So if you're wondering how one actually gets from writing code to physically moving motors then you've come to the write post! The combination of motor controllers and micro-controllers allows us to do such things. Our motor controller is called the DRV-8848 BOOST. It's a brushed DC motor that can take a peak current of 2A and is therefore compatible with our motor. Also, it's a booster pack to the MSP430 MCU(Micro-controller Unit) which ensures compatibility and easy connectivity. But why are we using a motor controller in the first place? The current from the MSP430 is too small to drive a motor. So the motor controller acts as a current amplifier, feeding the motor a high current signal thus allowing it to spin.
The integrated chip on the MSP430 has to be programmed by the user, so it can provide us with some electronic sorcery called PWM (pulse width modulation). What is PWM you wonder? As the name suggests, the width of a pulse (which in this case is a square wave) is varied ,allowing us to vary the voltage at the output. Therefore, to increase the output voltage we have to increase the width (on-time) of the pulse. This makes PWM perfect for controlling power supplied to our DC motor.
So, the PWM signal is sent from the micro-controller to the motor controller, which is then outputted to the motor as revolutions. These revolutions translate to speed (revs per minute), thus the PWM voltage is proportional to speed. Therefore, by attaching the power rails to the motor inputs and connecting the motor and micro-controller up, we have a fully controlled motor. And what does all of this look like in the shell of a Mini Cooper Scalextric car you may be wondering?
Well.... we call it the monster mini! But do not be scared as we can significantly reduce the size by putting all this onto a custom PCB. Only time will tell. But for now its onto testing our beast.
Thanks for reading and until next time!
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