Detecting physical input

Projects General Guidance
1

I have a project in mind for which I need to detect the location of a physical marker, which then causes an output particular to that location. Imagine a game board with 31 locations. I need to detect which location a user places the game piece upon.

Creating a connection which would be closed when the marker is placed upon the location seems like one way, only I don't know how to extend this to multiple locations. I need to detect if marker is in location #1 versus location #15.

Any thoughts on how this might be done?

Is there another platform upon which this might be more easily done?

Thanks.

2

Magnet and reed switch/Hall effect switch?

3

Optical sensor? LED to shine up, when a game piece is placed, it reflects light down to an optical receiver, analog or digital outputs.
https://www.digikey.com/products/en/sensors-transducers/optical-sensors-reflective-logic-output/556?k=optical%20sensor

4

Imagine a game board with 31 locations

Feel free to provide more details; size of board, size and nature of marker, etc.

5

Is there the possibility of more than one marker present at a time?

6

Well, it's not really a game. That was the easiest concept I could think of to explain it.

It's more a calendar type thing. The user moves an object to the current day, which lights up an LED, and a 16x2 liquid displays shows a message for that day. I'm hoping to use primarily wood, both for the calendar portion (which would be essentially be a long chunk of wood marked 1-31) and the marker also primarily of wood, approx 2.5" by 2.5" or so.

Hope that helps.

The design requires a single marker.

Thanks y'all!

7

I guess once you've arranged for the markers to be placed and stay in position you could affix a magnet to the back of the marker and have a hall switch in each day which switch would be activated by the marker. The hall switches could be either one long string of parallel contacts to a PISO shift register register or be arranged in a matrix pattern.

8

Would such an arrangement allow me to detect which day the marker is placed upon?

That's an essential element... the messages displayed are particular to the day.

9

inventori:
Would such an arrangement allow me to detect which day the marker is placed upon?

Indeed it would. Each switch corresponds to a particular day. You program the Arduino to read the switches and display the correct message.

10

I think I have what I need to get to the next step. I appreciate everyone's input. I had never heard of a hall sensor (but I have one on hand, luckily!) and I'm going to try that. The "exact" location is a conundrum I'll tackle later, if necessary, as I think code will get me most of what I'm after.

Thanks again for being so helpful!

11

If you arrange magnetic reed switches in a matrix you can use the Keypad library to scan the matrix and report the position of the marker. This would allow 31 positions with 12 pins (6x6=36 or 5x7=35 or 4x8=32)