Hey guys as described here I also want to make a chess board with some arduino support. Here I want to ask some questions regarding the schematic and the pcb layout I am planing to do. @Dmitry Grigoryev describes a way to address the sensors by using a 1-8-demux. Due to the fact that my schematic skills are still not the best please bear with me. Anyway, I want to describe my idea briefly.
Schematic for fieldFor version 1 of our board we planing to integrate photo-resistor to determine whether a figure is on a field or not. For this I want to share a simple schematic:
This maybe looks stupid for some of you but these are my first tries. My idea behind this is to use the photoresistor and the other resistor(where the resistance varies from field to field) as a voltage divider to determine which exact field is triggered by a figure.
Question 1: Is this feasible or does anybody has a better idea, then please share with me?
Communication with controllerWe are aiming to use a Arduino Micro/Nano or Mega if more memory is needed. For the communication we choosed the MCP23017 - I/O-Expander. So every field is connected to one out of 4 controller(64 fields = 4 * 16bit I/O expander). I know its an analog signal but all I need is just a 'hey i got triggered' signal.
Question 2: Is this also feasible or does anybody of you has a better and more clean solution. More maintainable and more expandable for future versions.
PCBI am planing to create a PCB out of all ideas that are expandable for other usecase(e.g. adding ADC etc. or something like this).
Same question as former ones also.
Puhh I hope I added everything and the question full-fills all stackexchange standards. If not, please provide feedback to enhance my question.