Marc's Public Blog - Electronics Hacking


vvv Click on the categories below to see other topic specific pages vvv



Table of Content for electronics:

More pages: January 2025 November 2024 September 2023 August 2023 June 2023 May 2023 April 2023 January 2023 November 2022 January 2022 May 2020 January 2020 December 2019 April 2019 January 2019 June 2018 May 2018 June 2017 April 2017 May 2016 February 2016 November 2015 October 2015 August 2011 July 2011 May 2011 June 2010



2025/01/18 Extended Festival LED Shoes Version 4
π 2025-01-18 01:01 in Clubbing, Electronics
So, you would think that as part of my complicated LED outfit that was several years of work over the years including over 10,000 lines of code, the shoes would not be a big deal...
Well, after having gone through more than 10 different pairs of LED shoes that all failed in various ways, I have to say that these were more trouble than expected.

Issues:

  • the early ones had wires or PCB between the pixels that would break after the shoe was bent many times as part of walking/dancing
  • later ones fixed this, but still used the same small module with limited battery life, barely good enough for 4H
  • even unmodified, the LED module resin would eventually crack, and usually the battery fail
  • worst failure was a lipo that did fail in a way that it smoked/burnt, not great under your feet (thankfully this was contained and my foot was ok)
  • the only way to add battery life was to solder a connector to the lipo pins inside the module, which is a bit tricky (getting a good sodler joint) and not getting that connection to fail later, which with dancing does happen too often* then, my first design which included adding a 2nd battery inside the shoe, turned out to be a mistake as the 2nd battery was not protected well and would eventually be breached. Also the thin wires for the orignal batteries I used woudl also fail:
  • I had to melt the resin until I could expose the power pins
    I had to melt the resin until I could expose the power pins

    looked ok on the bench, did not work long in the shoe
    looked ok on the bench, did not work long in the shoe

    shoving the battery in was not easy
    shoving the battery in was not easy

    it worked on the bench, but didn't work too long in real life, by then I added an external lipo plug to check the voltage and do fast charge, bypassing USB
    it worked on the bench, but didn't work too long in real life, by then I added an external lipo plug to check the voltage and do fast charge, bypassing USB

    By then, I had what I thought was a great idea: why don't I just forget about secondary batteries and use the external connector to power my shoes from my pants that already have 5V power on the neopixels?
    This felt like a good idea, but first I had to add diodes to drop 0.7V so as not to exceed 4.3V for a direct connection to the lipo (as a remminder, I cannot connect via the USB plug as if you send power there, the shoe does in charging mode and stops lighting up), but then I found out that my neopixel strips did not actually have 5V at the end due to line loss, and it was going to be complex to safely connect them to my shoes without a voltage regulator and more electronics, making the whole thing, questionable. Still, it was a tempting idea for a short while to use my mega battery pack to power the shoes forever ;)

    So for version 4, I had slightly better connection of the external lipo connection with hot glue around the module, but the more important part is I figured out it was better to attach a flat lipo on top of the shoe so it wouldn't get stepped on:


    I also had spare modules and batteries in case of failure, and a way to charge them from USB outside the shoe:


    By then I had run out of my old modules that slowly failed over time, and had to find a new shoe with compatible modules. Thankfully that one has slightly better firmware that allowed lighting one LED out of two:



    at least it's pretty

    A big thanks to IGxx for nicely sending me extra modules so I could hack on them and have spares. Here is the shoe I recommend you buy today: https://www.amazon.com/gp/product/B07GS6GSRY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

    This is the new shoe with the updated module. Very pretty shoe, but otherwise the modules still have the same 4h runtime, and still need the same work, bummer:



    battery goes up there so it's not stepped on
    battery goes up there so it's not stepped on

    So yeah, we're now at v4, it still relies on unreliable soldering, and extra hot glue but at least the external wires are stronger, the external battery more than long enough for 12H+ of runtime

    2025/01/17 House Lights with Pixelblaze on ESP32 monitored with Raspberry Pi
    π 2025-01-17 01:01 in Arduino, Electronics, Linuxha

    got a few extra colorful yard lights ;)
    got a few extra colorful yard lights ;)

    To debug some early issues I had with the pixelblaze, I soldered a few extra wires to add serial monitoring:


    the serial port is temporarily going to a rPi3a which in turn makes it available over an ssh connection
    the serial port is temporarily going to a rPi3a which in turn makes it available over an ssh connection

    up left if the pixelblaze pro expansion board that gives 8 channels, handles power distribution and converts the 12V to 5V for the pixelblaze itself
    up left if the pixelblaze pro expansion board that gives 8 channels, handles power distribution and converts the 12V to 5V for the pixelblaze itself

    For the pixels, I picked rolls of 1000 pixels at 5cm and 10cm pitch from Ray Wu, trusted seller of blinky stuff, and one bonus of not doing this installation a few years earlier is that new pixels have been designed: WS2818.

  • WS2813 were a improvement for having a backup data line but still running on 5V which would have clear voltage drop issues.
  • WS2815 are the 12V version, which is good for dealing with voltage drop
  • WS2818 is yet another improvement over WS2815, still 12V with a backup data line, but more reliable and efficient
  • The last bit "more efficient" actually worked to my advantage as I was able to make a string with 600 pixels and not have to re-inject power anywhere. I measured line voltage at the end and it was only 5V but the pixels still worked great at the reduced voltage.

    The advice I got on the leds are awesome group was to try hot glue, and it was a good idea. Thankfully I had a battery powered hot glue gun, which was a must have. The other important bit was a solder reflow hot air gun, which did have to be plugged in the few times I had to unglue strips to move them after I found a better routing or visual pattern:


    And in all, I actually need 3 tools, the 3rd one was a battery operated air can replacement which allowed me to blow cold air on the hot glue points and have them dry in 10 to 15 seconds instead of 1mn. That was a lifesaver:


    After laying strips, house looked like this:



    After the first 2 days of work, I had 4 strips, around 1500 LEDs:

    or on youtube:

    But it really got better once I added 2 more strips and upp'ed the count to 2000, which was a lot more visually pleasing:

    or on youtube:


    More pages: January 2025 November 2024 September 2023 August 2023 June 2023 May 2023 April 2023 January 2023 November 2022 January 2022 May 2020 January 2020 December 2019 April 2019 January 2019 June 2018 May 2018 June 2017 April 2017 May 2016 February 2016 November 2015 October 2015 August 2011 July 2011 May 2011 June 2010

    Contact Email