Low voltage alert

Mike Shellim 05 May 2018
updated 10 June 2022

One nice thing about OpenTx is that you can tailor your battery alerts according to their chemistry. The snippet below is a battery alert for a LiPo or LiIon receiver battery. It sounds when the voltage drops below a certain threshold for longer than a given period:

L1: a<x, V1={sensor}, V2= {min-volts}, Delay={min-period}

SF1: L1, Play Sound(Beep 1), repeat(4s)


sensor = 'RxBt', 'Cels', 'A1' or 'A2' depending on receiver or sensor used.
min-volts = low voltage threshold.
min-period = minimum duration of low voltage before alert is triggered.

How it works:

Adding a voice alert

The example above uses a simple beep, but a voice alert is more informative. Most sound packs have lowbat and batlow, however these are generic alerts. This "receiver battery low" track will avoid any confusion. To download, right click the link and Save As. The special function must be modified:

SF1: L1, Play track, "rxbtlw.wav", repeat(4s)