The missing parts to the TECHNOROBOT kit that I got at the explOratorium during the Stanford EPGY AI Program in 2008 have been found! This robot has been transformed many times, the first as an idea/prototype for an emotional line following robot, then a snowplow, and now it will be an XBee messenger robot!
Remember the 3D-printed mechanum wheels I blogged a while ago? Well, maker ROB K636 built a cool mecanum bot powered by four battery packs, an arduino, screw shields and what looks like a motor shield. I really like how he created colored wheels using regular old Rit clothing dye. My question is, why use mecanum wheels other than for cool? Wouldn’t you want one wheel on each side of a square chassis to enable 360-degree movement? The way it is now, it seems like you could use regular wheels and achieve the same range of movement. (Note: the maker has generously shared the wheels’ .STL files on Thingiverse.)
When my EPSON 830U decided not to work for me anymore (printing heads clogged) I thought I could make some use of the still working mechanics of the printer. It’s based on a couple of stepper motors for both axis of motion (print head and paper feed).
So I replaced the original power supply and drive electronics for an arduino board and an stepper motor driver from Adafruit industries. Now I could move the printhead
anywhere on a page. Next step was to add a laser on the printhead and to control it using a PWM output from arduino (so laser power could be modulated from the computer).
Though it only cut thin back color cardboard, it has may uses. I wrote a C program for arduino to control the stepper motors and laser. It receives data from the computer and
interfaces with the old printer guts.
Data format is very simple: each line contains a sequence of integer numbers separated by blank space. Each pair of numbers represents one XY coordinate. Line ends with a CR (0x0d) character (that also shuts down the laser to stop cutting). First coordinate of a line sets the starting point (before reaching that location the laser is off).
I wrote some software running on my iMac that reads a Inkscape SVG file (only straight lines are supported though, use Flatten Bezier on curves to get a sequence of straight line segments) and translates it to the desired data format for arduino and it shows a preview on the screen. Data is sent through a USB port to the arduino. iMac code was written using Processing language (Java-based) so it can run on Windows or Linux too.
If you have an old EPSON printer, you may want to give it a second thought before putting it to the trash.
A more functional train microcontroller… Power is coming from a 12V wall transformer which powers both the Arduino (at 5V), and the shield(at 12V). The shield provides pulse-width modulated DC to the rails. The microcontroller is programmed to control direction, maximum speed, and rate of change. I am using a momentary toggle switch with center off to increase or decrease speed. The computer is reading the current settings from the controller over a USB connection. Hitting the reset button automatically stops the train.
Holy smokes. That was easy. In one evening I soldered the kit and had my model train doing the “PWM-boogie”. Thanks to Lady Ada for making it possible for wantabe hacks like me to do cool stuff! [and] Added a toggle switch and more code, and now it is a functional train controller. I can set the max speed and max rate of change to simulate a real engine while keeping is easy enough for my 7yo daughter to run. All I need is some positional sensing and I can do some auto reversing, ect. I’m amazed how easy you made this for us! Many thanks Lady Ada!
It has the latest arduino and Ladyada motorshield. There are three pair of LED – green and two red. Red ones are closer to each other and lower – when you walk close, his eyes follow you. There are two stepper motors supposed to lift his arms, but they do not work very good. The morots are from CD drive, and are not powerful enough (they try hard though), or may be motor shield does not yield enough power? There is vibrating motor from toy frontloader. With 12V it vibrates way to fast – you cannot really see it on a video, you can just hear the noise, but when you come close, and it suddenly start vibrating – that’s spooky The ghost, just like a bat, relies on ultrasonic distance sensor…
I had recently purchased a pair of 5V stepper motors and a motor driver shield from the fine folks at adafruit industries which seemed perfect for spinning the knobs. The question was how to connect the steppers to the knobs. As it happens I had also just bought a gear set from American Science & Surplus on a lark and they fit perfectly on the Etch A Sketch shafts and the stepper shafts. So I simply needed a way to line up the steppers over the knob gears.
There are few problems you’ll encounter in life that can’t be resolved with the judicious application of a laser beam. I drew up a set of parts in Corel Draw and popped in to TechShop to cut them out of acrylic with their Epilog laser cutter.
I cut most of the parts out of clear acrylic except for the side guides which you can see in blue acrylic. The side guides hold the Etch A Sketch in place so it doesn’t move around laterally.
Here’s the finished, working ToyBot. ToyBot is made from a cheap RC toy car. I took out the radio electronics and put in an Arduino microcontroller and an Adafruit Motor Shield motor controller and some sensors. ToyBot drives around the floor looking for light (or for shade, if it’s too hot). When it finds a good spot it stops and goes to sleep. It wakes up when the light or temperature changes, and resumes driving.