More work on case design. Venting is a must. With all pixels lit, this thing makes a fair bit of heat. I think it might also need a thermal cutoff, just to be safe.
Edit: Files off to be cut. With some luck, they’ll be here in time for the long weekend.
Latest greatest hardware for Hearth mates directly to the first LED module in the chain, minimizing external components and assembly hassle.
The board can be populated in two different configurations: 1) Infrared remote control, relay for remote power control or 2) Bluetooth control (smart phone, tablet, etc..). The board pictured is populated for Bluetooth control.
Printed circuit board lessons learned this time around:
- Quadruple check the files before they go out! I spent a bunch of money and waited a few weeks for a set of completely incorrect boards. Fortunately we were able to salvage one and bodge together a Hearth dev kit for Ishani.
- Don’t use a copper flood if you don’t need one. The soldermask on this batch of boards was a little offset, resulting in some places where it’s easy to bridge a pad to ground unintentionally. In the next rev, the ground plane will be limited to the back side of the board.
- Place footprints for bigger e-caps than you think you need.
- Make sure the board house will use a milling layer if you use one. Mine doesn’t. Consequently, there are some oblong holes that came out small and round. In the next rev, the milling layer will be replaced with stacked drill hits.
Simplified Hearth case design. Faceplate and sides are a single welded unit. LED modules mount directly to the back plate with threaded spacers. Redesigned electronics mate directly with the first panel in the chain. Power, USB and infrared connections exposed through the back panel.
Ishani informs me that yesterday was Worldwide Pinhole Photography Day. Here’s a shot from his brand-new Hearth devkit we assembled in the afternoon.
Prototype standalone board for the fireplace is off for fabrication.
…because sometimes it’s OK to give yourself a pat on the back.
Our pick of the show was the Oddity boxes by software engineers, John Popadic and Harry Denholm mainly because they were so damn cute. These adorable and tiny cubes produced a series of low res visuals that made us want one immediately.
..and finally John Popadic and Harry Denholm combine their talents to build Oddity, a small box of light that allows the user to select a graphics algorithm and play with its inputs to vary the output within a predefined program. Oddity is also a toolkit that comes complete with software that can be altered to produce custom effects using your own imagination.
The original Oddity has some issues with flaky rotary encoders. The encoders are mechanical switches, which don’t generate clean transitions. There are variety of ways to deal with this in software, but all of them take time. I’ve chosen to sacrifice a tiny bit of board space and implement full hardware debounce straight from the Bourns app note to make Oddity revision 2’s controls as silky-smooth as its graphic output.
Hearth revision 2 is well under way. Breadboard prototype using the bare ARM chip is running on my workbench. We need to make some decisions about what kinds of inputs to support (currently Hearth has an infrared remote control) then then it’s time for a new board revision. Toying with the idea of a Bluetooth connection after browsing the Pixeled project. It’s probably worth adding the standard rotary encoders as well.
The original Hearth prototype has been fitted with a little infrared remote control and is now swirling away in my unused fireplace at home. It’s now running the full Oddity code so, with the push of a few buttons on the remote, we can change effects and effect parameters from the comfort of the couch! Once I get a relay hooked up to the remote, so we can power the thing down without getting up, it’ll be ready for an “official” board revision and reproduction in small quantities. I’ve got a few encouraging quotes back on the acrylic fabrication, which means it may become more time/cost effective to make.
Odditiy has been stripped down to parts and is undergoing a serious hardware revision. The core functionality of the object won’t be changing, but all the parts will end up on a single board, which should make it easier and cheaper to put together. I’m still trying to re-imagine the case such that it can be done without expensive laser cutting and complicated welds. I’m still proud of the original design (electronics on a little sled that slides into the main case, secured by a nylon screw) but I’m sure there is a simpler workable design that could be made by a specialist acrylic fabricator.
Stay tuned for some video of Hearth running some slick Oddity effects as well as progress on the Oddity redesign.
Hearth flickering away in my fireplace at home.