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On the board again…

Just can’t wait to get on the board again.

Hello World!

The last two days were dedicated to boards. Yesterday Adele and I played with our nRF51822 dev kit. We managed to flash a little example program using radio to communicate (Benjamin already showed you what it looks like). We also published a little tutorial to help our classmates to make everything work. Then we tried to flash another program using real BLE this time. However it was a little more difficult: we had to write the Makefile because the demo was not shipped with it. In the end, I successfully flashed the software, but it was still not working. Sam explained us today that we had to flash the soft device before. I hope I will have time to investigate more on it very soon!

Today, I kept on my STM32 lab. I tried to make the potentiometer work, but the force was somehow not strong with me today. I will try again tomorrow. In the meanwhile, I managed to make my buzzer work. But as I respect the ears of my classmates, I didn’t try to compose a full 8-bit symphony (yes, this sound really makes me nervous!). Then I started to work on Serial over USB, but it is not yet working. I keep hope alive!!

In addition to that, I have a lot of things to do, especially for associations and internship search. I hope I will manage to finish everything by the end of the week! And also, I’m working on a side-project, but it deals with Web so you might not be very interested in it…

May the force be with you!

RoseOnRails – PCBs

Hi.

Today was mainly lab session work on the STM32 board. I finally understood the concept of Chibi shell!! I even added some “personnalized” commands to expand the shell 🙂 Funny!

Then it was the “beep” step: run the buzzer of the STM32. It was rather straight forward now that we have well understood the concept of PWM, duty cycle, and so on.

After that, I started to think about how to use lwIP to carry out an HTTP request through the web. Though I haven’t had enough time to go too far in it yet…

This morning I also “played” with my BLE Evaluation Kit. I managed to flash some example programs and test them.

Tonight, Gleison and I started the conception of the PCB of the locomotive. But as Blyste mentioned, we’re still missign a lot of things. So, we rather started by creating issues on Bitbucket, mentioning the components we need for our circuit… impatient to have them and start this famous PCB conception at last 😉 !!!

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!

circuit_moteur_loco_sol1 circuit_moteur_loco_sol2circuit_moteur_loco_sol3_3

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.