Woah hey I haven’t updated since last year. Well here’s a post. Here’s some backstory behind this one: Last time SparkFun had a Free Day, I won $100 after entering a ton of Captchas for several hours and getting lucky. One of the things I spent it on was continuous-rotation servos because I felt like trying to make a robot of some sort. I once tried modifying some regular servos to be continuous-rotation but I pretty much just ruined them, so I don’t want to try doing that again.
In any case, here’s a quick attempt at a simple robot that just moves forward slowly. The wheels were made from parts of a VHS case which were then taped to the servos. I guess the main issue is that it’s USB-powered so it has a really limited range. I tried using a 9V battery to power the Arduino but apparently that isn’t enough to power two servos (I could hear them clicking, but not moving), so I’ll need an extra power source specifically for the servos. The problem is my lack of battery holders.
So I designed this Kyubey papercraft this weekend, with the idea based on this image on @kevinchai’s twitpic. It’s Cubey because it’s a cube (well technically a rectangular prism).
Cut along the solid lines, fold along the dotted lines. The ears and the gold ring things are meant to be folded back on themselves so that they’re colored on both sides (I’m seeing a lot of people who don’t get this! It’s somewhat important!). See the images in the gallery if you’re confused. I didn’t add the tail to mine because I didn’t glue the back closed, but basically cut along the solid line on the tab on the back part of the main body and insert the tab from the tail. If you make one of these, post it here, I’d like to see it!
I also added electronics to it (I am terrible at soldering; you have permission to laugh at the pictures of the circuit)! One servo for rotation of the entire papercraft, another servo and a rubber band for moving the ears up and down, and two photocells (one on each side) to sense light. I have it so that Cubey will turn either toward or away from light depending on what I set in the program. I tried adding remote control, but my IR receiver kinda broke somehow. Here are some videos of the other stuff, though.
And more on the channel. Image gallery in the full post.
Here is the completed room mapping final project! Since last time, I’ve added a very useful smoothing option that makes the plot look less like a bunch of random jagged edges and more like a recognizable shape. There’s also an option to choose different types of shapes to plot with, which makes for some pretty artsy-looking results. It is surprisingly fun to play around with the smoothing options, textures, and shape types, as you can see me doing in the video.
The Arduino/Processing source code can be found here, and if you just want to play around with the plotting program (I’ve included some sample files), you can download an exe file here. You’ll need the ControlP5 library if you want to modify/run the Processing code (not necessary for the exe).
Here’s a follow-up to the previous room mapping post. The scanning process is more efficient now, with less wasted movements (and thus faster scanning). Rather than going all the way back to the beginning of a column (for lack of a better term) and scanning down every time the end is reached, it just starts scanning from the bottom up.
The program has been improved too. Aside from the pretty menus (made using ControlP5) and graphical options such as color changing, I’ve added a function that checks the ratio between every side of every quadrilateral. If the ratio between any two sides exceeds a certain threshold (chosen by the user), the quadrilateral isn’t drawn. This makes it so that you don’t have a bunch of really long quadrilaterals connecting points that aren’t actually even connected in reality (see the old video for an example).
Of course, I’ve only shown one of each in the photo. They were a lot smaller than I had expected; I put a penny in the image to give a sense of the size of these things. The solar powered car doesn’t really seem to work, but I guess it might just be the lack of adequate sunlight in my room. Gonna start trying to make something with the lasers and servos some other time.
I’ve also ordered some other stuff from DealExtreme about a week ago, and those should arrive some time in the future.
My final project for the Arduno microcontroller class is this 3D room mapping thing. It still needs some work but here’s basically what it looks like. An ultrasonic distance sensor is mounted on a servo (which is mounted on another servo), and records the distance of objects located at various angles. Two angles and a distance from the center make up a spherical coordinate system, and those coordinates can be plotted.
This semester I’m taking a course about Arduino microcontrollers. One of the things included in the materials we got was a servo, and the first thing I did on the first day was looking up how servos worked. I didn’t know there was a servo library for the Arduino, so I ended up writing my own program to change the duration of the pulse sent to the servo based on some serial input (which I also had to look up, since we hadn’t learned it yet). I thought it was really neat and I ended up just playing around with it a lot.