Weight sensors: cheaper if from a commercial product

Instead of buying four weight sensors on Sparkfun (some 7 eurobucks each), I got this brand new Thermozeta Personal 200 bathroom digital scale for less than 13 euros. I'll eventually crack open it for cannibalizing its 4 sensors.

It required a CR2032 battery... which I replaced with 2AA. Apparently it complains "LO battery" when voltage drops below 2.6V. Its control circuit performs a 3-second wake-from-sleep self-calibration, and goes back to deep sleep mode 10 seconds later. Maybe it's better trying hacking the entire Personal 200.