It’s been quite a long while since I’ve posted anything, so I just wanted to put something up to reaffirm that I’m still here
It has been a busy few weeks for me in the world outside my workbench, so progress has been slow on the active projects. Here’s an overview of what’s going on:
- Macbook “full-featured” controller board: Boards hare arrived, waiting on component delivery (due Thursday). This will include demos of some new and lower-cost components which will eventually make their way into other boards.
- iPad “full-featured” controller board: On hold pending redesign for cost reduction and results of Macbook hardware evaluation (as much of the hardware is shared). Will leapfrog the Macbook and iPad boards until I am satisfied with how they work. Also am working on the software for this board. I’m really trying to get a USB firmware update utility built, but I’m new to the Kinetis platform so I’m having some trouble. Has anyone out there built a DFU loader for a KL25 that can share some pointers?
- Macbook camera board: I ordered a 2-layer version (inner layers are all GND) some weeks ago to test, and that worked fine. Now the proper 4-layer boards are in and I need to build one of those up. But I’m satisfied with the design in general so I should be releasing those documents as soon as I get the ambition.
- iPad touch panel: Oof… haven’t touched that one for a while. Need more free time…
- Reflow oven: I found some proper convection-type ovens at the local Wal-Mart for around $40 which will save me plenty of work in installing my own stir fan, so I may well be starting over. For now I’m getting too comfortable running the boards freehand with a temperature probe though…
- LP173WF2: Working on an interface board to take advantage of the connector hack I implemented. In progress, no ETA
So that’s that. Not much to show at the moment. But hopefully that’ll change this weekend when I get some work done on the Macbook boards.
Plus! I just this weekend got my new milling machine up and running! So expect some metalworking projects to start showing up from time to time.
That’s all for now.
[EDIT 9/9/13] Hey, progress!
Good ol’ 2880×1800 Futurama.
The Macbook board mostly works! Backlight driver is putting out on the low side of its designed voltage and the firmware is only complete enough to force everything on, but other than that, it seems to run pretty OK. Full post on this hopefully tomorrow.
A short and sweet update for today. I have built up one each of both iPad interface boards, and am having DP link failure issues with both. I am beginning to suspect that something may be wrong with my connector pinouts. I have pulled the documents until I can iron everything out. My apologies if anyone has already ordered these boards and they end up being incorrect.
I’ll post an update as soon as I figure out what’s going on.
[Edit] Damn it all. I numbered the DisplayPort connector pins in the manner of the source-side connector instead of the sink-side. On the sink side the ordering of the lanes is reversed (3,2,1,0 instead of 0,1,2,3). So all the DP lane pins are wrong on both of my boards. Super apologies to anyone who ordered these boards, and I’ll have them fixed in a short time.
[Second edit] I’ve also got a plan for how to salvage these boards if you were unfortunate enough to have ordered them. More on that later.
I haven’t got the ambition to do a full post today, but here’s the state of the world:
Full Interface Board
After the longest 15 days ever, this board is finally at the fabricator. It is missing the USB crystal and I have changed the pinout of the button and LED board connector, but this revision is what it is and will at least be good for troubleshooting. Parts are mostly on order.
These boards finally arrived, and what do you know, they’re just too small to use comfortably. I have redone the board, replacing the switches for larger ones and the LED for a slightly larger common-anode unit to trim cost and aid availability. The new board is 60% taller and the exposed area is slightly wider to accommodate the larger switches, but the board area is fairly comparable so the cost is similar. I will write a full post and release the documents on the new board sometime soon.
Simple interface board
Also has made it to the fabricator. Parts are also on order. This is likely to be the first board that gets built, as it will allow me to test out the panel. Keep an eye out.
Reflow oven mod
I have installed the insulation and the air exit port. The insulation makes a dramatic difference in the speed at which the chamber heats and cools (it heats to 260C a full minute ahead of the noninsulated chamber, and cools much more slowly). I am still contemplating how to install the air intakes and diffusers, so that’s the major mechanical holdup at this point. Electrically, I am awaiting parts in order to model them for PCB footprints, but at least some of what I’ll need (such as the enclosure) are on order. SSR is in house now, as are the thermocouples; thermocouple interface ICs are on order.
iPad touchscreen breakout
Boards are at the fabricator, parts are on order. Should be in on Monday. Maybe these will be the first ones to be built up. Research progress on the digitizer is halted pending the build of the boards.
Sure seems like I have a lot of things going on right now, mostly waiting on fabricators. I could use a faster board house than OSH Park… but it’s hard to beat the price. How can anyone be making money when I get three boards shipped to my house for $2.50?
I don’t have enough content for a full post today, but here’s the state of things.
Full Interface Board
I discovered that I made a dumb mistake and left out the oscillator for the USB controller in the MCU. The oscillator takes a good amount of floor space and the board is already packed, so a fairly serious redesign of that section of the board might be in order. Thankfully I’m only out $40 and not the $couple hundred I would be at a traditional board house. I’ll still use the existing boards to work out the kinks on the power switching and backlight sections and to develop the non-USB functions of the MCU. Actually, so long as you aren’t using USB, the boards should still be perfectly workable. Nonetheless, documents will be held back until this is resolved.
Probably too small, but I want to see how too small before I remake it. Boards on order. Documents released, but you probably don’t want them yet.
Simple interface board
Out for manufacture, documents released. Go nuts, but do realize that I haven’t tested this design in the slightest yet.
There is also a new project on the horizon which will get its own post as soon as I can talk enough about it to do so. It will be impossible to hand-solder these boards what with my love of QFN and related no-leaded parts and things with thermal slugs. The company where I work has a nice 6-stage production-class IR reflow oven, but I’d rather not have to ask them to fire the thing up to do one tiny board. For a few years now I’ve been contemplating building a desktop reflow oven for my personal projects, and this seems like it might be the perfect opportunity. I have been gathering materials for a while and now am at a stage to put a design. Keep an eye out for that in the coming days.