05

PCB Design Week

Halloween or bust

In week 3, I talked about designing a controller for the satellite dish robot. I didn't really have a great idea of what the satellite dish could do besides being alive, but after some thought I decided the perfect job for a semi-sentient big mouth would be to hand out Halloween candy!
My new concept is that come Halloween Mr. Satellite dish will sit on the porch with a bowl full of candy offering it to the children who walk by. When the satellite dish's faith in humanity is high, and hunger is low it will kindly offer candy to whomever approaches. But eventually once it's grown weary it will start to take the candy for itself! Figures 1 & 2 offer a graphical abstract of the interaction.

Design

So I thought it'd be best to have a couple display LEDs to broadcast the robot's internal emotions:

  • Orange for the robot's hunger
  • Red for robot's evilness
  • Green for the robot's faith in fellow man.
As well as some buttons to alter the state (though nothing so clear as "improve faith" or anything like that)
I poked through the architecture shop for suitable electronic parts and found LEDs as well as buttons as well as a PIR sensor - score! Having never wired up any electronics before, ChatGPT was actually very helpful for providing context on when a resistor is needed etc.

Without too much of an issue I was able to load the parts into KiCAD's library, adding hand soldered resistors when necessary, LED & button footprints courtesy of the ComponentSearchEngine, and breakout pins for the PIR & 2 motor drivers which will eventually be necessary.

Then the footprint which was also pretty straightforward involved a little bit of fudging around with the wire layouts and thicknesses.
I opted to really set a very thick ground wire since basically every component feeds into it. thinking of the wire sort of like a tree, where the trunk is the thickest (where all connections run together) vs the thin branches (where the connections feed into each individual component). I bet there's a more structured way to do this than just eyeballing but eyeballing is what I'm going with this week.

Finally, here is the finished Png complete with labels for the LEDs & Buttons. Ready for the mill!