Sumo

Flippt · Post by **Flippt** » Tue Nov 13, 2007 3:41 pm

Just for the record I got a project at school which involves doing a Sumo robot which will compete in the Swedish Championship later in April next year.

We are going for Standard weight class (3kg 20x20cm) and with 1 sonar, 3 edge senors and 2 motors with alot of torque (dont know brand or name).

(Current looks. this is just the test plate to see if the edge sensor and sonar works)

At the moment we got problems with detection. It does see an object and goes for it, but when the object is out of "sight" it dosent know what to do next. Currently we set it to turn around and look, but this can bring the oppenent to a easy victory, and we use all the timers thats avaible on the AtMega16l chip so we got no more room for another sonar or such.

peterwaller · Post by **peterwaller** » Tue Nov 13, 2007 8:52 pm

If you look on the Daventech site they have an ultrasonic range finder that has it own built in timer see (SRF10).
http://www.robot-electronics.co.uk/shop ... rs1999.htm
This is controlled over I2C bus which I believe, but you had better check, is the same thing as the SPI interface provided on you processor. I have never used this but I am sure the data sheet will cover it.

Post by **BeligerAnt** » Tue Nov 13, 2007 9:31 pm

I2C is completely different to SPI !!!

SPI uses 4 wires: clock, data out, data in, chip select. It needs a separate chip select for each peripheral, so it's often more than 4 wires!
I2C uses only 2 wires: clock and data. The data line is bidirectional. Both lines are open-drain outputs and in fact the clock is also bidirectional (sort of).

However, all is not lost. I2C is a Philips (now NXP) trademark and licenced bus protocol. Atmel aviod all the licencing and royalties by calling their version TWI (Two Wire Interface). I think most of the ATMega processors have a TWI interface.

If you don't have one built in, you can do it by manually toggling two I/O port bits. It only runs at 100kHz so it's not usually too bad for a small processor.

If you are running out of timers, consider using software timers for some things. Set up a hardware timer to give a regular interrupt then use software counters to count the interrupts. Each counter can be easily started, stopped, enabled, disabled under software control.

peterwaller · Post by **peterwaller** » Wed Nov 14, 2007 8:24 am

Another senior moment I remember looking at these devices some time back and checking that my processor could talk to them but not how. The ATMEGA16L does support TWI.

Flippt · Post by **Flippt** » Tue Jun 03, 2008 11:09 pm

Just wanted to give you an update on the build.
Som changes since last post; Instead of using 2 motors as we could use 4, two on each H-bridge (A3953sb), so more pushing power, and two 3000mAh NICD pack at 14.4V.
In the end it weighted at totalt 1,9Kg, so we could have put on some more weight

We did attend at the Swedish Championship, but did not do really well. One of the relfex detectors broke during the competition and we ended up in a loop..
We did have problems with using brake and make the motors stop for 5 seconds without making the H-bridges smoking hot. Any help with this would be helpful!

Anyway, I did get an agreement with my school and I get to keep the project! All the parts and motors for free, which is nice as the motors alone costs about ?50 each as new!
Pictures (without battery):

Flippt · Post by **Flippt** » Sun Apr 19, 2009 8:26 pm

Just reviving old thread:

On May 10th, Swedish championship of Robotics is being held in Gotenburg. It's gonna be 3Kg sumo, 500g Sumo and 5 different obstical courses.
Last year, me and a classmate went to this event and got our asses kicked. But now I'll try and see if I can do any better. The robot is the same, but some minor changes in the program.

for more information;
www.robotsm.se

slurp · Post by **slurp** » Mon Apr 20, 2009 4:34 pm

Good luck!

regard,
Colin