Most commonly, the speed and direction of the motors in a micromouse or other small robot will be read from quadrature encoders connected to the drive train. One of the great things about the STM32F4 processor is that it can read these directly. Quadrature Encoder Signals A quadrature encoder generates…
This micromouse thing is a bit tricky. I have not been happy with the accuracy of the results I have been getting with Decimus. Occasionally, a move is significantly shorter, or longer than intended. Looking at the code does not help – either the code is fine or I just follow the same thought process leading to the same errors every time I look. There is, however, something odd about the encoders.
The LS7366 is a 32 bit counter with a direct interface for quadrature signals from incremental encoders. There is also an index channel for marker functions. The interface to the microcontroller is SPI mode 0 making it relatively easy to drive with a variety of common controllers. Decimus has one of these on each motor channel connected to the encoders on the back of the Faulhaber 2224 coreless motors. There is very little information about these chips available except the data sheet. This is how they are used on Decimus. (more…)