Smash 'n Dash

I saw a video clip of a mini sumo bot a while ago and set out on a mission to build one for my 5 year old son. Being my first robot, it turned out to be quite a challange and after a lot of struggling and tons of fun it's finally working.

I started with the circuit design which basically consists of the following:

1 x 18f2550 loaded with a modified usb boot loader

2 x L293D motor controllers, piggy backed to handle the load

2 x CNY70 optical sensors to detect the line

2 x IR Led and IR remote reciever to detect the opponent.

I couldn't figure out how to generate the 38khz signal required for the reciever seen as the pwm ports where being used to control the motors so I ended up using a 555 timer to generate the 38khz carrier with the processor enabling and disabling the 555 in order to generate the IR bursts.

My next step was to design the board using the free version of Eagle CAD and one of my work colleagues etched the board using a homemade UV box and ferric chloride.

I used Sketchup to design the template for my chassis and made it out of an old piece of sheet steel I found lying around.

Sourcing decent motors turned out to be an issue due to financial and logistical constraints and I ended up using an old Tamiya gearbox which my work colleague generously donated to the project. Thanks Charles!

The code uses a simple FSM. There are 3 states - Hunt, Attack & Survive. I compiled the code using MPLAB IDE v8.88 and the C18 compiler.

All in all I'm pretty happy with the outcome, the dimensions don't conform 100% to the mini sumo rules (this was mainly due to the size of the gearbox and the width of the wheels) but there aren't any mini sumo competitions in my country so it's not an issue.

Anyways, thanks for taking a look at my project. I'll post a video soon.