I’m thinking that the main problem with the puck design is the reliance on measuring force at the bottom of the bottle, which can be affected by the wire basket, which can absorb some of the downward force. This requires the puck to be adjustable, which turns into a practical problem. I’m thinking that conductive ink on the surface of the bottle lid connected to a capacitive sensor may create a more reliable signal.
We could use a chip to handle most of the measurements. The PCF8883 is a capacitive proximity switch with auto-calibration, large voltage operating range and very low power consumption. I’m ordering an evaluation board for this so we can check it out.
