Author Topic: anybody w sumo experiance read pls  (Read 2561 times)

0 Members and 1 Guest are viewing this topic.

Offline frank26080115Topic starter

  • Supreme Robot
  • *****
  • Posts: 322
  • Helpful? 2
anybody w sumo experiance read pls
« on: November 07, 2007, 10:29:59 PM »
I have this black construction paper, it is almost as IR reflective as white printer paper, but i also have this black  object and it is half as reflective, my naked eye can't tell which is more reflective, how sensitive does my sensor need to be for a sumo ring?

Offline bulkhead

  • Full Member
  • ***
  • Posts: 102
  • Helpful? 0
Re: anybody w sumo experiance read pls
« Reply #1 on: November 08, 2007, 02:36:34 AM »
I have some experience.  I just use the QRD1114 sensors because they are cheap and they work pretty well.  I have a constant in my program so I can adjust the threshold (line/no line) depending on the ring.  Usually it's pretty evident when a dark surface becomes white; the fine tuning of the constant helps for getting the brown start lines to not trigger the 'line detected' routine.  I have never actually been to a real sumo competition so I don't know if you can test your robot beforehand or not...

Offline JonHylands

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 562
  • Helpful? 3
  • Robot Builder/ Software Developer
    • Jon's Place
Re: anybody w sumo experiance read pls
« Reply #2 on: November 08, 2007, 07:51:14 AM »
Generally you can test your robot on the ring beforehand. I have a "debug menu" that runs over the serial port. When I power up the robot, if I'm pushing the start button it drops into the debug menu instead of starting the sumo code. I hook the robot up via a USB -> TTL converter, and run HyperTerminal.

I can test my motors, range finders, edge sensors, plus set all the timing constants and thresholds (which are all stored in EEPROM) from the debug menu. The menu prints out as text, and I can hit specific keys on the keyboard (indicated in the menu) to execute each entry.

Since Seeker 2 runs off a finite state machine, it also uses the rest of EEPROM as a state log, which I can view/reset from the debug menu. Basically a debugging aid, it shows a list of the states the FSM went through on the last run.

- Jon

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,703
  • Helpful? 173
    • Society of Robots
Re: anybody w sumo experiance read pls
« Reply #3 on: November 08, 2007, 07:57:53 AM »
I don't even sense the line with my bot as it employs a completely different strategy (my Stampy bot) . . .

But I still have a lot of experience with line following for another competition . . .

Anyway, there are different ways to detect the line. The most straight forward way is as bulkhead does and fine tunes a threshold.

A slightly better way would be to place your sumo on the competition board and push a button for it to record sensor values. Then put it on the white line to record another set of sensor values, and push the button again. Then it will sum those values and divide by two, automatically setting a custom threshold. I call it auto-config because it works on any playing field with no manual tweaking. Push the button one last time for the bot to enter into kill mode using that auto-config value :P

Another way doesn't even use a threshold . . . monitor your sensors for a value change spike. For example, if your sensor ADC value changes say 20 points in a fraction of a second, that means it crossed the line. Basically subtract old values from new values, and if the sum is high, your robot has crossed the line.

Offline Monk

  • Beginner
  • *
  • Posts: 2
  • Helpful? 0
Re: anybody w sumo experiance read pls
« Reply #4 on: November 09, 2007, 03:14:44 PM »
I also use QRD1114, but I use a op-amp as comparator to make its output digital.
Then, the threshold is set by a voltage divider(potentiometer).

Just like this
http://www.markallen.com/teaching/images/electronics/comparator.jpg

Vinput is the sensor data
R2 and R3 are the potentiometer
Vout goes to a digital pin of the microcontroller.

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,703
  • Helpful? 173
    • Society of Robots
Re: anybody w sumo experiance read pls
« Reply #5 on: November 09, 2007, 03:32:46 PM »
The problem with the pot idea is that it requires manual tweaking, forcing you to retweak if someone changes the sumo board or clouds changing the lighting coming into the room through a window.

I used to do the manual tweaking and it gave me millions of headaches . . .

Offline Monk

  • Beginner
  • *
  • Posts: 2
  • Helpful? 0
Re: anybody w sumo experiance read pls
« Reply #6 on: November 10, 2007, 12:48:31 AM »
The main reason I used it was because I didn?t have any analog inputs lefts.

But in the last competition it was easy for me to set the threshold by a pot, easier and faster than if I have to tweak by software constant.

But the ideias of the auto-config and monitor sensors fors spikes on readings are very good. The latter maybe good for distance sensors too.

 


Get Your Ad Here