{"id":1311,"date":"2018-06-25T14:58:03","date_gmt":"2018-06-25T13:58:03","guid":{"rendered":"https:\/\/ofalcao.pt\/blog\/?p=1311"},"modified":"2018-06-25T15:12:24","modified_gmt":"2018-06-25T14:12:24","slug":"rock-concert-iot","status":"publish","type":"post","link":"https:\/\/ofalcao.pt\/blog\/2018\/rock-concert-iot","title":{"rendered":"Rock Concert IoT"},"content":{"rendered":"
This post is part 5 of 5 of \u00a0LEGO Rock Concert<\/a><\/div>

So last days I’ve been assembling the stage surroundings, a truss-based structure to support the left and right video walls and also the self-powered speakers:<\/p>\n

LEGO Rock Concert: good progress with the stage and electronics<\/figcaption><\/figure>\n

I gave up hiding the speakers under\/inside the stage. I know, speakers aren’t LEGO but I think they look good enough this way.<\/p>\n

Also I have been testing the Raspberry Pi Zero W with the PiTFT and a local USB webcam. I use ‘VLC’ to stream the webcam video to the wireless network and can show a stream on the PiTFT with ‘mplayer’. And since mosquitto-clients package is also available for Raspbian I got a way to control everything with just a bash script with MQTT.<\/p>\n

So this is the IoT setup now:<\/p>\n

LEGO Rock Concert: The IoT<\/figcaption><\/figure>\n

From any mosquitto publisher I can select which stream to show on each video wall and also start a bash script on the EV3 with the sound card and the LEGO Power Function lights so a music plays while the lights blink.<\/p>\n

Only problems till now:<\/p>\n

    \n
  • ‘mplayer’ takes 5 seconds to start playing the stream, doesn’t seem to be a problem with the raspberry nor with the stream, just some kind of warm-up from mplayer, if I can’t fix it will have to find another video player that works with the PiTFT (it’s framebuffer, not X-based)<\/li>\n
  • a small USB endoscope camera I was considering using has some problems to show up on first boot of the Rasberry Pi so I will probably use another webcam, bigger but more reliable<\/li>\n<\/ul>\n

    While testing the IoT I used my Ubuntu laptop (‘mosquitto-pub’ and ‘mosquitto-sub’) but found a MQTT Dashboard App that works fine both on my Android 5.0 Phone and my Android 4.0 tablet. But I also wanted to use an EV3 as a controller so I tested a few bash scripts with the local keys but found it too limited… so decided to make a better control panel:<\/p>\n

    LEGO IoT Control Panel<\/figcaption><\/figure>\n

    The four medium motors are used as selectors,\u00a0 I divided a whole rotation in 8 intervals (45\u00ba each) to have 8 options on each motor. So it works like this:<\/p>\n

    – one selector for Video Wall #1<\/p>\n

    – one selector for Video Wall #2<\/p>\n

    – one selector for Sound and Lights<\/p>\n

    – one selector for Special Effects<\/p>\n

    I can choose what stream I want to show on each video wall and start playing a music. Later I will add more options (photo presentation, youtube video…) and use the 4 EV3 touch sensors to adjust parameters for each option (like the brightness, the frequency or the effect of the lights, the volume of the sound, forward\/backward while showing some presentation…).<\/p>\n

    A video explaining this:<\/p>\n