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I posted a Status Update yesterday stating I had put up some festive lights and genebren asked if I had any photos: so I've just been outside and video'd you can see I'm not very good with a camera and focusing in the dark on these varring brightness objects was a bit tricky. Hopefully you can see the effect though. They are also nothing like some of the festive lighting spectaculars on Youtube including those of Tom GetGeorge



WS2811 LED Fireworks

These are not new, I made and added to them over the last few years although I had to do some repairs and re-programming this year. The video starts with my LED fireworks. I made these using individual WS2811 RGB LEDs and soldered each together. They are mounted to arms (old fibreglass tent poles) and each arm is paralleled up. The effect is free running, controlled by a PIC16F1509 microcontroller and incorporates some randomness of delay and which pattern is selected. I actually wrote all that code in assembly language before I decided to move to the Microchip XC8 compiler. The rate of change after initial 'explosion' slows to create an effect of the particles being ejected and they also dim slightly in intensity as they move out. Note to anyone wanting to copy this: it is very tedious work, cutting those sections of wire, tinning them, soldering each in the jig. And in an unheated shed during winter it was very cold.

The centre hub of each firework was made using disks of marine plywood, drilled, the rods glued in place and the surrounding areas filleted with car body filler. This must be the third year now and they have deteriorated somewhat with the wet/heat/rocking in the wind. I gave them some temporary repair with more epoxy but need to rebuild those hubs out of plastic or metal rather than wood.

Centre Hub - Damaged

The electronics is housed in a 25mm deep surface mounting electrical box (on the far side of the photo), suitably sealed with clear silicone and painted black.


I topped each WS2811 with an 'Iced Gem' of silicone sealant to act as a diffuser - and they work really well, although not as tasty as the actual treats.


Starburst Effect

There are three firework effect LEDs that I made but you may also notice a plain white effect which looks like I'm making the jump to lightspeed. This effect is a bit of a cheat but seems to work really well. It is based on 16x tubes that hang down and make a Meteor Shower effect...that is what they are sold as. However the oscillators are setup to allow them to drift, mounting the tubes radially gives an interesting effect but less so in daylight as you can see the old bicycle wheel that I used to mount them on !


Strings on House / Tree

The end of the video shows a string in the potted plant and on the eaves. They are WS2811 strings on the eaves are pre-wired and the ones in the plant are individually made using WS2811 die and hot melt glue to seal and add the diffuser. I'm running them off separate PIC18857 microconrollers (this device also has a CLC peripheral to set the WS2811 timing whilst the PIC can decide what to output next) and the code is written in C using the XC8 compiler. I used the basis of this for myPIC Microchip LED Effects: Firefly Part 1 back in the summer - so when I dug the lights out I had to re-program them with these nice patterns.


Other Past Setups

Last year I used a Raspberry Pi to control the lights from Vixen3 sequencing software. It worked really well inside the house, for a while outside, WiFi became intermittent before I finally damaged one of the boards out in the dark. I made some notes about that last year in this article

I would like to get that system up and running again, perhaps just for the eaves lights, as it was cool to be able to adjust the pattern from my PC. I also have some more parts on order to make a couple of other free-running firework effects to add to those in my short video.


What Can Go Wrong

Even though I was really careful sealing the individual LED chips moisture seems to get in and has managed to affect some of the lights. This might appear as a stuck pixel or part of an arm no illuminating. Luckily it only happens after a few weeks of being outside. Taking the faulty decoration down and drying it slowly indoors seems to restore functionality for a few more weeks. I'm also amazed how much a thick pine tree sways - especially when I'm up there and a squall blows through (I'm sure that happened last year as well)


I'll try and add some more detail or updates when I expand my display.




[ updated 12 Jan 2019: further build details can be found here LED Firework Suite - the details ]