Scoutbot V0.1

Well everything is finally wired up and ready to rock and roll. 3 Ultrasonic sensors facing forward, left (45deg) and right (45deg) as well as a forward facing Sharp IR sensor and a rear IR sensor.

Not enough space

Sensor wires are small. So small in fact that screw terminals sometimes can't grip them properly and the available pin crimps that I had just wouldn't crimp correctly. I needed some kind of breakout board for them to attach to the Mega screwshield.

In addition to this there wasn't any space left on the Wild Thumper to mount anything without building a 2nd level. A re-design was needed.....

Not enough pins! (MEGA Screwshield)

After connecting up the ultrasonics and IR sensors to the board I started looking into how many I/O pins I had left on the Arduino Duemilanove board. The VNH 5019 Motor shield requires 8 digitals and 2 analogue pins. This left 6 digital pins and 4 analogues, of which 3 ultrasonics needed 3 digital pins and the IR sensor an analogue, not much room for expansion!

Something bigger and better was needed....the MEGA :) 54 digital pins and 16 analogues should allow plenty of expansion!

Sensors!

While thinking about how to mount my ultrasonic transducer onto the chassis I started thinking about other sensors that I would like to use and an actual purpose for the robot. To start with I wanted the robot just to be able to do basic collision avoidance. As such would a single ultrasonic sensor be enough? Should I mount it to a servo motor so it could pan, or should I buy a number of the sensors? Would I just want ultrasonics or should I investigate IR (Infra red) as well.

I decided as the Seeedstudio sensors were relatively cheap I'd buy a few more along with a Sharp IR sensor. I also needed some kind of mounting bracket. Active Robots had a range of brackets, but as with most things on the internet I had no idea what they would actually be like once I received them. I decided on sampling a few types.

• Lynxmotion MPSH-01 Multi-purpose Bracket
• Active Robots UB1S3 Bracket (All Sharp IR and Devantech Ultrasonics)
• Active Robots SPB1S3 Panning Bracket

The Sharp GP2Y0A21YK IR sensor mounted perfectly on the UB1S3 bracket as advertised, however the Seeedstuido Ultrasonic module was a close fit to the panning bracket but not a perfect fit (Nothing a needle file couldn't handle).