smRobots

Fresh code being developed for the mini_ardubot board is being loaded to:
http://code.google.com/p/smrobots/source/browse/#svn/trunk/projects
Browse or checkout as you please. If you are interested in developing code for this board or AVR robotics in general I can set up developer access for checking stuff in to the project.

After waiting 18 days (13 of those in shipping), my board, hastily named "mini_ardubot" has made it through Seeedstudio's Propaganda PCB service and looks pretty good. A quick explanation of the board is that is a small Arduino-compatible platform (has an AVR on board) that prioritizes servo control and IR communication and has support for ISP and serial (Arduino) development. It also has some nice things like a power LED and a user-programmable LED. Ultimately, I am hoping to learn some things from designing this board so the second, more complex, revision will go smoother.

There are times when a program just needs to give up and ask for human assistance. Suppose a sensor or motor becomes disconnected or the battery is dying or perhaps there is a bug in the code which leads down a dark and dangerous code alley. Below is a short piece of code that provides an error routine which will halt the chip and blink an LED, in this case pin PORTB5 (Arduino pin 13), with up to 14 error codes. Ideally, the function can be called if the program determines it's in a unrecoverable state and can provide a code to tell the programmer where it failed.

It seems like a lot of people these days Arduino for a lot of microcontroller tasks, using the magic Arduino libraries to abstract away the underlying architecture. This time and energy saving platform is a beautiful thing, however, people shouldn't be afraid of "pulling back the curtain" on Arduino and, moreover, they should know roughly what's going on. This post covers the voodoo behind the Servo library and how 6 simple registers control flexible hardware PWM.

Part of the frustration (and the enjoyment) of robotics is that, in addition to getting the electronics working and coding software that acts somewhat intelligent, one must also allow the robot to actually interact with the outside world. Fortunately, tape is a beautiful thing, allowing us to throw together something somewhat functional quickly and cheaply.

About a month ago, I impulse-bought 10 of these micro servos off of ebay for less than $3 a pop. Well I didn't have much use for a 90-degree range-of-motion actuator, but fortunately, with some slightly messy surgery with a Dremel tool, these guys can become a nice gear motor with speed control and everything.