[sigplus] Critical error: Image gallery folder photos/2011-marlinespikes is expected to be a path relative to the image base folder specified in the back-end.

concept: 3d print a dumpster, put LEDs in there to simulate fire. Bonus points: internet & use current events to drive intensity.


  • https://www.thingiverse.com/thing:950602
  • print all parts at 140% scale
  • compensate -0.02mm "bin"
  • use green PLA (Matter Fiber HTPLA is great) for bin, hinge, sleeves
  • use black TPU for wheels & lids
  • use piano wire for "bar" (hinge pin); bend one side

Tea lights:


  • Particle Photon (fave IOT platform)
  • APA102 or WS2811, high density, 10 LEDs
  • 128x64 OLED display for stats

The intensity feed:

  • IFTTT: if "user posts on twitter" then "publish an event to Particle". It's a public event, the data is entirely the contents of the tweet. The device subscribes to / receives that event and uses the number of characters to drive the intensity. Over time the fire dies down to a relatively low smolder.
  • In the video below, the unit starts at minimum intensity and reacts as if to a 45-character tweet. Over the next ~48 minutes the intensity will die back to the lowest value (unless there's more tweeting).

(notes to future self)

HTPLA from Proto-Pasta is reallllyyyy good in the kiln. Other PLA (lookin at you, Jessie) kinda sucks.

200F / 2h: no warping, good result

210F / 2h: warped, layer separation

205F / 2h: warped (but not as bad as 210)

200F / 2h: wood PLA + HTPLA, minor warping in wood (barely noticeable), no separation


Remove the cover to expose the "guts". There are two buttons near the USB jack labeled "SETUP" and "RESET". Press and hold SETUP for about 3 seconds; the LED by the buttons will start blinking blue.

On your phone: turn on airplane mode, enable WiFi, and look for a network like "Photon-######" (mix of numbers and letters, unique for each permalite). Connect to that network. Open your phone browser and navigate to

Select the correct WiFi network, enter the password, and save.

Press (and release) the RESET button. The device will reboot and should show a pattern on the small LED starting with blinking green, then ending with a "breathing" Cyan / light blue. The main LED display will begin after a few seconds.


New idea: permanent christmas lights. I read about this on a company "makers" mailing list, no credit to the author (it's been some time, lazy, etc). The idea is simple: use programmable LED strips, mount them (permanently) outdoors, and update them for the seasons.

The LED strips are the easiest part. Amazon sells them in 5m reels (like this), and they can be daisy-chained for arbitrarily-long strips. The LEDs are spaced out, depending on what you want. For side-of-house application, the least-dense option might work well -- 30 LEDs/m, or ~150 LEDs in a 5m segment. That costs like $20 ish. By math they probably consume about 10A per 5m (60mA per LED * 150 LEDs -> 9A, plus various loss along the way. Each strip can have it's own injected power... The linked ones include a waterproof enclosure. One could also feed them into (say) translucent PEX tubing and skip the silicone jacket.

For an MCU platform, I like the Particle Photon (or its kin). Easy stack over wifi (no USB cable) and the "cloud" interface is nice. With minimal programming I can have a web interface to change features like speed, brightness, pattern, etc.

The physical device will be straightforward: a plastic box, maybe 1-2 buttons, a terminal for the 10A power input, and a plug / dongle to tie into the first LED strip. Probably a CdS sensor (light sensor) to adjust brightness, turn off at dawn, etc.

I prototyped the first setup on a breadboard. The LED strips use 5A power which I can pull directly for the MCU, and the MCU drives 3.3v signal which also works great for the LEDs. FastLED library, of course. A simple button (PULLUP + ground) for "change the pattern" (short press) or "change the speed" (long press). CdS is a 10k resistor + the sensor itself, NBD. I made a generic protoboard and they're on order from OSHPark, who are thankfully still open during CORONAPOCALYPSE.

The generic protoboard will do just fine for such a simple project. It has a terminal input for any power level (5-30v), and onboard solder points tied directly. Solder up the 5v pigtail and use the terminal for power supply input. All data pins are broken out in two positions; use D0 for the pigtail data line. Button is easy (mount to a case, one leg to a data pin, one to a GND pin). CdS is almost-as-easy: 10k resistor in the middle line between GND and an analog pin, CdS between 3v3 and the same analog pin on an outside row. Expose that to the side of the case for light entry.

The two components are a medium-sized cap (like 2-10 uF) and an LP2950 regulator.

TODO: get the boards, design + print an enclosure.

Animations are really the easiest part of all this. Once the hardware is done one could update the animations via WiFi... For the time being I've really got one class of animation: seasonal colors, moving slowly. When I'm sitting right in front of it I can't tell it's moving, but if I look up every 2-5 minutes it will have completely changed. That's driving in a simple function which uses a seasonal pallet of 4 colors: red-white-blue-white for independence day, green-red-green-red for xmas, orange-black-orange-black for tgiving/halloween, etc. I like these because they're both dynamic and subtle.

Also considering "chasers" or some active animation, but I don't want them to be too annoying to my neighbors, most of whom I like.

If you start sintering a bunch of crap, or otherwise start running a kiln a lot, you may wish to know what the *actual* interior temperatures look like.

I rigged up a thermocouple on a Particle Photon, to independently measure and record temperatures. The kiln has an independent digital display based on its own thermocouple, but I can't record those values beyond pen/paper (which is obviously tedious)... and I'd still want some way to independently verify the internal temperatures.

Having an external thermocouple also lets me bury it in refractory to get some sense for heat penetration and transfer delays.

There are a few common ways to age or force "natural" patina onto bronze and copper alloys.

  • Bright green verdigris: copper carbonate
  • Dark green verdigris: copper II acetate
  • Dark brown or black shading: ?? (some sort of copper sulfide?)

The verdigris can form spontaneously just from cleaning, and will "stick" best to very clean (polished) bronze. They can be prevented with light waxing, and can wipe off with a soft cloth.

The darker color, as an "oil-rubbed bronze" finish, is an integral part of the surface material and can only be removed with aggressive wire brushing, sanding, or other surface removal.

skulls with various finishes

Note: this is an addendum to the 3rd step of a print / sinter / polish process.

Solid bronze can be finished and polished to a bright luster, not unlike jewelry. It's a very hard, beautiful metal with some cool properties. It cleans up similar to metal-filled plastics, but there are a few steps specific to solid metals.

tl;dr: pickle, brush, shape, tumble, maybe brush again, polish, buff, wax.