Zumo robot project


Since some time Arduino came to my attention and I really wondered if a nOOb electrician (me) can get some robot/ LEDs/ buzzer/ switches and other things to do something I want. I started with a Arduino Starter Kit (by Arduino) and made the projects as described in the book that came with the kit. I got everything to work properly and I thought of things to do with the Arduino. While searching the internet I came to Pololu’s website and found this nice little Zumo kit. I thought it was very intersting and with the 12-12-12 discount also very attractive to give it a try.

The first step would be to make the Zumo drive on a Sumo ring on its own so I also ordered some reflectance sensors.

I started with:
Zumo robot kit, https://www.pololu.com/catalog/product/2505
2 Micro metal gearmotor HP 100:1, https://www.pololu.com/catalog/product/1101
2 QTR-1RC Reflectance sensors, https://www.pololu.com/catalog/product/959

I already had some LEDs, an Arduino Uno and some AA batteries lying around.

The build of the Zumo was pretty straight forward. Apart from me doing some silly things (messing up 5V and Ground on an LED and soldering a wrong jumper on the buzzer) the build was smooth. The User’s guide was very good and helpful in the process.

Adding the relectance sensors to the bot was a little harder. Soldering it in place as OK but the sensors where too far from the table to get good measurements and stay between the lines. I didn’t know that at first so I tried to get better results by adding an extra LED next to the sensor. This helped but was still pretty unaccurate.

I made a little bracket for the sensors and the extra LEDs. I don’t think these LEDs will be necessary now since the sensors are in a far better position now.

The programming bits where already done by Pololu (https://www.pololu.com/docs/0J57/7.b). I needed to adjust the program just a little to make it work for me. This was very easy to do because of the comments in the code.

(Minor) changes I’ve made to Pololu’s code:

  1. For debugging I added some serial prints to get track of the sensor values and lowered the speed of the motors.
  2. For normal use I needed to change the “<” marks to “>” marks on lines 74 and 83 since my surface is white with a black border while the Pololu code should be used for vice versa colors.
  3. Optimized the speed. A value of 300 seems to be a good point for me (with 100:1 gearing)
  4. Optimized reverse and turn duration. The FORWARD_SPEED, REVERSE_DURATION and TURN_DURATION in Pololu’s program don’t work by default so I changed the delay settings at lines 78, 80, 87 and 89 to do so.

My Zumo now works fine and stays on the plate (an old kitchen door really :smiley: ). Here’s a little video of it driving around. :sunglasses:

The Zumo is a very nice to start with and get used to the programming bits. Building the Zumo is easy and fun and the standard code by Pololu works great and is really helpful to get it running like mine does. I’ve had a lot of fun with the Zumo so far and I’d really recommend it! Also for newbies to robotics like me :sunglasses:

Future ideas for my Zumo:
Add an optical range finder (Sharp 10-80cm)
Make use of the built-in compass and accelerometers in the Zumo sield

In the end I’ll get the Zumo apart and use the parts to make myself an R2-D2 (from Star Wars). The nice shell is going to be 3D printed on my Ultimaker 3D printer. Still a long way to go from where I am now but at least there’s a plan :laughing:

Your project is coming along good. Stays inside the boundaries really
well. Much easier than you apparently thought it would be, LOL. I don’t
see why you would want to take it apart and use the parts for an R2D2.
You could design an R2D2 shell that would slip over the current Zumo,
convertible style.

It was way easier than I thought it would be to make it drive inside the boundaries! :slight_smile: I never thought I could be this far in the amount of time I spent on it even though I must admit Pololu did most of the work for me really…

R2D2 has two ‘legs’ in each of which I want to place a Zumo track. That means I need to get the motor + gear and the tracks apart from the Zumo chassis. I’ll bring the battery tray to the middle wheel of R2 to bring the c.o.g. down a bit. A lot of component will be in the dome of the robot so that adds relatively much weight there.