with swapped places too but there isn't any effect.
Sorry that schematic is too stupid to work. Ditch it and get a real one.
Missed to add some vital information. I edited the question.
That FET will take 10V to turn on so basically it is no use using it with an arduino.
If you want to use a FET make it a logic level one.
Even then the circuit has all the quality of an instructables circuit, that is to say crap.
You have no control over the audio signal other than the volume control and you could damage the audio source by back feeding a voltage into it.
I am trying to make a simple soundreactive circuit using the following schematic. However, i am using the arduino as a power supply and a single red LED with a 220 ohm resistor in series.
Sorry, that's not clear at all...
A 220 Ohm resistor and LED on an Arduino output is fine (without the transistor or FET). For starters, just use the Pin-13 LED that's already on the Arduino board.
Since the Arduino cannot accept the negative half of the audio waveform (the Arduino can be damaged, and/or the audio signal may be distorted) it's common to bias the Arduino's analog input at 2.5V with the circuit shown [u]here[/u]. The two equal-value resistors form a voltage divider that biases the input at 2.5V. The 10uF capacitor blocks that bias from your audio circuit. (You can ignore the 10nF capacitor and the amplifier circuit to the left.)
With bias, silence will read about 512 on the ADC and a sound signal will make readings above and below that. (You can subtract the bias out digitally if that makes sense in your sketch.)
Okay, I will rephrase the question. How can I build a simple one LED sound reactive circuit using the components in the Arduino Starter Kit and a standard audio jack and is it possible at all?
That is tricky manly because the contents of such a kit are unknown to most experienced users. Have you got a link to a list?
Yes, of course. The contents of the kit are listed HERE.
Try this. The pot is the sensitivity control.
That helped a lot! Thank you for the input.
