How do I use 555 as LiPo battery monitor

I am trying to make a simple circuit using an NE555 to essentially monitor a LiPo battery.
The single cell LiPo runs a small boost converter to provide a constant 5 volts to the NE555 which flashes an LED using the standard flasher circuit in the diagram below.

I want the LED to glow constantly (i.e. stop the flashing) when the LiPo voltage is above, say, 3.1-3.3 volts and start it flashing when the LiPo is below this voltage. I thought that I could feed the positive of the LiPo into pin 5 (control) of the NE555 to stop the flashing and the LED glow constantly when the LiPo is fully charged but this does not work.

Does anyone know how to get this simple circuit to work as outlined?

Google is probably better than an Arduino forum..

I found:

https://leadacidbatterychargercircuits.blogspot.com/2017/02/battery-low-level-indicator-using-timer.html?m=1

Thanks for the reply Hammy but I had trawled Google before posting.

The link you post is different to what I need in that the LED stays off until the battery voltage falls and then its supposed to start flashing. (Not sure how it will go astable and flash with the threshold pin tied to ground and the only capacitor connected across pin 2 and ground)

I want the LED to stay lit until the battery voltage falls and then start flashing.

Any one know how to achieve this?

lemming:
The link you post is different to what I need in that the LED stays off until the battery voltage falls and then its supposed to start flashing. (Not sure how it will go astable and flash with the threshold pin tied to ground and the only capacitor connected across pin 2 and ground)

I want the LED to stay lit until the battery voltage falls and then start flashing.

Any one know how to achieve this?

Well, the Arduino comes to mind. Analog inputs to monitor the LiPo voltage, Digital outputs to turn LEDs ON and OFF and even to flash them. Maybe, even, consider a Trinket:

https://www.adafruit.com/product/1500?gclid=CjwKCAjw0oveBRAmEiwAzf6_rFEg3omUNXXHIpHjdKI3deIzw0KBFTjQ2T6qIxQBHQv9XJc9u5j-sBoCTmYQAvD_BwE

Otherwise you need something like a comparator to monitor the voltage and perhaps the 555 to do the flashing.

I suppose you could fineggle one of the 555's comparators to do the comparator part, but then, being tied up, it might be hard to get the 555 to do any flashing.

hammy:
Google is probably better than an Arduino forum..

I found:

Or not probably better.

Does not do what was asked, does not even flash - relies on a flashing LED if you want it to flash.

Poorly written article overall.