Side Project Questions:

[KC2UGV]

So, this is a multi-pronged question I pose to all the knowledgeable folks here (And, maybe not even knowledgeable, but idea people too):

I am looking to do a solar powered, Single-Board Computer, with audio out to a low-powered 2 meter transmitter, which is managed via wifi (ie, uploading new audio, forcing a reboot, etc).

The only purpose for this SBC, is to run a small webserver for admin (PHP enabled); and output an audio file to it's audio out. Must be as low-power consuming as possible, and hopefully, inexpensive.

The transmitter, maybe 2 mW. Maybe even a watt, if power loading is minimal (This is a solar powered system, after all).

So, firstly, I'm looking for some sort of Single-Board computer, even if it's a MicroController, which I can bend to my will enough run a minimal webserver, and output audio. The webserver really isn't a requirement per se; but some sort of remote upload of the file via wifi. Any ideas? Can this be done with an Arduino, or BASIC Stamp? Or even a Spin board?

Now, onto the transmitter: I have a Scosche FM transmitter. The kind you get for a car, so you can play your iPod or whatever through your stereo. It's a FMT4R. It looks like much of the xmit circuit can be "bent" to pull it up into the ham bands. I can swap inductors and the like out. Do you guys think it's possible to mod this device enough to get it into the simplex portion of the 2 meter band? If not, are there any plans for a QRP 2 meter transmitter out there?

And, lastly, can all of this be powered via a 5-10W solar panel, coupled with rechargeables? If so, is there is project out there on the web to keep a bank worth of batteries floated with a solar panel, so the kit is powered from the batteries when no sun is out there, and the sun recharging + powering the kit when there is enough sun? Now, for this part, I'm not expecting miracles, and I'll assume I'll need to swap fresh batteries in there from time to time. Looking really to "extend" the battery life, to reduce the number of trips to change batteries out.

This project got it's roots with the WikiTX project, as a manner of proving out the concept (A self-sustained, community radio site). I figured this can be done on the ham bands, as long as I restrict access to hams, and keep content focused for hams.

[NQ6U]

I am by no means an expert on any of this stuff but I've played a bit with the Arduino (and the bare-bones ATmega168 that powers it in other forms) and I don't think there's enough horsepower in them to run a Web server. You may be able to make it work in some other way, though; a place to look for interesting stuff that can be done with the Atmel AVR (http://en.wikipedia.org/wiki/Atmel_AVR) series of microcontrollers is at the Nerdkits (http://www.nerdkits.com/) Web site.

[KC2UGV]

I am by no means an expert on any of this stuff but I've played a bit with the Arduino (and the bare-bones ATmega168 that powers it in other forms) and I don't think there's enough horsepower in them to run a Web server. You may be able to make it work in some other way, though; a place to look for interesting stuff that can be done with the Atmel AVR (http://en.wikipedia.org/wiki/Atmel_AVR) series of microcontrollers is at the Nerdkits (http://www.nerdkits.com/) Web site.

Is there a way to get it running a TFTP server?

[NQ6U]

Is there a way to get it running a TFTP server?

I couldn't hazard a guess on that, it's out of my limited area of experience. I do know that you can purchase a dedicated HTTP server-on-a-chip (http://www.lantronix.com/device-networking/embedded-device-servers/xchip.html) that will interface with the AVR series of microcontrollers. I have never used one, though, so you'd be on your own when it comes to implementing it.

[n2ize]

Sounds like an interesting project. But I must admit, i have absolutely NO experience or knowledge of doing this sort of thing. In any event good luck and let us know how it goes.

[WØTKX]

Would these devices work? Just a little Goggle-Fu for you...

http://www.tgdaily.com/hardware-opinion/41525-marvells-plug-computer-a-tiny-discrete-fully-functional-5-watt-linux-server

http://www.marvell.com/products/processors/embedded/kirkwood/plug.html

[NQ6U]

Here's something that might work. Relatively inexpensive, too--$69:

http://www.modtronix.com/product_info.php?cPath=1_36&products_id=149

BTW, it uses a PIC processor that is probably less powerful than the Amtel AVR series which leads me to believe it might be possible to use an Arduino. However, you'd either have to find the the source code on the Web, then compile and load it or write it yourself. I don't know your abilities when it comes to writing ANSI C code for microcontrollers but writing an HTTP server would be way out of my league. I've mostly just modified existing code. You'd also have to figure out how to interface the Arduino to an Ethernet connection.

[KC2UGV]

Here's something that might work. Relatively inexpensive, too--$69:

http://www.modtronix.com/product_info.php?cPath=1_36&products_id=149

BTW, it uses a PIC processor that is probably less powerful than the Amtel AVR series which leads me to believe it might be possible to use an Arduino. However, you'd either have to find the the source code on the Web, then compile and load it or write it yourself. I don't know your abilities when it comes to writing ANSI C code for microcontrollers but writing an HTTP server would be way out of my league. I've mostly just modified existing code. You'd also have to figure out how to interface the Arduino to an Ethernet connection.

That should work I think... I like I can even plunk in a daughterboard. I could use that to build the audio out circuits...

[WØTKX]

Cool little chipsets out there, eh?


http://www.youtube.com/watch?v=cFods1KSWsQ

[KC2UGV]

Cool little chipsets out there, eh?



Yeah. I think there might be an audio module for it too, to boot :)

[NQ6U]

One great thing about the Island: Even when we don't know the answers off the tops of our heads, our collective Google-fu is awesome. Try asking your question on the Zed and see what kind of crap you end up with.

[KA5PIU]

Hello.

As far as the FM transmitter idea, forget about the broadcast transmitter, FM broadcasting is very much wideband, 200 kHz worth of wideband!
For a transmitter you can use a sinewave oscillator that you modulate and buffer to the few milliwatts, or buy one of the little crystal controlled "spy" transmitters.
Depending on how large your solar panel is you can run pretty much anything.
AT&T has switched out thousands of old analog telephone repeaters, and a lot had a solar array that has turned up surplus.
Look around on the surplus market and see what you can find.

[KC2UGV]

After some more researching, looks like most of the legwork has already been done:
http://alyer.frihost.net/ethradio/eth_radio_en.htm

Now, looking for the QRP 2 meter plans...

[mw0uzo]

That project looks great, a good mcu plus theres a TCPIP control program available! That would be a lot of hard work coded from scratch..

[NQ6U]

After some more researching, looks like most of the legwork has already been done:
http://alyer.frihost.net/ethradio/eth_radio_en.htm

Now, looking for the QRP 2 meter plans...

Interesting. The author implies that there is an embedded Web server in the ATMega microcontroller, something that I was certainly not aware of. I'm going have to look into that a little deeper.

[KC2UGV]

Well, I've been tinkering with some of the microcontrollers, and none of them seemed to be beefy enough, or have most of the hardware already available (Sound out is a tough one, without resorting to writing a A/D module).

So, in the spirit of "Hack-a-thon", I think I've found my solution: Android OS. I've been able to procure an Archos 28 for $79. The thing has a 600MHz processor, audio out, ad-hoc(able) wifi, charging system, and basically everything pre-built short of the transmitter section.

It can charge itself off a decently sized solar array/wind turbine (Gotta have more than one way to power), with some juice to spare for the transmitter. Apache is already pre-built for Android 1.6+, so it's a go there. Need to build fastcgi for ARM, and we should be good to go with the Wiki software to get loaded :)

It's moving along :)