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Conundrum

Sat Sept 22 2012, 06:14AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Hey guys and gals..
Anyone here got a Pi? Done anything interesting with it?
Post it on here.

So far I have about 4 projects planned with mine, the main annoyance is
that the SD slot isn't very robust long term with only 1000 rated cycles.

I did look into making a "Portable Pi" using a defunct P*na*onic DVD
with the Pi generating eye signal data using the HDMI port.
This could work with just the onboard CVBS output though, turns out that if
you add a very simple stripper circuit with an LM1881 and a JFET it will output
arbitrary data with only a small gap which the onboard error correction can handle.

Interestingly the DVD player has a 10 hour battery and a Pi-shaped hole

Wonder why they didn't add a software (aka SDR) chip, they aren't that expensive.
Or even an onboard padstrip where you can customise your Pi without compromising the
structural integrity.

-A

Ash Small

Sat Sept 22 2012, 01:10PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Conundrum wrote ...

Wonder why they didn't add a software (aka SDR) chip, they aren't that expensive.
Or even an onboard padstrip where you can customise your Pi without compromising the
structural integrity.

Lack of space. The RAM is mounted on top of the CPU. It's designed to be used with USB memory sticks.

Steve Conner

Sun Sept 23 2012, 06:25AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Re SDR: Doesn't one of the RPi media centre builds support USB TV tuner sticks? Gnuradio allows those to be used as general purpose SDRs.

Eye signal data: Wtf? Are you trying to hook up the RPi to the DVD player's screen?

Shrad

Sun Sept 23 2012, 09:03AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

I've been deceived by the Pi as for now, as it is quite slow and hangs up as soon as you do apt-cache search

Conundrum

Thu Sept 27 2012, 05:10PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Hmm, maybe you got a bad one? I have noticed mine gets pretty warm, sounds like a heatsink would be a good idea.
I would also try the Arch Linux as this seems to be better.
PM me and I'll send you an SD card.

Re. eye data. Yeah.
The problem is that there are few small screens for under Â£100, the best I can find is from a portable DVD.
It needs to be HDMI y'see, which most cheap surplus panels aren't.

Does anyone have a 24Cxx e2prom, LM1881, broken regular DVD player which goes "No Disk", a Pi and some free time and can see if this works?
I might be able to use a PIC 12F683 as a converter as to convert between two digital signals is a lot easier than D-A or A-D.

-A

Linas

Wed Oct 10 2012, 09:48PM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

not exactly same grade, but close...

Ash Small

Fri Oct 19 2012, 12:25PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I thought I might as well post this here, I'm after some feedback regarding ,for example, writing an android app, or whatever, so you can connect a smartphone to a Pi via usb, then use the smartphone as a keyboard, screen, etc.

Would this be feasible?

Shrad

Fri Oct 19 2012, 12:42PM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

most screens I have are XGA 7" ones with either serial commands to display primitives, or VGA input, so I believe the easiest to do would use serial mode for console, or a DVI to VGA adapter

I once saw cheap LCD + controllers from a chinese vendo who had controllers compatible with most vendor screens like toshiba, dell, samsung, etc... generic panes, and he had converters up to 1900*xxxx resolution

Martin

Mon Jan 14 2013, 11:13AM

Registered Member #9293 Joined: Sat Jan 05 2013, 07:08PM
Location: Worcester, UK
Posts: 3

hi Everybody,
Complete n00bie to this forum , but most glad I came across it

I have 2 Rpi in the house, one is primarily a house monitoring device recording router statistics, weather info ( wc 2300 ) and filesystem sizes, and my secondary pi is my playpi which I regularly break and build.

I've wanted to build a coilgun using the GPIO ports as a trigger for some time. I've already set up the simplest breadboard with 8 BC547 transistors triggering a timed sequence of LEDs and I want to replace the LEDs with coils. My problem is that I am very skilled in programming/computing , partially skilled in electronics, and not very skilled at all in making coiilguns so please forgive me for asking some simple q's at random moments

regards
Martin
*edit* oh yes, I've also build and figured out how to program one of the USB robotic arms that are out there - it would be fun to mount my coilgun on that

Conundrum

Mon Jan 14 2013, 06:48PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Hey Martin, and welcome to 4HV!

I've heard that a lot of people are using the RPi as a media centre, but making a "PiTV" and adding a very simple SD switch based on a 4066/4016 IC could increase its usefulness manyfold.

A lot of perfectly good small LCD TVs get trashed here because the power supplies or inverters grow BadCaps (tm) and with a simple repair can often be used as a 12V TV.

Can you post pictures of your setup please? thanks

kind regards, -Andre

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