I’ll be using the Guibot Motorduino for an autonomous car project. This includes L293D motor driver and 7805 voltage regulator.
The other components:
Multi-Chassis - Tank Version with two DC motors (SparkFun)
Suggested Voltage: 3V DC // No Load Current: 125mA (170mA MAX)
MinIMU-9 v3 Gyro, Accelerometer, and Compass
(L3GD20H and LSM303D Carrier) // I2C // Supply current: 6 mA
some other I2C sensors
with total maximum ~30 mA current draw.
I2C LCD module
Operating Current<60mA // Input Voltage:5V
My first question is about the batteries. What should I use for best performance and to avoid overheating the regulator and motor driver? I was thinking about using one battery pack for the motors and a different battery pack for the board and sensors. The car chassis includes a 5 AA Battery Holder. The Motorduino board does not have room to place a heatsink on the 7805.
Supposing you know a better solution using a different motor driver and Arduino compatible PCB board, what could that be?
Do you have links to the parts, or at least can tell us what supply voltages each uses ? A 5 AA pack of NiMH batteries gets you 6+ V (assuming they are all connected in series). That’s barely enough to run a 7805 regulator and get 5V out. Overheating it is not a problem given the currents you’ve posted.
That said … you have some parts that need 3.3 V. I’m not sure if those boards have their own 3.3 V regulator or not. It may (or may not) be advantageous to run another tap off the 5 AA pack. Add a wire from the + terminal of 3’rd battery, which will give you a 3 AA voltage (about 3.6 V). But I’d need to know more about the above parts to see if that’s even worth the bother of doing.
One thing to do is to run the motors directly off the battery pack, don’t use the output of any regulator. The motors don’t need it.