RCX: Help with plotter model from CD instructions (3800 Ultimate Build

[SheepEater]

The paper keeps jamming or doesn't move evenly. And letter size 8'5 x 11 seems to be a bit too large :(

Anyone else here has built it?

[DrJB]

I did build it many years ago, was working fine, but would only write the letter L. If I recall, you need size A4 paper, which is 210×297 mm, and that's a bit narrower/longer than 8.5×11 inches.

Edited November 24, 2013 by DrJB

[SheepEater]

Why did it write only the letter L?

Was it because the program stopped, the sensors didn't work properly, or the fault was mechanical?

[DrJB]

Why did it write only the letter L?

Was it because the program stopped, the sensors didn't work properly, or the fault was mechanical?

I do not recall the specifics. This was in 2003 and I had just purchased the ultimate builder's add-on. I simply tried the program that came on the CD but never tried anything fancier. I do not recall whether that program wrote all 4 letters or only L, and then it was up to the user to develop code for the other 3 letters. I recall though that I quickly disassembled it, to try a different 'machine'. So, I'd say it only wrote the letter L (repeatedly, I tried running it several times) because that is all the program could do. Not a mechanical issue.

Edited November 25, 2013 by DrJB

[LegoPanda]

i built the plotter for the ev3, but it doesn't fit a4 and the pen doesn't stay in that good

[DrJB]

My recollection is that, the EV3 printer prints on a ROLL of paper, or at least, that is the one my son built. I bought a big roll of scratch paper from Ikea (was around $5.00), and cut very long segments from it.

[LegoPanda]

yeah, i tried cutting it but it wasn't that straight, and the motor on the wheels doesn't really work to move the paper

[DrJB]

yeah, i tried cutting it but it wasn't that straight, and the motor on the wheels doesn't really work to move the paper

It was difficult to get it to work as the instructions are not very clear on how to feed the paper. We did manage to get it to work, but it was not obvious. I can tell you that it does work, but you have to keep on trying different paths for the paper.

[SheepEater]

Okay, I managed to get A4 size paper (with scissors) and all the mechanicals finally worked right.

With the remote.

Sadly, the technic cams that switch the touch sensors on/off constantly do so too fast for the program to register it as a rotation.

So the plotter can't be programmed out of the box.

Unless you rebuild it with proper rotation sensors... (which don't come with the 3800 set so I would consider it cheating to use them in the build)

Edited January 25, 2014 by SheepEater