Butterbot: Arduino Nanosumo

Let's Make Robots Robots
1

This is the Butterbot. I started out wanting to make a robot that could butter my french toast. Then I got the idea to make it a 1" cube robot for Nanosumo at Robogames. I used my vacation to get it done and I finished midnight before the competition. When we were weighed though, everyone was close to 25g and I came in at 10g, so I knew in a push fight I was hosed. I feel, however, it was mission accomplished.

I had more pcbs so I kept making more and refining the design. The Butterbot is based on an Atmel Atmega328p, like a lot of Nanosumo designs. It has planetary gear motors, 3D printed wheels and axles and shell. It has bearings in the wheels. The sensors are 2 forward facing object sensors (IR targets), 2 line sensors and wheel encoders. I also made an accelerometer "shield" that can be plugged in on top. I have written code for sumo, line following, IR communication between robots, motor balancing with the encoders and tilt sensing with the accelerometer. Also, I made an attempt to sell them, but I don't think it will be too popular unless I can get the cost down.

My website is here: http://www.wweilereng.com

If you live in the Bay Area, come to my electronics meetup, it's totally fun and free. http://www.meetup.com/San-Jose-Electronics-Robotics-and-RC/

I plan to make some videos of the Butterbot in action. I will post those soon and put a link in. Here is a video of the Nanosumo competition at Robogames, with one guys sumo catching on fire. http://www.youtube.com/watch?v=y8Ld_FO7uSo Bill Weiler

 

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/butterbot-arduino-nanosumo
2

To James

The lipo is a 50mAh capacity. I do so many different things with the bot I have never actually figured out an average runtime. I say in Nanosumo about 10 minutes.

I showed the robots at Discovery Days science faire in San Francisco a couple weeks ago and I had a real hard time doing continuous demos. People were just coming at me and I couldn’t charge them fast enough. Kids sometimes would walk around me and take the robots off the chargers and run them (a classic kid solution :slight_smile: It was tons of fun.

When I run out of PCBs (I have 11 more), I am going to redesign so the batteries come out. That way I can have one or two sets of batteries charging while running the robot.

 

3

To Stephen

I had a problem with the encoders. An optical sensor would be best but I couldn’t find one small enough to fit. Also, I wasn’t sure I could maintain an air gap with all the flexing and wobbling of the wheel and axle. I ended up putting 10 1mmx.05mm magnets around the wheel and using a hall effect sensor. The magnets are neodymium and I have to heat them to lower their magnetism or they overwhelm the sensor. When it does work, it’s great, but it is not too consistent across robots.

 

 

4

Have you seen

http://www.supermagnetman.net/product_info.php?products_id=399 ?