Hey there, I'm back and still living ...
The last couple of days I was finishing off with the schematic and starting out with board layout. Here is the (almost) finished schematic:
Small details might still change as I'm finishing up the board layout if I run out of board space or have tons of board space left. A couple of comments are in order:
- I added a transistor to the heating element of the gas sensor to switch of the heater if necessary because it draws quite some amount of current.
- Some little bypass caps got added here and there.
- I added an external port for the serial interface and an I2C port for additional output possibilities (Hint: Think I2C display).
Concerning the board layout, I have so far finished all the footprints and the basic outline of the board. Next up is placing of the components and routing. I have not yet decided on the size of the caps and resistors, I will try 0812 for easy hand soldering but might need to get down if space is rare (as it is, it seems). More on that soon - I plan to send off the board to be manufactured latest end of the week. So far I stick to my initial plan, yeah!
Some note before I part: KiCad suck. Honestly, it provided me with the worst user experience EVER over the weekend. Once it runs its fine, but finding a version that has everything running is a major pain. I'm no noob when it comes to compiling your own software, but it took me five hours using three operating systems (and two flavors of linux) to find a somewhat stable version. Really KiCad - this is the best you can do?