Finishing up the coasterbot electronics (mostly)
After building the Ardweeny, and modifying the servo motors, there was only one major bit of soldering left: the breadboard voltage regulator.
The Ardweeny requires an input voltage of exactly 5V, a common requirement for many chips. This is solved by using a voltage regulator. This is available as a simple component ($1.59 from RadioShack) but for best results you need to add capacitors and so on. Solarbotics makes a nice kit that gives voltage regulation to both sides of a small solderless breadboard, has a switch, and allows for adapter input as well as a battery. This was included as part of the Jameco bundle I started out with.
Putting this one together was pretty straightforward. Some soldering and that was it. The instructions suggest adding the male header pins by seating them in the breadboard first then putting the board on top of them. This was a clever idea that worked well.
To test, I plugged in an old adapter that was too flaky to be used for its original purpose. The regulator converted it into a steady 5V. Here you see the regulator circuit at the top of the breadboard (in red) and the Ardweeny hooked up to it running vertically, happily blinking green.
Voltage regulator and Ardweeny, plugged in and blinking.
The circuit has a serious time constant built into it. Presumably this is to reduce electrical noise. When the power is switched off, it takes several minutes to get down to 3V. Clearly, you don’t want to rely on the regulator switch for fast cutoffs.
This wraps up most of the electronics for the project, other than connecting wires. The H-bridge chip, used to control the servo motors, does not require soldering. The next steps involve working on the robot body, then programming.