Arduino Doodlebot

Ok so here's my problem with my doodlebot. The code runs perfectly, however, when the doodlebot begins dancing, the back wheels lift off the ground and stunt the bot from moving fluidly. I realized that when I removed the marker and the cardboard, the doodlebot hopped up and down perfectly which has me thinking that there is a weight distribution problem. What would be a good way to add more weight to the back of my doodlebot, or any other solution you guys can think of would be greatly appreciated, thanks!

Here's a URL for the video of my doodlebot, https://vimeo.com/265116405

It's hard to see how the marker system works from your video. Does the problem still occur when it's actually drawing?

When the doodlebot is actually drawing, the problem doesn't occur. But only because it doesn't bounce up and down which is not part of the drawing program. The problem does not occur when the marker is all the way down because it stabilizes the doodlebot and its weight. I really don't know what the problem is, was hoping u could tell me ^^.

Kur0kaze:
When the doodlebot is actually drawing, the problem doesn't occur. But only because it doesn't bounce up and down which is not part of the drawing program. The problem does not occur when the marker is all the way down because it stabilizes the doodlebot and its weight.

That's what I suspected. So it seems like you are wanting to use the DoodleBot at least partly for a use it wasn't designed for. Please provide details of what you're trying to accomplish.

Kur0kaze:
I really don't know what the problem is, was hoping u could tell me ^^.

Sure you do. The ultrasonic sensor and marker mount puts too much weight off the front of the robot. Since it only has three wheels this causes it to tip onto two wheels during sudden maneuvers.

Aright, here's my struggle, we still need to 3d print a camera holder and a ultrasonic sensor holder for the doodlebot and my design is very similar to the cardboard design that you saw in the video. I'll attach a pic of my Creo assembly. But overall, do you have any tips or ideas for how I can neutralize the weight of my doodlebot? Thank you for all the help btw.