I'm currently using a breadboard Arduino Uno clone. Basically a Atmega328p powered using an L7805 linear regulator with a 10uF capacitor on both the input and output. The Atmega328p is connected with a 433Mhz receiver (WL101-541) and two SG90 servos (PWM pins). Basically the signal from the receiver is used to control the servos. The servos need to be driven by 5V(4.8V) as well so their power and ground come from the L7805 as well.
I have encountered a situation where the receiver stops functioning when the servos are under load. I suspect that it is very sensitive to the input voltage and the additional load on the L7805 from the servos causes a slight drop in the voltage.
I have temporarily worked around this by adding a second L7805 and attached the servo power to it. Both L7805 are attached to the same battery. So input voltage will start around 9V then drop to maybe 6.5 or 7 over time.
The circuit power will be a standard 9V battery (perhaps a lithium) as I have weight considerations and am only aiming for around 1.5 hr of runtime.
1) I am looking for information on why one L7805 does not cut it as I believe it is rated for providing up to 1 amp, and the entire circuit appears to be drawing around 0.2A at the time the servos are under load and the receiver is not functioning.
2) Am I missing something, can the circuit be improved? Perhaps through changing capacitors or their placement.