Proportional Wall Follower for LEGO 51515

[@Builderdude35]

Have you ever used a wall follower in FLL or WRO? Let me know here!

[@OWNEDGAMINGwasd]

Nope, i usually use a set of wheels on the side of the robot to move along the wall, especially for wro

[@Builderdude35]

@@OWNEDGAMINGwasd that is also a solid strategy!

[@andrewzhuo6399]

In 2018 we used an ultrasonic sensor in the front, in the robot I'm planning on using in this years's FLL, there won't be an ultrasonic sensor.

[@Builderdude35]

@@andrewzhuo6399 Why did you choose to not use an ultrasonic sensor this time?

[@andrewzhuo6399]

@@Builderdude35 Partially no room but partially because I am more used to the other sensors, and mostly because I can't find a use for it that can't be replicated by other sensors. I.e. wall following, the gyro or color sensor can help the robot go straight, stopping at a certain point because it detects a wall (motor encoders and motor encoders are much more versatile).

[@shadyalajaty6458]

In my FLL Team, I was the first to start programming. It is all thanks to you and your amazing tutorials. U helped me learn from the basics to advanced programming. Thanks a ton!

[@Builderdude35]

You are very welcome. I am very happy to hear that! Make sure to share these tutorials with your teammates and your coach!

[@shadyalajaty6458]

I was a part of an FLL team called ROBO GENIUS in the last months of 2019, but when we started to get ready for our first competition Covid-19 spread around the world.

[@Builderdude35]

I am very sorry to hear that. Maybe you will have the opportunity to compete again in the future!

[@davidluders328]

In FLL competitions, I recall seeing some teams getting "faked out" by walls LOWER than the ones at their team's practice area. Their wall-following programming would not work because the 3-1/2" walls they had at home were not the same as the 2"-high walls they encountered at the FLL tournament competition.

[@Builderdude35]

That is a fantastic observation. I also noticed in my own experience that the mat itself sometimes "floats" around within the perimeter of the walls, because the walls may be slightly larger than the mat itself, leading to inconsistent distance measurements relative to the wall. Thank you for sharing your wisdom!

[@InventorDBA]

We tried. In FLL, in our third year (into orbit) we tried to do it when doing a few missions, but it never really worked. We ended up just using lego aligners and hoped our bot would go straight. It worked out, though. Also getting the infrared sensor low enough and in the right position was hard, so we just scrapped it.

[@Builderdude35]

Indeed, in FLL it is difficult to execute a proportional wall follower. I think WRO participants find more utility from what I have seen. Thanks for sharing your experience!

[@jaapcilia392]

Hi man, I want to build one today. Any building instructions? And what is the third motor used for

[@shadyalajaty6458]

Hello Kyle, thanks for the awesome video. I have a question can Lego Mindstorms 51515 be programmed with ev3 software?

[@Builderdude35]

No, you cannot program LEGO 51515 with EV3 software.

[@shadyalajaty6458]

@@Builderdude35 Thank you

[@nmaou]

I tried your algorithm and it seems to work fine only when the robot is placed at the correct or almost correct distance from the wall. I used EV3 with the new LEGO classroom application. I had the same problem with the old LEGO EV3 programming environment. In the following situation the algorithm failed. I used a target distance of 20cm so as the robot to follow a line 20cm from the wall. I placed the robot at a distance of 30 cm. The robot turned right and it moved forward towards the 20cm line. But it did not stop at the distance of 20cm but continued moving and turning until it hit the wall. The problem, I think, is that when the robot turns right to move towards the 20cm line, the distance sensor is not vertical to the wall, but it looks at it in an angle. So when the robot is at the 20cm line, the distance between the sensor and the wall is larger than 20cm because that distance is the Hypotenuse of the right angle triangle formed by the sensor, the point on the wall where the sensor looks and the point of the wall perpendicular to the sensor. Am I doing something wrong?? My solution is to move the robot for a few rotations, then use the gyro sensor to turn the robot parallel to the wall so as the sensor to correctly measure the distance to the wall, and to repeat the process until the robot is at the correct distance from the wall.

[@Abinav.P]

Nice Video Dude!

[@Builderdude35]

Thanks so much! Glad you enjoyed it!

[@ThatUntitledPublisher]

How did he make the robot that's in the video, I can't find it anywhere else?

[@blorki]

Just an suggestion, but don't you think you need a new intro? I mean, it's the same for years and its really old-fashioned.

[@Builderdude35]

I think you have a point, and I have been thinking about it lately. I haven't had much time to dedicate towards revamping it, but I think I just might try to figure something out this weekend. Thanks for your feedback, I really appreciate it!