My mom loves watching birds at the feeder, but really hates the plague of grackles that dominate the feeding area. She asked me to come up with a way for her to use a remote (feeder is through glass, 20’ away) to play a loud sound to scare them away. Could use some advice on specific products from sparkfun that would work, but be inexpensive to put together.
Adafruit sells small, pushbutton remotes, RF transmitter and receiver. They should work up to 20 feet to activate a noisemaker. In the wine country where I live, people use propane cannons.