Battery efficient body scale

Hi all,

I have a body scale that I gutted and added an LCD screen with an I2C backpack, an HX711 ADC to read the weight and an esp8266 to run everything and upload my weights somewhere. The housing of the scale allows for 3x AAA batteries and I'd love to reuse that as it is.

The goal is to have the best battery life I can, thankfully a scale usually stays off most of the time, so putting the ESP to deep sleep as well as desoldering all the LEDs of my components, etc should keep the consumption low when it's off.

Ideally I'd like to power it up stepping on it or giving it a kick or something, like the original, but since I'm not sure how I'll settle for a push button, but it must have auto off. Right now I time out and send the ESP to sleep, waking it up with a button that triggers a reset and starts it up.

I was thinking that since a voltage regulator to bring down the 4.5V from the batteries to 3.3V would bee too current consuming (runs when the ESP is sleeping), and I don't want accidental resets once it's booted up, maybe I can just use an attiny as power controller. Basically would be in charge of turning on and off the whole circuit. Power it up when the button is pressed, and shut it off when the ESP times out and signals the attiny to do so.

Is there an easier way of doing this? Am I over complicating it? Also does anyone know how retail digital body scales sleep and are powered up when you step on them?

Thanks!