MOZ, I think you know more than I do at this point - reading the work you've done and thought you've put into this. I'm still making toys , you've got something really amazing here. I'm curious, however, why you moved AT90 to the left side, isn't that the smaller PCB? It doesn't really matter, just wondering. Will there be space in the Left side case to fit optional BT & LiPo? Just thinking out loud.
Just a few minor thoughts:
- I believe R24 should be a 33 Ohm resistor on the Din line for the WS2812b LEDs.
- related to that, with the halves split, I wonder if there should be another 33 Ohm on the Din for the right half. The WS2811 sheet actually has them on every IC (but they don't seem to be necessary) - just thinking with the split, it might help smooth out the data signal.
- I really like that the Planck PCB includes a small SMT indicator LED so you know the microcontroller is running - I'm adding that to the bottom of every project at this point, it's a great feature - it's also easily disabled by just removing the LED or resistor - I'm assuming the other LEDs are for caps & layer indicators
- Even though you've thought of everything, it might be nice to break out some of those extra pins Just In Case
Thanks for the compliment Regack, it means a lot coming from you. I mentioned a little earlier in the thread that I will have two extra rows width of space on the left side of the left PCB to add symmetry to the design. I wanted to utilise this extra space, thus I implemented the extra features.
- For R24, 330 ohm ohm is what I read in almost all applications using SparkFun/Adafruit/Arduino devices as well as the resistance sold by most eBay sellers. I'm guessing one 330 on the line coming from the MCU is enough rather than one 33 ohm on each Din->Dout.
- Good point, I should probably add one, will do so.
- I have 3 layer indicator, 1 CapsLock indicator that will be top facing. Besides this I'll be having two more SMD LEDs on the bottom for charging status and also will add one more for BT status. LEDI1 will also be used to signify that the MCU is in bootload mode. I guess I'll throw in one more on the bottom and to reduce the total current draw, I'll recommend slightly higher value resistors.
- Extra I/O pins is going to happen, I just haven't put it in the schematic as I want to first layout all the necessary components and tracks; and space permitting, I'll probably breakout as many of those extra pins as possible.
Just to give an update, I looked into the HM-10 BT module which is quite cheap and should be implementable if there is space on the PCB, so you can mount the HM-10 module directly on the board.
Now if we put the HM-10 on the board, we introduce a 3.3V regulator, and then I though, if we are going to do that, we might as well use it, so another wild idea, microSD card, should be great for those that travel with their board. You can store files, portable apps, etc on the microSD. Still have to look into speeds and other aspects, but just a line of though. Adding hardware support is not going to be hard, it's the software side I foresee myself struggling with.