Fine tuning Boe-Bot line maze (ch 8)

bmcnicho

My boe-bot follows my line, but not very well. It is very slow and tends to "cut corners." It does go from start to finish, but I'd like it to work better. I have read and re-read the chapter and have made some excel charts to try to help myself understand the affects of k and set point, but I'm having a had time applying it to tweaking my program. Plus, if I'm teaching this I'd like to have a better understanding for my students.

Also, my boe-bot does not wait at the start for my hand and does not stop at the finish.

Any help would be greatly appreciated!


Diane

Andy Lindsay (Parallax)

Hi Diane,

Sorry for the slow reply. I recently stumbled across an approach that works better than Chapter 8, Activity #3 for stripe following.

1) Electrical tape stripes should be at least 1" wider than the Boe-Bot's wheelbase on both sides, and start with turns that are 45 degrees or less. So, a 90 degree turn would consist of two 45-degree turns. Curves are fine too. An electrical tape course that's wider than the Boe-Bot can be a hassle. So, we use vinyl sheets (Oracal Exhibition 631 in matte black, not the permanently sticky but the re-positional kind). Here is a link to an example: http://cricketvinylsupplies.com/black-matte-vinyl/#axzz2r9JzGCFz

2) Point IR LEDs and detectors straight ahead (not outward or inward) and down at about a 45-degree angle.

3) Use the "Series Resistance and IR Detection Range" section in Chapter 7, Activity #3 to calibrate your detectors so that the do not detect the electrical tape surface, but do detect the table surface.

NOTE: I've noticed that geometric adjustments can help fine tuning. For example, if there are still some surface detections over the tape, point the receiver straight ahead to make the detector less sensitive. To make it more sensitive, point both receiver and LED down at a steeper than 45 degree angle.

4) Use FastIrRoaming.bs2 from Chapter 7, Activity #5 to navigate the track.

5) Tune for corner cutting by pointing the right IR LED a little to the right and/or the left IR LED a little to the left.

6) Optionally, use the Your Turn from Chapter 6, Activity #1 to halt under a desk lamp at the end of the course.

Andy

bmcnicho

Thank you so much for your help! The class is 2 weeks away and I was getting nervous.... One of the biggest reasons I picked the boe-bot kit was that so many reviews mentioned the wonderful support from Parallax.

I'm off to try your suggestions.

Diane

Andy Lindsay (Parallax)

You're most welcome, and keep us posted.

Thanks, Andy

bmcnicho

It worked! But I ran out of electrical tape, so I need to wait for my order of vinyl sheets to arrive so I can finish my track.

Thanks again,
Diane

bmcnicho

That vinyl tape is great! It's so much easier. I used it on a shower curtain because I have very little storage space and money. Here's a picture of it. Class starts tomorrow!