How to detect/discourage squirrels from a bird feeder?

Solutions

• Buy bird seed covered with hot peppers (some say this has very little impact)
• Use a Grid Eye (8×8 thermal imager) to detect squirrel
• Spinning feeder (like this)
• Cantilevered cover for feeder activated by weight of squirrel
• Electric shock of various types
• squirt water once you detect squirrel
• Weight based lever for detection
• Compressed air valve from January POTM to “puff” the squirrel