Interactive web site of Télécom ParisTech's ELECINF344/ELECINF381 Robotics and Embedded Systems classes (a.k.a. ROSE, 2012 session).


First life signs of our board

Yesterday we got our PCB soldered, next step is obviously to test it. First happy thing was that the board didn’t get on fire when powering it on.

We created a new ChibiOS project that will be the base for our code. To do things the proper way, we also made a new board folder, which is specific to our PCB. It specifies all the settings of the various GPIOs on the µC, such as the alternate functions.

One minor problem we hit, is that stm32f4 isn’t supported in the openocd build that is running on lab’s desktops, so we had to build master branch of openocd’s git. Thanks to Sam, that was an easy task. After that, the JTAG just worked out of the box.

Once everything was setup, first functions we’ve tested is powering on/off the red led, and the serial port. Testing them made us realize that the serial port has actually been wired the wrong way, TX on the usual RX pin of the micromatch. Hopefully, we aren’t the only group to have failed on that, so we can use SaMoRa’s serial cable :-) .

Another mistake on the schematics we found out, is that one encoder plug isn’t properly usable: one pin is on a timer, while the other one is on another timer. This is no big problem, since it can easily be done in software, and that it seems really unlikely we’ll use encoder.

Yet another mistake on the PCB, is that the plugs aren’t named, so we need a map to know what function is on what plug.

Anyway, despite the various problems, all the features tested are working, so that’s great news !

Pierre-Hugues Husson

Welcome to the world of ROSE, baby Ball-E

Today, while Otilia and Scott tried to learn things about Kalman filter and from Rezero’s final report, and almost commited suicide after :p (don’t worry they’re ok), Pierre-Hugues and I continued the mechanical calculations.

Unfortunately, it appears that our calculations must be false as the result with numerical values didn’t make any sense.

So we decided to make tries with a real ballbot. We asked the Telecom ParisTech Robotics’ Club if we could borrow them some omniwheels and DC motor in order to estimate physically the power that need for each motor. We would like to thank them for accepting and we would like to introduce you our new friend : Baby Ball-E


Matthieu Tardivon

A new intense week is coming

Last friday, we had the communication challenge which put an interesting end to the STM32 practical work (but we know that more should come soon ^^).

The Hexapod team pointed out an interesting software named V-Rep, so I took a look and it seems a bit complicated to simulate a ballbot with it. Therefore I tried to use robotSim and robotBuilder from Cogmation but the program wouldn’t stop crashing on my computer…

As we had found some Matlab simulation code from the existing ballbot project (such as Rezero), I thought the best solution should be to use Matlab and Simulink which seems to be really powerful. My goal for the next few days is to learn how to use it and try to make simulations with (as soon as we’ve finished some mechanical calculation with Pierre-Hugues).

We also made a kind of summary of our meeting with Alexis an Samuel on our Ball-E Google group in order to settle a better communication inside the team.

I hope that next post will come with complicated calculations and some screenshot of our work !


Matthieu Tardivon

STM32, communication challenge and works on the Gumstix

The practical works on the stm32 board is finally finish and complete. There is now just to finish the PCB for Wednesday.

Last friday there was the communication challenge that went well and took us the entire day.


Now for Rose Ace we have to finalize our architecture. So we’re working on a Gumstix this week-end to check that it has enough computing power for our application and that WiFi reception is good, even in a ventilator running at 1000rpm.


Ready for tomorrow

Today, I finally finished the practical work on the STM32 card.

It can sing a Bach’s song received by Zigbee ! I hope that all I have done will be enough to handle tomorrow’s communication challenge (Spare me Murphy, please ^^)

The BallE team had a meeting with Alexis and Samuel and we discussed many things. I won’t detail it in this post because Pierre-Hugues should do it soon and he will also explain some of the mechanical calculations we made the last few days.


Matthieu Tardivon

Personal work

Yesterday, I managed to use FreeRTOS in order to make the green and red leds blink. My STM32 card now looks like a Christmas tree !

However I had trouble today using Expedition PCB, I’m having a hard time trying to connect the microcontroller’s pin to anything else…

Let’s give it another try tomorrow !


Matthieu Tardivon

Last few days’ work

On Thursday, we finished out presentation about switched-mode power supply with both Guillaumes and then we presented it on Friday.

We hope that our presentation was clear enough for everybody and don’t hesitate to ask question about switched-mode power supply, we will be happy to help you.

On Friday afternoon and today, I continued working on the STM32 practical work.

Simulation about Ball-E should be made during next week.



Matthieu Tardivon