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1  Using Arduino / Programming Questions / Re: SoftwareSerial problem , but only on 1284p on: December 17, 2013, 11:28:16 am
I am having a different issue.  I am trying to use the softserial library with a 1284P using the mighty1284 core.  The sketch I have works with the UNO but as soon as I try to compile it with the "Bobduino" I get the following:

C:\Program Files (x86)\Arduino\libraries\SoftwareSerial\SoftwareSerial.cpp: In member function 'void SoftwareSerial::begin(long int)':
C:\Program Files (x86)\Arduino\libraries\SoftwareSerial\SoftwareSerial.cpp:401: error: operands to ?: have different types 'int' and 'uint8_t*'

These errors are caused by a type mismatch. The type int is not the same as uint8_t*.   int is, well, an int, while uint8_t* is a pointer to an 8 bit unsigned int (which really means something like unsigned char * - I would have to look in the header but I have to go out the door soon).

What is odd is that it works with the Uno.

I can attest that SoftwareSerial works with Mighty 1284P as well as Software Serial can work (which is to say, not very well). There is either an error in your version of SoftwareSerial or your Mighty1284 distro. In fact, are you using the very same code in the Uno and the Mighty1284P?  If you have two different versions of Software Serial (one for Uno and one for Mighty 1284P) then the fact that you can build for Uno is irrelevant.

I see I made a promise a while ago I failed to keep. I still have the modified header files for SoftwareSerial on 1284P, and I can share. But I need to run now :-(
2  Topics / Science and Measurement / Re: O Scope recomendation on: August 19, 2013, 03:41:33 am
If you're running 400 KHz I2C, that units 1M (1000 KHz) samples/sec will not tell you much about the signals - you'd want something that can do 4M (4000 KHs), otherwise you  barely see more than a high & low each clock signal.


Okay thanks for pointing that out. No point in getting something that's useless...

Wow, those scopes are really, really cool. I guess scopes have improved a bit since the junker Tektronics I got at a ham radio flea market a few decades ago...


3  Topics / Science and Measurement / Re: O Scope recomendation on: August 19, 2013, 03:24:35 am
Bob, that's nice looking hardware, but I don't want to spend ~$400 right now. Although I do admit, I spent more than I wanted on the Logic 16 and it worked out great. I had something like this in mind:

http://www.gabotronics.com/development-boards/xmega-xprotolab.htm

Thats pretty inexpensive at about $50, and I can go higher if I need to. I'm just not sure exactly what I need. I'll probably be mostly playing with it, although it would be handy to look at I2C busses and so on to see if the signals are clean.
4  Topics / Science and Measurement / O Scope recomendation on: August 19, 2013, 12:05:36 am
Hi All...

I would like to get a decent O Scope for general project use. I expect the affordable option would be one that plugs into a PC for the display and data processing, like the way the Salee Logic 16 works.

Any suggestions?

Thanks...
5  Using Arduino / Audio / Re: Storing data in an audio channel on: August 11, 2013, 01:08:50 am
Barker code looks interesting, thanks. I could also fill dead time with random data. I think what will happen is that the loss will reduce my mit rate, but I can probably find a modulation technique and data rate that works reliably.

Thanks everyone! This is very helpful...
6  Using Arduino / Audio / Re: Storing data in an audio channel on: August 10, 2013, 04:23:45 am
Basically you need a modem of some sort. The data rate is determined by the modulation method. A simple on / off of a tone will give a data rate the same as half the audio bandwidth. By having quadrature modulation and amplitude modulation on top of that you can extend the data rate to be multiples of the audio bandwidth.

Well thats good news, thanks! More good news is that the audio bandwidth is 48KHz per channel. Sadly, the bad news is that it records directly to a memory card and it uses AAC, which uses lossy compression. Grumpy Mike, do you know of a modulation technique that can get around lossy compression? I'm Googleing with no luck :-(
7  Using Arduino / Audio / Re: Storing data in an audio channel on: August 07, 2013, 01:30:10 am
Aren't most audio channels on video recorders, and other things not intended for high quality audio, 3 KHz?
 
8  Using Arduino / Audio / Re: Storing data in an audio channel on: August 05, 2013, 05:21:12 pm
Thanks everyone, this is all very helpful!

For decoding in hardware I could use the XR2211. Years ago (more than I care to admit) I used the XR2211 and XR2206 to build a radio teletype (RTTY) terminal unit for my HF ham rig. Worked great. These days, such a thing is obsolete.

So at 1.5Kbit/sec (assuming a 10 bit byte for stop bits and such) I could store 150 bytes per second, which would do.

Decoding will (hopefully) be done by software that reads the digital video and extracts the data from the audio channel. This seems like the hard part.

Corssroads, I am a bit confused, were you saying I don't need a modulator chip?

9  Using Arduino / Audio / Storing data in an audio channel on: August 05, 2013, 02:35:11 am
Hi All...

I am trying to think of the best way to store data in the audio channel of a video recorder. My first thought is to use a chip like an XR2206 to convert a data stream to audio tones and just inject it into the mic input. I assume I'll need some impedance matching and level adjustment. I have been Googling with little luck, does anyone know of a reference circuit for something like this?

Also, would I use the Nyquist theorem to determine the maximum data rate I can encode in a 3KHz audio channel?

Thanks...
 
10  Using Arduino / Networking, Protocols, and Devices / Re: Update on DASH7 on: August 04, 2013, 06:41:34 pm
That would be great, thanks. I like that you included so many options for talking to it. My personal favorite is I2C. Will this board be able to talk to your Haytags?
Yes, they can talk to HayTags, although HayTags in private use will probably have most of the data secured by encryption keys that you don't have.  If you buy some HayTags of your own, you can configure them to use no encryption, or just copy the key into this dev kit.  This can be done during runtime, i.e. it is not necessary to compile the keys into the image.

That's what I meant. I want to buy some Haytags and have a way of tracking them with my own hardware. Any idea when this might all be available?

11  Using Arduino / Networking, Protocols, and Devices / Re: Arduino to Arduino using Bluetooth on: July 31, 2013, 12:55:42 am
I see plenty of Arduino to PC communication using a bluetooth transceiver and also the Arduino BT, but is there a way to use two Arduinos each with their own bluetooth transceiver to send information back and forth? I'm looking into alternatives for RF communication.

Yes and its not even difficult. The key is that you need a transceiver that can be a master and one that can be a slave. The Seedstudio bluetooth shield can be either. They even have a tutorial on making two Arduinos talk to each other using bluetooth here:

http://www.seeedstudio.com/wiki/Bluetooth_Shield

12  Using Arduino / Networking, Protocols, and Devices / Re: Update on DASH7 on: July 31, 2013, 12:51:36 am
That would be great, thanks. I like that you included so many options for talking to it. My personal favorite is I2C. Will this board be able to talk to your Haytags?
13  Topics / Home Automation and Networked Objects / Re: Adding a Bluetooth board to the official Arduino lineup on: July 29, 2013, 08:49:01 pm
Hi Guys...

Can this board be a master, so it can take the place of the iPhone, or can it only be a slave?
14  Using Arduino / Networking, Protocols, and Devices / Re: Update on DASH7 on: July 29, 2013, 08:34:49 pm
Are any of these modules still available?
15  Using Arduino / Project Guidance / Re: Child Proximity Band?? on: July 29, 2013, 08:13:30 pm
I know this is an old thread, but:

http://www.button-trackr.com/

And also:

http://www.thetileapp.com/

And even:

http://haystacktechnologies.com/


The first two use Bluetooth low energy (BLE) which has specific profiles designed for this type of thing. Distance between the master and slave can be a max of about 150 feet and you know how far away they are based on RSSI (receive signal strength indicator). This estimates distance but not direction.

The third uses a different system called DASH7, which has some nice advantages over BLE for this type of thing. The biggest advantages are range (maybe a quarter mile) and better battery life. Like the BLE systems, it uses RSSI and has the same limitation that it tracks distance and not bearing.

Personally, I don't see much use for any of these things at their current price points, although putting one on a child is probably the best use I have seen suggested. Still, if the child moves out of range of the master its not useful at that point, and I don't see the proposed network of smart phones being dense enough (not even close) to find anything.  Tile has been getting some press, but people do not seem to understand exactly how limited it is.

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