JohnGaltLine posted:Getting back to this after having a couple days to mess around...
christhetrainguy09 posted:Im just trying to help you cut cost a little. Unless you plan on building this "lego" style (using Shields, relay boards) and not having one pcb with everything on it in the end?
I think I have the costs down as much as possible at this point while being able to offer features that other currently available products do not have. At this point PCB space is the most expensive thing going. A tactile push-button costs a penny. The PCB real estate under that button costs about 6 cents. And no, the plan is a fully self contained board, though I'm still up in the air on using a relay module or placing them on the board. I can match costs either way right now.
I built a test rig on solder-less breadboard with parts I have on hand, mostly as something to use while writing code. I'll post a pic later is anyone cares. The basis set up is using a ProMini as the brains, and a second ProMini acting like an I2C port expander for additional IO. I expect to replace the second uP with a proper port expander chip later on. I used a couple push buttons to simulate insulated rails for now, and didn't bother with any isolation here.
Many hours, and about 35 pages of code later (just under 16KB right now), I have all of the discussed features working on the test rig. I made a couple changes from the above list, combining some things that essentially did the same thing, and adding one or two that made sense while coding. More than half of the work was in writing the overhead that is used by all of the various functions. Ex: reading in adjustment and programing data and saving it, selecting options, and the like. That also take up half the memory used.
As of now the main thing remaining is to add the ability for a manual override button on each of the features, as I forgot about that when writing each routine. Theres a couple other tweaks to finish, but I'd say the code is a good 90% right now, and as a proof of concept it seems pretty sound.
At this point I've also dropped the idea of an external programer. Everything I set out to accomplish was doable without one thus far. The hardware support is still in the plan, but the software will have to wait. For now, my thought is that if anyone needs some custom firmware, it will be simpler to write that on it's own and mail them a pre-loaded uP.
Anyhow, I'll probably get a photo or video up pretty soon, once I finish up the code. Then its PCB design time, I suppose.
JGL
Sounds like you been a busy guy!
- Have you got a schematic drawn up?
- are you going to have it all on one PCB? or is it plug and play boards that plug into the pro-mini boards?
