This is a continuation of an interview Makermasters.com did with RobotGrrl, a teen Robot maker.
BILL: – What caught my attention from your projects was the RoboBrrd. Could you tell me a little bit about RoboBrrd.
ROBOTGRRL: Sure, so one night, Adafruit Industries contacted me after they read my blog, and they said, “Hey, can you do some robot videos for us for our Ask An Engineer video show? We’ll give you free parts for your electronics.” And so I was, like. “YEAH!! FOR SURE.”
BILL: Sweet deal.
ROBOTGRRL: And so I got free electronics, for two RoboBrrds actually, but I sort of burned a lot of servos, so there’s not that many any more, but yeah, so I built up the robot. Originally the videos were supposed to be every week, but I sort of got a little carried away with everything, and so since I got free electronics, and I wanted to be able to teach people how to build a robot. So, I decided to make it out of just every day parts, you know, so pencils and Popsicle sticks just things that people would have so that they can buy the electronics and get it started with building a robot right away.
BILL: The beak on RoboBrrd if very ingenious. It kind of reminds me of, a medieval drawbridge or something. It’s definitely looks like what Leonardo would have designed. How did you come up with that?
ROBOTGRRL: So… one of the things that I really like is the “Unit Circle”, sine and cosine functions. And one of the robots I got a while ago from the Exploratorium in San Francisco was called a “Techno Robot”
”, and it’s made out of cardboard. It doesn’t do much, but it shows how it translates rotational motion into linear motion. When you look at the gear box, all it’s doing is taking one component of a sine or a cosine wave and then it just uses that to do a linear motion. So with that knowledge, I just sort of knew how to be able to make something that would be able to translate the rotational motion of the servo into something that could push the beak out which would be exactly what I would want. The way it works is there’s a Popsicle stick on the servo arm. And there’s the hole inside of that Popsicle stick, which connects two extender Popsicle sticks, which attach onto the two halves of the beak. The holes in the Popsicle sticks are used as hinges so everything is sort of loosely moving. As things move the beak changes. When the servo is directly up (vertical), then the beak is closed tight because it’s being pulled. When the servo moves 90 degrees, so now it is horizontal. Then the beak is being pushed out so it pushed both halves, which makes it open. So basically that’s how it’s done. I still have to make a video for this, and it’s in the making right now.
BILL: Okay. Some of that actually made some sense. I’m not sure about the unit circle portion of it…. I think I was asleep that day in Trig class.
ROBOTGRRL: Hmm… With the unit circle, you can always sort of see what component of the X and the Y is changing as you move along the circle. So if you’re only looking for the X component to be moving, then that sort of exactly what is happening with Robobrrd right now.
BILL: I’ll get my head around this in a second. Editor Note: The author failed miserably. Luckily, Robotgrrl made a video that explained it so even the author could understand it.….
ROBOTGRRL: Well, the two halves of the beak are sort of fixed on a point on the front base. So that allows it to rotate a bit at that point. When it receives a push from the servo and the servo extender Popsicle sticks, then the beaks move around that fixed point which makes it move open. Hopefully, that helps clear it up.
BILL: Did you do a map of the coordinates to figure this out?
ROBOTGRRL: I didn’t use any math specifically, it’s just that we can use math to explain it and sort of see it clearly. There’s actually a really cool project on Makezine Blog a while ago, and it was this contraption, a 3D printed contraption where you moved the knob around in a circle, then these two sticks would also move. So it’s basically converting rotation into linear once again, except that you can see it better, and it looks really pretty. I can send you the link to that later, if you’d like.
BILL: Please do, yeah, because I’m interested in that sort of thing. I don’t know who else will be, but I am. And that’s all that matters because it’s my blog.
ROBOTGRRL: It’s called an ideal harmonic transformer.
BILL: So just a little bit more about Robobrrd. Robobrrd has sensors, one in the middle of its forehead and then one on either side of its ears Could you describe what those are for?
ROBOTGRRL: So the one in the middle of its head is the PIR sensor, and it’s straight from Adafruit shop so it has the little lens on it to help diffuse all of the I.R. for the sensor, and that’s used to detect motion. And the ones on each side of its head are just light dependent resistors, and they just detect light.
BILL: You program in different behaviors based on if the light shines on one of the resistors versus the other.
BILL: Okay, and the PIR I’m looking up because that’s kind of cool. Isn’t the Internet wonderful? I mean, do you think about how long it would take to do this research 20 years ago? Already, I’m at the Piranha PIR site, and I can go – and I’m sure Adafruit has all sorts of information on how to use that.
BILL: I mean, that’s just amazing. I’m sorry to wax Lame there, but that’s the way I’m thinking. So you also use a servo on the base to it to allow it to spin?
ROBOTGRRL: Yeah. That’s a much beefier servo. It has to be because of the mass of the Robobrrd on top.
Click Here to read more about Robotgrrl.
Click Here to read more about Robobrrd.
Click here for Documents to build your own Robobrrd