Only buy this is your radio system lets you set failsafe positions.
As other people have mentioned, if you lose radio control signal you will be unable to turn the alarm on.
If you have a failsafe you can set the switch position to turn on the alarm if signal is lost. ( I will set up mine so that the alarm is triggered at the same time as my RTH).
If you do not have a failsafe, you can buy another version that you connect in line with one of your servos. If no movement is detected after a minute this activates the alarm.
Achtung, der HobbyKing®* Discovery Buzzer funktioniert nur bis max 5,8 Volt!!
Attention, the HobbyKing®* Discovery Buzzer only works to max 5.8 volts !!
Wird er mit einer hö*heren Spannung betrieben, gibt er bei aktivierten Kanal kein Signal.
If it is operated at a higher voltage , it outputs no signal when enabled channel .
This thing is useless if you lose a model because of radio signal failure, you won't be able to trigger it with your transmitter. Recently lost a 250 mini quad in some forest because the radio gear failed and would not activate the buzzer. Certainly not a fail-safe way of finding a lost aircraft.
Good idea tankd0g, unfortunately Morla I am using the stock Turnigy 9x Tx and Rx which does not have a settable failsafe feature. In the future I'll be using a standard 5v buzzer connected to my Naze32 which will become activated when the Naze senses that the Rx is no longer receiving signal.