After a break ..

... we got back to work.

As we had some deadlines the last weeks, Lego was placed a bit on the background, but for the NXT couple of weeks, the printer is our top priority.

8h10, monday morning, ... what we had hoped would be a very productive day, some even hoped the printer would be as good as ready, started with a bummer. All three of us weren't in our most productive mood and the work didn't proceed as hoped ..

In the afternoon, our biggest concern was trying to connect our pc and the NXT module with bluetooth. We are now writing a c# program to show our printed page on the pc. The bluetooth didn't work as planned, but by the end of the day, we were able to get our values from the light sensor delivered in our c# program en are almost able to recreate the image.

So what started as a less productive day eventually ended with finishing all we had planned.
Up to the next meeting!

Breaking the code

     Today, it was all up to programming our printer.
We thought a little break on the construction would give us some inspiration on how to overcome some problemes we're facing for the moment.
So all Labview it was, and it went quite a lot better than we had planned.

     To start with, we tried to program our pin to write only when necessary and without any errors, it worked from the first time, quite a surprise!

     Next was combining this pin with the movement of our printer and the turning of the paper. Here we discovered some diffeculties which we will have to resolve in the next days. As we couldn't directly find a way to toggle a boolean ( which we need to chance the direction of our printing rail ), we've only managed to make the colour sensor read one line of our paper in combination with printing it down again.

     So this brings us up to this and next week challenge, which is almost completely finishing our project by finetuning all the motors to the correct distance, completing the code and troubleshoot some hidden traps.

Where have we been ..

   It’s been a while since we’ve posted something.
It’s apparently rather hard to bring up the discipline to maintain our blog and we’ve been rather busy with our assignment for Quality Management and it was somewhat of a holiday for us last week. So hopefully this explains our absence and again our apologies and hopefully you didn’t missed us too much and you can forgive us.     But what has changed since our latest posts.

The first meeting after our latest post we almost accomplished nothing and so there is not much to tell about it. We’ve started with the construction of the mechanism to move the scan and print head back and forth but this is not as easy as we thought. Also it became clear that we couldn’t use the ultrasonic sensor to use on the other side of the rail because it wasn’t meticulous enough to use in our construction. So that was not what you can call a very productive day.

     This brings us to yesterday.
Immediately we noticed that we had a problem. The problem we faced was that our cables weren’t long enough to connect all the sensors and motors to our NXT brick. It looked like our worst fears came true: rebuild our construction and setting us back weeks in our planning.
The first thing that come to our mind to solve our problem was asking on the school forum if other people had long cables we could borrow. We had some response from fellow students and also a lecturer that we could use their cables but that didn’t seem necessary because with a knack we were able to position the brick in such a way that we weren’t forced to use other cables or rebuild our construction. Congratz to my colleagues for that!
We also had, and we still have, some problems with moving the scan/print head. I tried to braid some cords to make the drive belt more suitable for the driving of the scan/print head. This seemed to work but sometimes it got stuck and we still didn’t find a solution to solve our problem. So we’re a little bit stuck on that.

     Something else worth mentioning that happened yesterday is that we have a second touch sensor. Regards to our lecturer for that!
Now we can use this sensor to use on the other side of the rail which can be used to determine when the scan/print head needs to return. This also solved a programming problem we’ve been facing.
In the code we’ve written we could use the touch sensor on the other side to function as a trigger to rotate the rollers to move the paper but on the side where we didn’t had a sensor we didn’t had something of that order so that gave us some problems. But now with the use of that extra touch sensor we can use it to function also as a trigger. So again regards to our lecturer.
In the next post we’ll be talking on what we’ve done today .

     More to follow when it’s completed and fully functional.