RoseOnRails – motor and LED

Hi everyone!

This morning, Gleison and I re-did the experience to measure the inductance of the motor (we had made an error in our circuit, related to the reference voltage of the ocilloscopes..). We also re-measured the internal resistance of the motor and after several measurements found an average value of 31ohms. For the inductance, we found a value of about 6mH, however the measurement seemed to be incoherent at some point, so we’ll use the inductance-meter Alexis said we would receive in the following days. We then did the Simulink simulation (with the motor controlled with the PWM and the H-bridge) and visualised di/dt with the change in PWM frequency. However, the simulation didn’t re-produce the result we were waiting for and there were several things we didn’t understand and (in spite of researches on Google for help with Matlab and Simulink) didn’t manage to perfectly control. After discussing with Alexis we decided it was just a loss of time to try and determine it so precisely. So we well just take a PWM frequency of about 20kHz.

This afternoon, Yann, Gleison, and I talked about the LED and Yann told us that according to Sam we could simply control the led strip with GPIOs (no need for SPI). While Yann was busy with the PCB, I decided to write the code to control the led strip with one GPIO and one timer (in PWM mode), on our STM32 Olimex board. Since I started this pretty late, I finished it at about 11h30.. and Télécom students know well what that means: “Bonsoir. C’est l’heure svp.” (Hello. Time to leave please.). I was a bit disappointed since I would have liked to test and do the changes until it would (finally!) work. But well, we’ll do it tomorrow then! (can’t wait 🙂 !!)

Regarding BLE, well unfortunately I didn’t have the time to work on it today. I will try to do so tomorrow though.


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