Re: [Discuss-gnuradio] Yet another kick at the cheap-hardware can

[Moeller]

On 20.01.2011 00:23, Marcus D. Leech wrote:

> If the answer to the above is "yes", then the next question is:  is
> there a community of interested
>   volunteers to bring the project to fruition?  Such an interested
> community would involve:

I'm interested in developing a SDR teaching platform, especially
for introducing electronics to children. I tried it with simple
logic circuits and blinking LED, a simple FM radio (surely no Hifi).
But kids today grow up with MP3 players, computers and other high tech
electronics. They expect electronics to be more fascinating.
So, what's more attractive than stupid blinking LED experiments?
The Gnuradio RADAR experiment? Looking into the wide radio spectrum?
Visualizing radio emissions of electronic devices, the microwave oven,
car key, mobile phone, ... ?
As a child, I was very fascinated with my analogous oscilloscope,
analyzing and repairing all kind of devices. I think nowadays, after
so much progess in technology, it should be a device like Gnuradio.

>      o High-level hardware design

I'm thinking of a scope frontend, with switchable voltage levels.
Maybe my old scope schematics (was an appendix to the user manual)
could give inspiration. At least I would use a circuit for overvoltage
protection and an attenuator (in front of the first LNA).
It does not have to be integrated on the PCB, possibly only an
additional box in front of the antenna input.
I don't mind if there is no DC coupling.
The power levels could be calibrated in software.

>      o Detailed schematic capture and PCB layout

I installed KiCad (http://kicad.sourceforge.net/).
My first impression was very positive, especially with
the FPGA example project.

>      o FPGA firmware design

used it for glue logic circuits before, in VHDL ...

>      o Host-interface (FX2?) firmware design
>      o Host driver software design and implementation

I suppose there is also public domain software available.

>      o Small-scale financial investment for initial PCBs, components, etc

I don't mind if a board of $100 explodes during debugging.
As I child I burned many semiconductor devices.
Our local PCB manufacturer asks 50€ for prototype boards. I could try with one.

> Once such a board works, then someone needs to be found to distribute
> either kits or finished product.

There are electronics and amateur radio magazines that distribute such kits.
Up to now they offer only simple soundcard-based solutions. I'm sure to attract
more readers they will be happy to publish articles and distribute kits
with new innovative designs.

In development countries it could be adapted to the local price level.

> Something that vaguely compares to this effort is the FunCube Dongle,
> which is a quadrature
>   receiver covering 64MHz to 1.7GHz, but with 96KHz host-side bandwidth.
>  That project is selling fully-built units for about USD 170.00.

Sold out in a few minutes after starting the offer.
Apparently there is a huge market for cheap SDR devices.