When most of us get to grips with applying power to a DC motor, to watch it spin round, usually our next task is to determine how fast it is spinning that is, determine it's speed of rotation. There are many different ways of measuring a DC motor's speed including using an optical encoder. Before using a FPGA to automate the task we firstly measured the DC motor's speed of rotation by connecting the digital and analog outputs of a photo-sensor board to an oscilloscope. What we discovered during this first phase of measurements is the subject of this blog post.
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The L298N is a dual full-bridge motor driver available in a 15-lead multi-watt package that is popularly used in Arduino motor shields. The multi-watt packaging is required, since this device can supply a DC current of up to 4A and has a total power dissipation of 25W. When run to it's limits and given the amount of heat this device is required to dissipate, it is not unsurprising during operation to see it tethered to a heat sink. This all sounded so interesting that I decided to check the device out. So an overview of this devices' characteristics and functionality forms the basis of this blog post.
To experiment in implementing DC motor controllers with FPGAs and Microcontrollers I recently bought a 12V DC motor from eBay. Now, normally, one would have a target application in mind and peruse the motor's datasheet to see if the motor is fit for purpose.
However, at this stage of my experiments with DC motors I am only interested in developing the electronics to drive a motor efficiently, as well as gather useful telemetry to send back to a host PC.
Once this initial phase has been successfully achieved I will look at using DC motors in real-world applications like robotics and quadcopters. ...