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.
Button board
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?
Can’t wait to see the progress! Now that there’s a breakout board that doesn’t cost an ARM and a leg, maybe my wife will let me build an external monitor from this. Still have to get a displayport on my rig somehow… Are you going to be building a bezel?
I won’t say that it won’t be expensive… buying parts in low quantities makes things pretty pricey. The first person to bite the bullet and buy stuff for 1000 of this sort of thing will be the only one that can offer them cheap enough for the general public. The simple breakout won’t be bad at around $20 for board and all components, but there is no backlight driver onboard and you may not get voltage over DisplayPort so you need to source 19-20V and 3.3V from somewhere which is an additional expense. The one with all the bells and whistles will easily be over $50, probably by a lot (although I haven’t run a BOM cost yet so I’m not sure how much).
Somewhere along the line I think I’ll put some effort into a DVI interface board for this, for all the folks that have the same problem of no DisplayPorts… but that’s not going to be for a while.
I’d like to build a bezel, but I can’t think of a way to do it cleanly without some machining equipment. I’m good with a Dremel, but not good enough to cut a perfect rectangle that won’t bother me as I look at it all day. A mini-mill is on the shopping list for the next few months though, so that will help things along. In the meantime I plan to make a barebones stand out of thin aluminum bar stock, just complex enough to prop the thing up semi-vertical on the desk. That will tide me over until budget permits me to buy machinery. I’ll post plans sometime down the line.