Hi,

The wiichuck is nice to do testing and prototyping, but it doesn't have a format that can be installed in a robot or in some project.  How do you attach it?  I know it is fairly priced and it is easy to play with, but the format is what makes it impractical for use in projects.

Look at these pictures  http://www.wiire.org/Wii/nunchuk
thats what's when all the palstic is gone...

Eberhard

Hi,

Well, I did say I've only just started this stuff....sorry about the unnecessary question!  

things like that happend to me a lot of times. Doing correct measurings is one of the hardest things in electronics. Whenever I get a strange reading on my meter I examine my measuring setup first. Usually that solves about 80% of the problems already ;-)

Eberhard

Hi,
there should 5V exactly where you expect them between the sockets labeled 5V and GND on the "Power" section.  
That's the theory at least. So you either doing something wrong while measuring (wires to your meter don't have good contact inside the socket on the arduino maybe) or there is a hardware problem.

If you got steady hands maybe you could try to measure the voltage between the pins from the backside. But be careful not to short-circuit the power supply when trying.

Eberhard

Hi,

why 500hz? I haven't used the IDE, but the chip itself can do 62.5KHz with 8 bits of precision.

Its just that way with the arduino. If you use the Arduino analogWrite() function the PWM is at 500Hz. This is not a question of using the IDE or an external Editor, its in the libraries.
(Could be changed, but thats off topic)

Oh, and that circuit limits by cutting volume down when peaks are detected. It works in a completely different way to a couple of diodes. If you supply a constant current to the led, you get constant attenuation to all parts of a signal.

Diode-Limiters are usually sold under the name FuzzBox, MegaDistortion at shops for guitar gear.

Its true that using a combination of Led/LDR for volume-control is common practice (for instance the old-school "Tremolo" guitar-effect works that way), but just not adviseable with the PWM-noise coming  from the Arduino. I can't recommend that for a good quality audio solution.
Eberhard

Hi,

Umm can't control volume with a circuit that controls volume?

http://en.wikipedia.org/wiki/Limiter

what planet are you from? just hook the led to pwm with an rc filter instead of the peak detector...

PWM frequency on the arduino is at 500Hz. You will have a really hard time filtering this nice square-wave noise from you audio signal.

Eberhard

Hi,

I have a different question about controlling volume.  I'm working on a video/sound installation and I'm using a sonic rangefinder to input the distance a person is from the sensor.  What I'm attempting to do is have the volume for the video that is playing to get louder as they get closer.
...

You might be interested in this: http://www.arduino.cc/en/Tutorial/SPIDigitalPot
That basic idea is to put a small audio-preamp that is controlled by on of these digital pots, between the MAC and the power Amp.

I could not find a complete circuit but you might want to try these keywords on Google
"spi controlled potentiometer preamp"
That should give you a few hints.

Eberhard

Hi,

See http://sound.westhost.com/project53.htm which has a great way to control volume from one of the arduino's PWM outputs

The circuit on this page is a volume-limiter. It is used to protect to your speakers from overloading (or in other circumstances) for changing the dynamic of an electric guitar. You can't control the volume with this circuit.

Eberhard

Hi,

Good idea!

I'd like to see an Arduino controlled LED 7 Segment Display clock.

Not really a clock but ...



(code is here http://www.arduino.cc/playground/Main/LedControl)

Eberhard

[current]

Hi w,
here is a link for a page full of midi schematics http://home.concepts-ict.nl/~nctnico/midi.htm
On one of these pages it says that a midi-interface  works by switching a current of ~5mA on and of.
(Switching currents as opposed to switching a Voltage-level is used in areas where there is a lot of (electronic) noise from the outside, like when a band is playing on stage.)

So the 220Ohms is there to limit the current to (roughly) 5 mA. As there is usually an Led on the other end of the Midi-Controler-circuit, I think a current from 3-20mA would be acceptable.

And here is the "official" midi-schematic
http://www.midi.org/about-midi/electrical.shtml
I guess it's the midi-out section you are interested in. This has actually two resitors (plus another one on the midi-in receiver side).

But using only one resistor should be fine.

Eberhard

Hi,
I think I remember that Midi works with some optocouplers? Might be there to limit the current, or as a pull-up, I don't know. Any specific reason why you don't want that resistor to be around?

And .. errrr... what made you think that this is an easy question????

Eberhard

[5V]

Three things I'd like to add:

Current drawn by the Arduino-board:
My NG burns only 60 mA running idle.

Max current drawn from USB:
As already mentioned the Arduino asks for 90 mA. If your circuit draws more than that, it's up to the Hub to decide what to do:
Usually the hub grants up to 500mA, but it is also possible that the hub decides to disable your device.
 
I remember a notebook (Acer?) that granted 500mA for  every device as long as it was powered from mains. But as soon as it ran on batteries it disabled all devices that consumed more current than they initally asked for.
So check with the computer (or UB-hub) you will be using in the end.
 
Power from external 5V source:
If you already use a regulated 5V power-supply you can power the board from the middle pin of the jumper that selects between USB and external Power.
(you remove the jumper and connect the middle pin to plus 5V).

If you get the Voltage wrong (>5V) this kills the board
If you get the polarity wrong this kills your board
If you use an unregulated power-supply the board might run unstable (or gets killed)

The traces should be fine for 800mA.
For safety you might want to add a fuse between the Powersupply and the board.

Check with the arduino schematic.

Eberhard

Yes,
that is the way it's supposed to be
the software makes the Led blink...
then you reset the whole thing...
the arduino checks if there is new sketch to be uploaded, if not :
the software makes the Led blink...

Eberhard

Hi,
I'm using this : http://www.abacom-online.de/uk/html/splan.html
examples drawn by myself are here : http://www.arduino.cc/playground/Main/MAX72XXHardware

It was very easy to get started but comes also with complete libraries. I use it for drawing Guitar-Tabs and Chords too. Very versatile...if they only had a linux version :-(

Eberhard

Hi,
yes it should be possible have a look at these tutorials
http://www.arduino.cc/playground/Main/LEDMatrix

Eberhard

Hi,
simple answer, No!
...and if it were possible its would cost more than buying a digital delay at the store :-(
Sorry
 Eberhard