I am using an Arduino on a breadboard setup with an ATMEGA328p MCU. The whole circuit is designed to work in a low-power state and is powered using a 3V (Nominal) voltage Coin Cell. The HC-SR04 is getting a stable Power Supply of 5V from another source (Grounds are already common). However, the issue is that triggering the sensor from the MCU gives no output reading and the distance is returned as 0. I checked the voltage level on the Trigger Pin and found it to be 2.5-2.6V
Since the battery I am using is a coin cell so I suspect that the voltage is being dropped from the nominal value of 3V to 2.5V and the HC-SR04 demands a TTL pulse on the Trigger Pin. Is it not working because it's not being properly triggered by the 2.5V level Pulse? I checked some resources and they mentioned that 2.5V is within the High Level Margin of the TTL signal, so 2.5V level pulse should be able to trigger the sensor or my assumption is wrong?