Blinkenschild 2.0

So you want to add TWITTER to a project?

Thats nice and all, but you know.. twitter changed its APIs significantly in august and with those changes came new conditions.

If you want to develop something with twitter you need to sign up for a developer account.

Fair enough right?
Its easy peasy, no worries.

Just fill out the three pages of information regarding you, your project, and its purpose, where, how and by whom it will be used in which country and the project description must be at least 300 characters.

You consider this ironic given the limit of the message size on tweets? I sure did.

Twitter will get back to you via email some days later letting you know that you will need to provide further information.

Once you sent an in-detail description of your project they will contact you.

Oh they didn't? 
Too bad, you will have to ask for permission to use the precious APIs again, i guess.

After over a week of waiting twitter finally sent me their oAuth API credentials and i implemented the twitter import in an hour.

But this procedure gave me goosebumps. Especially that they referred to "their content from twitter" that i would use in my product. 

I will have to implement mastodon as well i guess.

I finished the backpack mount today.
I use a kids backback that has a fixed aluminum frame and mount my custom construction on this with zip-ties.

It feels very good to carry that sign with this construction. I can totally imagine walking some hours at a demonstration with this setup.

I carried my kids on austrian mountains before, using this backpack, so i know that it wont hurt my back :)

The batterypack lasts at leat 5 hours with connected WIFI and twitter updates.

We will see about the overall performance in some days..

The Blinkenschild 2.0 is powered by portable battery packs.

Today 4 strong battery packs arrived in the mail.

I had some leftover usb connectors form another project that i soldered into POWER cables.

Each 16x32 panel has its own usb attached power supply and the GROUND rail was connected on all boards.

I also have a dedicated batterypack for the Raspberry Pi.

So far so good.

The twitterscript is running for one hour so far, the leds are bright and the whole setup appears to be stable enough.
The only thing that worries me a little is the Raspberry Pi that complained with an undervoltage warning earlier.

I might connect a second usb cable and merge those for the power supply.

The cabling went better that expected.

I used zip-ties and shrinkwrap on the cables, the picture looks much messier than the real life outcome :)

I made a GIF player :) 
Look at all the colors!

I started Twitter integration today.

The Idea is to have  a webinterface on the Raspberry Pi.
The Pi is connected over wifi to your  smartphone and has internetaccess trough Thetering.

Now users can send tweets to @blinkenschild and those are displayed in realtime on the webapp / Smartphone.
If the carrierof the Blinkenschilds want to show the tweet, it just needs to be selected from the list and is given to a service on the Raspberry that displays it in scrolling text as shown above.

The webinterface is not even started yet, but we do have the command line tool ready to display the actual tweet. 

The Hardware assembly is finally finished.

We had to replace one broken panel, but all in all it worked out as planned.
Also the Fixture for the aluminum rods was mounted upside down, so we had to move those.

hzellers software to drive those HUB75s from the raspberry pi is gorgeous!

We will have to send him cookies.

So far we got:

• Youtube video support
• Scrolling Text
• Images
• GIF Animations

Next we will add Twitter support and a nice Webinterface to interact with the sign.
Also we need to get some USB Powerbanks to make that sign portable.
And of course we need to make a cover to make that thing weatherproof and portable.

We use the great library by hzeller to drive the HUB75 panels.
Check it out here:  https://github.com/hzeller/rpi-rgb-led-matrix

After wiring the Panels and soldering the levelshifter adapter board the thing was up and displaying demos in no time.
Henner did a GREAT job at providing examples and useful tools like

•  a modded ffmpeg player 
•  a scrolltext display 
• a framebuffer proxy
• a generic picture viewer 
• and good examples on how the C API works

We will probably stick to using his tools and (just) make a webinterface for uploading and selecting animations.

On the raspian side we had to disable the soundcard and select a dedicated cpu for the display controller.
How this is done is also very well documented at hzellers github.

Challenges:

Getting the drivers running was a piece of cake, but now we need to make the webserver and webapp.
This will be some work.

Once we finish this, we will set the raspberry pi in a READONLY state so we can safely unplug it without damaging the FS.

All animations should be stored on an external USB stick and not on the SD card itself. 

When I built the original BLINKENSCHILD some years ago I wanted to give a useful tool to protesters.
Now some time passed and the reasons to protest are at an all time high.

When Max asked to borrow the original Blinkenschild, I decided the time was right to build a more up-to-date version with higher resolution, a lower price tag and modern technology so we can play back videos and do some interesting internet enabled stuff.