I am working on a project that uses Sharp IR sensor, an ADC, 8051 micro controller and an LCD Module. the Sharp Sensor is giving correct readings only when its power supply comes from Arduino and the rest of the circuit works on a separate battery. I tried to connect a separate 9 V battery with 5 V regulator to the sensor, also tried giving the sensor power supply from USB ASP Programmer but both results in incorrect readings that vary too little between 1.1 - 1.3 V regardless of the distance to object.
Note: Arduino is also connected to laptop with an USB. U3 is the distance sensor that works great if given power by Arduino