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16  Using Arduino / General Electronics / Re: Trouble powering arduino and amplifiers from the same power source on: September 30, 2014, 07:02:34 pm
To keep noise (current pulses) on the 5V line from affecting all the circuits. That Class D amplifier works by PWM switching, yet has only 10uF and 0.1uF bypass (aka decoupling) capacitors.

Bottom right, C1 and C6 from Vdd to ground.



Yes, there appears to be a 10k resistor on the board to 5V (labeled 1002) so 1k should pull that line down. Or you could remove that 10k resistor and then you can use a higher value resistor like 10k or more to pull it to ground. If you use larger than 100k, I'd also place something like a 1nF or 10nF (0.01uF)  capacitor across the resistor to ground.

http://www.analog.com/static/imported-files/tutorials/MT-101.pdf

http://www.seattlerobotics.org/encoder/jun97/basics.html

http://www.intersil.com/content/dam/Intersil/documents/an13/an1325.pdf

17  Using Arduino / General Electronics / Re: Can anyone convert this schematic into a fritzing project? on: September 30, 2014, 06:52:39 pm
This will be an excellent time for you to learn how to read schematics. Seriously.
18  Using Arduino / General Electronics / Re: Trouble powering arduino and amplifiers from the same power source on: September 30, 2014, 05:36:13 pm
There is a Shutdown pin on that amp. Have the Arduino only enable it after the Arduino has fully booted up.

http://www.adafruit.com/datasheets/MAX98306.pdf

That is the SDWN line on the PCB.



And probably add a lot of bypass capacitors and a large electrolytic capacitor to the 5V line.
19  Using Arduino / Project Guidance / Re: Beginner question: stuck with a problem on: September 30, 2014, 01:59:15 pm
That looks like a pull-down resistor with a pull-down switch. So it will always look like the switch is pressed. Remove the 10k resistor that is on the pushbutton switch, and use the internal Pullup resistor as suggested.

Or connect the right side of the pushbutton to 5V.

The fact that the LED lights up when you remove the button would seem to indicate that you have the switch turned 90 degrees.
20  Using Arduino / General Electronics / Re: Help! Get a signal from Arduino Uno into the computer on: September 30, 2014, 01:53:54 pm
What did you do to solve the problem?
21  Using Arduino / Project Guidance / Re: DRO component list help on: September 30, 2014, 09:24:37 am
I think most of the Arduino CNC stuff out there is based on stepper motors.

I'm very interested in seeing servo controlled CNC with an Arduino. It might require one of the ARM based Arduinos or variants like the Yun or Teensy 3.1.

For those who may only picture RC servos when we say servos - a servo-motor is basically any AC or DC (usually DC brushless, which is really an AC motor with semiconductor commutation) with position feedback. Most of the really big CNC machines use this rather than stepper motors.
22  Using Arduino / General Electronics / Re: Arduino Tester - Fault 'Cell!' on: September 29, 2014, 06:36:48 pm
Translated:

http://translate.google.com/translate?hl=en&sl=de&u=http://www.mikrocontroller.net/articles/AVR_Transistortester&prev=/search%3Fq%3Dtransistortester.tar.gz%26hl%3Den%26safe%3Doff%26client%3Dfirefox-a%26hs%3DILT%26rls%3Dorg.mozilla:en-GB:official&sa=X&ei=PYQpUbfWMenD0QWrn4GQCg&ved=0CFMQ7gEwBA
23  Using Arduino / General Electronics / Re: Arduino Tester - Fault 'Cell!' on: September 29, 2014, 06:35:17 pm
There is a very long thread on EEVBlog forums about this component tester:

http://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/

Moderator edit: URL corrected
24  Using Arduino / General Electronics / Re: Arduino Tester - Fault 'Cell!' on: September 29, 2014, 06:29:42 pm
The one you have is called an AVR-TransistorTester, or is based on it.

http://www.markus.org/Electronics/Projects/AVR-Transistortester/

http://www.mikrocontroller.net/articles/AVR_Transistortester

I have a similar device, also from eBay. There seem to be quite a few variations, mine looks like this:



The Ardutester is a port to the Arduino.

http://forum.arduino.cc/index.php?topic=164112.0

What I'm getting at, is what you have is not an Arduino, and that you can probably download the C code if you are unable to get the program off of that 328.
25  Using Arduino / Project Guidance / Re: DRO component list help on: September 29, 2014, 05:57:03 pm
OK, so you have a quadrature output, aka sine/cosine output. This is the same output from rotary encoders, so a good place to start is here:

http://playground.arduino.cc/Main/RotaryEncoders

26  Using Arduino / General Electronics / Re: Problems determining Voltages needed to run a fuel tank level sender. on: September 29, 2014, 05:54:17 pm
I hope you understand that the kind of sender this appears to be from your description requires the resistance of the meter itself as part of the circuit , and is not intended to have 12V connected directly to it or it will burn up when it is in the Full position.

I think the way I'd use it would be to connect a relatively large resistor in series with it and measure the voltage drop across the sender. If the resistor is 10 or 20 times the resistance of the sender's highest resistance, the reading should be relatively linear, as long as the resistance change is linear.

Keeping in mind that the resistance may -not- be a linear function of position, it may have been wound so that, in conjunction with the fuel gauge resistance, the fuel gauge position would be fairly linear.

27  Using Arduino / Project Guidance / Re: Transmit tone at 315Mhz on: September 29, 2014, 01:37:10 pm
Sure, it has its uses. But newbies are being taught to do everything using delay(). Then as soon as you try to combine more than one function, things grind to a halt and they have to relearn everything.
28  Using Arduino / Project Guidance / Re: Transmit tone at 315Mhz on: September 29, 2014, 12:46:46 pm
If that is all you want to do, a 555 timer is the simple solution. No extra transistor needed, even.

If this is you learning how to use radio modules, then by all means use an Arduino. But please SKIP USING DELAY! Look at the "Blink Without Delay" example sketch, or use the tone() command. Using delay() is a terrible idea, as you'll only be learning a bad habit.

http://opensourcehardwaregroup.com/arduino-short-course-public-pages/section-3-digital/tutorial-16-blink-an-led-without-using-the-delay-function-old-version/

http://www.baldengineer.com/blog/2011/01/06/millis-tutorial/

http://forum.arduino.cc/index.php?topic=223286.0
29  Using Arduino / Project Guidance / Re: Is Teensy the answer for video processing ? on: September 29, 2014, 12:40:08 pm
The Teensy 3.0 and 3.1 are not just another Arduino. It is an ARM Cortex M4 at 96MHz (48MHz), but it is only 64k of RAM (256k Flash) versus the 512MB of RAM and 700MHz CPU and GPU that the Raspberry Pi B has on it.

HD video, or old 4:3 video?
30  Using Arduino / Project Guidance / Re: Is Teensy the answer for video processing ? on: September 29, 2014, 11:13:49 am
The Teensy 1.x and 2.x are 16MHz, basically a standard Arduino. The Teensy 3.x is the one with a 96MHz ARM Cortex M4 on it.

What kind of video processing?  This might be better asked on the Teensy forum at:
http://forum.pjrc.com/
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