Category Archives: Raspberry Pi

mosquitto connection refused

Hi all, if you’ve just upgraded mosquitto server on some flavour of linux and wondered why all your mosquitto subscribers and publishers on your network have just started failing, you may have fallen foul of this:

the new mosquitto 2.0 requires a ‘listener’ be configured to the ports required, or else it will only listen to the localhost:1883.

So if all your clients start failing after, edit the configuation and add the following line to the top:

“listener 1883”

See the post here for more information:

Local Weather forecasting

Just a quick note to enquicken someone else’s google seaches in the future,

For local weather forecasting based on ambient air pressure, the algorithm you need is the Zambretti algorithm .

The original Hackaday article on this is here:

And some useful matlab code to get you started is here:

Finally, some tags to help google air pressure wheel forecast ambient air pressure bmp280 bmp180 air pressure forecast etc.

Office music

isolation with headphones

or Togetherness by synchronised streaming?


Apps used: 

  • Logitech media server (aka squeezebox) – running on a  Raspberry Pi
  • Squeezer (Android) for remote control, queuing tracks, playlist management and synchronising the players
  • SB player (Android) to play the 

    Ps, it’s way past my bedtime! Insomnia is a pain. Goodnight all. 

    [UPDATED] G Projects

    My friends Pi, after repairs to the sd card holder.

    [purple means updated on Sunday Feb 2nd 2014]

    My pi in its latest incarnation:

    The other day a good friend and fellow geek of mine acquaintance was reminding me that it’s not possible to do everything we want to do, and actually harmful to try and shoehorn everything in. Someone told him this, and he passed it along.

    It got me thinking (and googling – what doesn’t these days?)
    Are you a Perfectionist? Do you find yourself telling yourself this: ‘I can’t relax till i get it all done’?

    If so we are kindred spirits!

    Anyway, here’s all the projects that I’d like to complete:

    Raspberry Pi


    V2 of the User interface.

    • Prettify
      • Layout does not work in IE9. – Who cares?! No one likes IE9 anyway!
      • Embedd/add link to xively
        • Can we get image of all feeds on one graph?
        • Change layout to 4 column 3 row to add this?
          • enough space?
      • apply css to sockets page
      • get that annoying favicon to work! (maybe it doesn’t like the filetype?
        • save as gif/make it smaller and reupp/change mimetype
    • Test – new squeezeplayer page needs testing
    • Develop ?python? code to allow setting of Home Automation parameters
      • E.g. on/off times per DOW

    Pressure sensor:

    • Write Exponential moving average code to smooth the values. I found the code somewhere…refind and figure out
      how to store the data to be ema’d
      variable – can bash hold arrays?

      rrdtool – effort bruv
      use xively api to read old datapoints – ditto
    • Descriptive weather prediction – e.g. ‘rain coming’ [Just today it rained, so I have worked out the min time resolution needed to predict/try and deduce if it is raining]
    • Absolute Humidity calculations – output moisture density of air to see how much has been added(RH% is not a good measure of the amount of water bc it’s relative to temperature, and I want to find how wet the air is!)
    • Solder to Slice of Pi board

    i2c LCD Screen:

    • Connect to Pi on fly lead (attach to pibox?)
    • Output status – e.g. current sensor data
    • Output interpreted status – e.g. ‘it’s getting hot in here’, Nice weather coming etc
    • Implement a simple UI with pushbuttons ->gpio
      I actually designed the UI while in a meeting!
      functions like shutdown, remote power control, network configuration/join wifi,slimclient/server control?

    RFM12b 433mhz wireless transceiver module:

    • Connect to pi (on fly lead? bad reception has been problematic on the transceiver according to
    • Implement data decoding from CurrentCost transmitter
    • Control remote sockets ala home automation

    Streaming Music Server – Plug and play, wireless capable – Using Squeezebox/LogitechMediaServer

    Remit: To be able to rock up somewhere, plug in power, and then play music wirelessly from my collection
    (Extra: stream from the internet if connection available)

    • Stream music from Pi
    • Control Music from Nook using Squeezebox Android app
    • Stream music to my Hauppage MediaMVP (wirelessly [using WEP])


    • Got MediaMVP to boot from Pi when pi was using wired network
      • tftpd-hpa (modify to port 16869)
      • compiled mvprelay.c 
      • wrote init.d script for mvprelay to startup and point to ip address of pi
        • Need to find a way of dynamically setting ip
        • (altho when setup on wifi, up of pi will be statically fixed)
      • downloaded mvpmc image to boot on the MVP
      • wrote a dongle.bin.config file for the MVP to load it’s config at boot and start the squeezebox ‘mclient’
        • this should enable headless playback, so won’t need a tv screen for Video
      • made a dongle.bin.ver file using dd
      • booted it


    It wouldn’t boot over the network bridge. It talked to mvprelay using UDP; tftpd-hpa gave ‘ACK connection refused, could not read’ weird errors when it tried to download the files.
    My laptop however could suck the files up no problem. Weirdness!

    Todo: investigate settings on Bridge AP looking at what happens to BC packets. And also check DHCP relay settings.
    I think they might be flooding the network somewhat.

    1. Setup Pi hostapd: Configure the dhcpd config file
    2. Repair the wifi dongle: The usb socket is no longer solidly connected!! Need to dremmel the plastic off and resolder, then melt and reattach the plastic, (it’s meltable) but a lot tighter this time!
    3. Get the donle working ok in debian/raspbian. (haha, good luck)


    I can’t do it all………………….

    at least not all today!

    Actually, part of me likes it going slowly (certainly a surprise to the rest of me!). Time to mull things over, make decisions, come up with sketched designs and sometimes even pseudocode/real code.

    Seems to have it’s advantages not trying to do everything right now at least haha.

    On that note, bed time! [ 2:03 am this time]