RoseOnRails – final steps before the PCB of the locomotive

Hi all.

Today, we finally had the opportunity to talk to our teachers Alexis and Sam about our solution for the implementation of the H-bridge and the BEMF measurement circuit for the motor (of the locomotive). Below are the three solutions we have tackled with so far. Today, after discussion with Alexis and Sam, we finally decided that “the current measurement” method is the most efficient one. The amplifier-based method is definitely too much complicated (further, and OA is often big and expensive…). The method with the 3 transistors works, but is still more complicated than the method using simple current measurement, namely the method have retained. The most interesting about this technique is that it doesn’t require to stop the motor! We can thus measure the BEMF while the motor is running!

Implementation 1 (OA)            Implementation 2 (3 transistors)      Implementation 3 (current measurement)

At this stage, we know how to control the motor. We have also found the references for the components we need to implement this circuit. The next step is to make the layout of the PCB… surely tomorrow!

Regarding the STM32 lab session, well I worked on the serial over usb connection today, but very little… mostly because I wanted to take the time to discover the BLE kits we received on Friday. So, I installed the necessary programs and flashed some demo codes. For now, I’m stuck with minicom configuration… I’ll have a closer look at it tomorrow.

Valeh VALIOLLAHPOUR AMIRI