How to Get Ahead in Life (Part A)

This is part 6 of my robot series.

Today’s post will take our robot to a new level, but honestly also highlight a bit of a mistake… which will be corrected in the next post. But for now, let’s tackle our heady discussion theme of the day!RoboHead1

Our robot has come a long way since BYFR, but he’s still missing at least one critical bit of anatomy. A head! Heads are really very useful; they pack a lot of our senses into a practical compact package, express emotions, and are convenient for storing hats. In fact, I find them so useful that I never leave home without mine.

In the case of our robot, adding a head and putting his eyes on the head allows him to move the head and thereby expand his field of vision. I elected to go with a minimalistic approach and only have his head tilt up or down rather than side to side. Due to his two wheel design he can already spin on his axis, so making a head that turns side to side isn’t really necessary.

The construction was pretty simple – cut out a head of the same expanded rigid PVC as the body, hinge it to the body, mount the eyes, and set up a servo with a linkage to tilt the head up and down. As you can see in the photo, it looks pretty good. But, ahem, if you look at the video at the end, you will notice that it doesn’t work very well. The reason for this is twofold. First even though a servo looks like it provides a nice push-pull that would be great for moving the head, it is actually not a true linear movement. Neither is the movement of the head, and we notice that the axes of rotation of both are at 90 degrees to each other. The upshot of this is, that the linkage will only work if you have a nice bendy universal joint between them to sort out the difference. Or a really loose, sloppy linkage. (See if you can guess which one I have). To make the two meet up properly, the two need to be coplanar. I will show you what I mean when I have it fixed, but for now it means more surgery to the top deck.

In the next episode, I promise to have a robot that will really be turning heads. Or perhaps tilting heads. Thanks for joining!

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