I'm building a robot which is actually a rotating ball. All my circuitry will be inside this ball. I'm using a Raspberry Pi as the brains. Apart from Raspberry Pi, I've an H-bridge IC (L298N), a 6-axis Accelerometer + Gyroscope (MPU6050), and probably some more additional digital components. These will work with a 5V or 3.3V supply. Another set of components are electromechanical devices like a 9kg torque servo and 2 1000RPM DC motors.
Here are my questions:
- Everything will work on battery. I can get a 3.3V and 5V supply from a 9V battery using L1117-3.3V and 7805 regulators respectively. I know that it's not at all reliable to share the power source of the control circuitry with high load devices like motors and servos. Should I have a dedicated separate supplies for electromechanical components and the control circuitry?
- Servo will run on 6V supply and motor will run on a 12V supply. How should I go about this one? Again, separate batteries for servo and motors?
- Can of this work on a single high capacity battery, somewhat like 10000mAh?
Here are some of my calculations:
Servo current (6V): at no load: ~450mA, at around 6kg load: ~800mA
Motor current (12V): at no load: ~500mA, at around 6kg load: ~950mA
RaspberryPi and other digital circuitry (5V + 3.3V): ~600mA (that includes an Xbee)
Thus, the overall current at a 6kg load (with two motors) comes around ~3.3A
It would be really awesome if this thing gets done with a maximum of 2 batteries. Else, it may get messy while placing the batteries inside the ball. Space is limited!