I have a couple of battery powered radios that do not have an in built voltmeter or low battery cut off. After considering various options I settle on the DC Beeper Kit from Jackson Harbor Press
At the press of a button this kit announces the voltage in morse and provides both a Timer and Low Voltage disconnect function.
Whilst it functioned as expected and fine for a simple inline volt meter, I felt there was room for improvement. Following an email exchange with designer Chuck WB9KZY I received a new chip with a minor modification. Now if Pin 6 of the micro is grounded when the unit is powered up it will announce the voltage straight away, and then continue to function as per the original design.
In this configuration the DC Beeper can be used like a simple voltmeter without the need of a third hand to press the button, or as my case on connection to the battery pack I have an instant announcement of its voltage.
To facilitate alignment I changed the supplied trimmer for one that would allow for “side” adjustment