RoseOnRails – WIP

Hi everyone !

Short sum up of my work since Saturday

On Saturday, I look how to implement our BEMF. I already had some useful explanations from Gleison and Valeh were chosing the component in order to use for our motor. But, on Saturday I got a clear picture (See these useful links 1  2  3 on the way we’re going to implement it  (simple implementation in C). I’ve also looked through Valeh’s of our central station to understand how it was implemented. Unfortunately, I had lend my BLE dongle to Gleison. So I couldn’t make any test to improve the code. Luckily he had gave it to Valeh, so I got it back on Sunday and I started trying to improve the way the code was working. On Saturday night, I realized something was wrong with the suggestion made in my previous post to detect the absolute position of the train.

On Sunday, we’ve met with Valeh the whole afternoon in order to discuss the way we think the intelligence of our game is going to be implemented. Unfortunately, the resolution of the problem of the detection of our absolute took us a very long time (like two or three hours) each time coming up with a solution and then realizing it couldn’t work a few minutes later. We were taking into account the following constraints of our hall sensors and the fact that we had magnet (turn either north or south below our rails).

Hall-effect switches are most commonly used in sensing absolute position, because they require a south pole of sufficient strength to turn the output on and then removal of that field to turn the output off. ”

Hall-effect latches are most commonly used in sensing multi-pole ring magnets for motor commutation, because they require a south pole of sufficient strength to turn the output on and a north pole of sufficient strength to turn the output off. ”

Finally, we came up with a solution I tried to explain it on the rose2014 mailing list but it seems it was way to complicate. So, on Monday we’ve decided to abandon the detection of an absolute position (which was a question raised during our Friday presentation) and we’re just going to detect the change of the kind of pole.

Then still on Sunday, we’ve started to define our architecture and I started to code our classes before midnight.

On Monday, we’ve discussed our architecture with Noémie some questions and doubts were raised. We’ve also discussed our solution to detect an absolute position with Alexis and Sam. But as I said, we’ve eventually abandoned this ambition. We had to make some tests in order to be sure that the electro-magnet use to turn the turnouts weren’t disturbing our hall sensors. We’ve seen that their magnetic (active only when we’re turning a turnout) doesn’t disturb our hall sensors on a distance superior to 8mm. So their will be no problem. We’ve also divided our work between Valeh, Noémie and I. I’ve started to implement our database according to our classes.

Today, I’ve finished to enter all the data we need (I hope) in our database and I’m now implementing the serial thread which is going to change the direction of our turnout.

See you soon


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