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16  Using Arduino / Project Guidance / Re: Music Visualizer Project : Extracting data from computer's audio buffer on: January 17, 2014, 04:11:21 pm
I've done this before. Here's my blog article from 2011 with code examples:

On Windows and Linux, you can try to set Stereo Mix as your recording device in the audio settings. On Mac, I have used Soundflower to do the same can set it as an output device, and then it lets you also select it as a recording device while monitoring the audio stream to the system audio device (same thing Stereo Mix does on Windows).
17  Using Arduino / General Electronics / Re: Working with 5v component(s) in 3.3v Arduino? on: January 07, 2014, 05:14:20 pm
Just confirming that you shouldn't have any problem at all...both the DHT22 and the ChronoDot should work as-is on 3.3V.
18  Using Arduino / Networking, Protocols, and Devices / Re: Question about the centipede shield on: December 29, 2013, 04:11:57 am
JimboZA is correct, the other pins all pass through the shield. The only four pins connected to the Arduino are A4, A5, 5V, and GND.
19  Using Arduino / LEDs and Multiplexing / Re: RGB with two pins on ATtiny85 on: November 25, 2013, 03:39:37 am
This is a great hack to save a pin, but please note it is at the expense of about 50% brightness.
20  Using Arduino / LEDs and Multiplexing / Re: Driving Multiple WS2801 LED Strands Quickly on: November 25, 2013, 02:47:07 am
It's probably not going to be faster, and not worth pursuing unless you absolutely must have them synchronized. Here's why. The WS2801 is a clocked shift register input, so it's much more relaxed than the WS2811 for bit timing. So you're hoping that you can just present the current bit for all of the strings, possibly as a port write instead of a pin write....that would make sense, if that was all you had to do. In order to prepare the bits for transmission, you still need to increment through each of the output bytes, do the bitshift, grab the bit you want, and store it into a variable that you'll write to the port later. It ends up being almost the same amount of cycles to do all that preprocessing, versus just doing a normal SPI write.

Here's one way to gain a lot of speed. Use the SPI hardware output peripheral, and set up a demux IC to aim the SPI clock output at one of the strips. Then you just drop a byte into the SPI register, let the hardware do the sending, aim the demux at another strip, and fire away. Probably 100% speedup over a software-only approach.
21  Using Arduino / Project Guidance / Re: Serial communication problem on: October 28, 2013, 02:17:16 pm
Please note that the mini-USB port is connected to an FTDI converter, which has RX and TX pins connected to the Arduino's RX and TX pins. So when you attempt to use the Arduino USB serial monitor along with something else on the RX and TX pins, you'll see conflicts. It's absolutely no surprise that code download would be a problem with the motor controller also attached to those pins.
22  Using Arduino / Project Guidance / Re: arduino as serial client? on: October 28, 2013, 02:13:27 pm
The Arduino is currently using serial over USB, but what you want is RS232 (which is more of a communication voltage standard as applied to serial comms). The TTL-serial data from your Arduino needs to be converted to RS232 levels, which is something like +/- 9 to 12 volts. Usually, people use a MAX232 chip (or compatible, they're cheaper) which is designed for this exact purpose. It would require soldering up a PCB with some capacitors etc. But there are premade shields for this, Sparkfun has one:

However, you'd need to remove that shield in order to program the Arduino through USB. There may be other shields out there that allow you to switch the RS232 connection on and off, or let you tie to other pins and use SoftwareSerial instead of the hardware ports.

Once you have the electrical side of things figured out, the rest is easy...just use some the Arduino serial examples. A "Serial.println("get ip");" might be your start.
23  Using Arduino / General Electronics / Re: Using Microchip MCP2200 instead of FTDI FT232 on: October 18, 2013, 02:09:15 pm
I can see why you would want to be able to control the GP pins from the USB side, for things like MCU hard resets - but to make them uncontrollable from the UART side seems madness...

Madness? THIS. IS. RS232.

It's a byte pipe. USB is able to control the GPIO pins because it sees the FTDI device as a structure with various elements, just one of which is a serial data link. On the uC side, it's just a hose containing bytes, there's no method for out-of-band signaling of other functions. Would you want the FTDI chip to contain some magic sequence of bytes that triggers the GPIO? What if in the course of transferring other data, that magic sequence occurs? Not a good idea.
24  Using Arduino / General Electronics / Re: Using Microchip MCP2200 instead of FTDI FT232 on: October 17, 2013, 03:51:19 pm
I can confirm that the FT230X works fine for Arduino programming, with no configuration needed. DTR support works fine. It's what I use on the LED Shades. Keep in mind that it is a 3.3V part, though.

The last I heard about the MCP2200, it didn't have correct support for the DTR line, at least in the Windows drivers...the Windows CDC driver left much to be desired, and that's what the MCP2200 leverages (the FTDI chips use their own VCP driver). Things may have improved since then.

Edit: Actually, I'm using the RTS line, not the DTR line. That works because so many FTDI adapters (including FTDI's own cables) broke out the RTS line instead of the DTR line. Therefore, avrdude has triggered both DTR and RTS at the same time to reset Arduinos for programming.
25  Using Arduino / LEDs and Multiplexing / Re: Problem with ShiftPWM and RGB LEDs on: October 14, 2013, 05:37:55 pm
Yes, this is thread drift smiley I'm just promoting mental flexibility, people love to box themselves into rules that apply to a specific subset of reality, and then generalize them onto the rest of it.
26  Using Arduino / Project Guidance / Re: Arduino based handsfree/headset for Android on: October 14, 2013, 01:37:26 am
It seems that the best way to do this would be to start with a Bluetooth earpiece. It already has most of the functions you need, you'll simply need the electronics to interface the speakers, ringer, and switch to it. Then just use the built in Bluetooth headset functions on the phone.

Your project is basically a combination of the popular Bluetooth handset hack, and Sparkfun's Port-o-Rotary phone project. You'll find most of the relevant information and electronics in those two projects.
27  Using Arduino / LEDs and Multiplexing / Re: Getting the Teensy to recongize the LED's on: October 14, 2013, 01:31:43 am
You might be able to do this by attempting to read the LED voltage using an ADC, but that may not tell you anything because LEDs are made using various chemistries. The only reliable way to do this would be to use a color sensor chip and aim it at the LED. You'll find that to be a much more expensive and complicated project.
28  Using Arduino / LEDs and Multiplexing / Re: Problem with ShiftPWM and RGB LEDs on: October 13, 2013, 08:29:55 pm
This is the best answer for small electronics systems, but don't file it away as an absolute rule because it'll cause a lot of cognitive dissonance when you see a power system that uses actual dirt as a return line.
29  Using Arduino / LEDs and Multiplexing / Re: 1 Arduino with 6 Neo_Pixel60 on: October 11, 2013, 02:13:17 pm
I'd recommend using a Teensy 3.0 instead. The OctoWS2811 library will drive 8 strips at the same time.
30  Using Arduino / Programming Questions / Re: problems with ds1307 and arduino uno on: October 10, 2013, 03:48:39 am
Perhaps this is a hardware problem? Are you sure that your DS1307 has power, the correct crystal, is running, has I2C pullup resistors, etc?
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