https://github.com/crystal-community/bluetooth
Bluetooth is bluez C binding in Crystal. It has been moved recently to crystal-community organization and is looking for the maintainer.
require "bluetooth"
local_device = Bluetooth::LocalDevice.new
remote_devices = local_device.scan
local_device.close
# remote_devices is a Hash(String, String) of address => name
p remote_devices
=> {
"00:11:22:33:FF:EE" => "Android Phone"
}