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Time for a little ROBOT WARS fun! Hands up if you’ve seen “Robot Wars” on TV? Hands up if you’ve ever wished you could be a part of Robot Wars, with your monster dealing out death and destruction to any other pile of nuts and bolts who dared cross your robot’s path . . . Well now you can! by Ross Tester THE SUMO MODULE W e can’t quite promise you the full-on Robot Wars experience with the jaws of death, power saws, fire and all those other enemy-killing devices (just how big a bank balance do you have?) but we can go close – for a lot less cost! With your Microbric Viper and the Sumo Pack, your robot can go into battle against other robots and, depending on how good your programming and control are, flip him/her/it over on its back, disabling it. You win! Besides, you don’t really want to totally destroy your mates’ robots, do you? OK, forget we asked. . . By the way, the Microbic Sumo Viper is an ideal first step if you do want to get into the real Robot Wars world of mayhem! What it does When fitted to your Microbric Viper 100  Silicon Chip (which incidentally needs the line tracker module also fitted), your Viper seeks out the opposition with a servocontrolled scoop which you have under your control to attack with. Your Viper knows to attack when the bump sensors at the front are activated. This triggers the program into turning the Viper into attack mode! We mentioned a moment ago that you will also need the ‘Line Tracker Expansion Pack’ (March 2006 SILICON CHIP). This is used to keep within the rules and detect the border of the Sumo ring so your Viper doesn’t drive over the edge. (Yes, there are rules in Robot Wars!). The Sumo ring is either a round white ring with a black border or, more popularly, a black ring with a white border. The former can be as simple as some black electrical tape forming a round border on a white surface, to a specially built, raised Sumo ring. Other designs The method of building and controlling the Sumo Viper in the instructions is just one way – there are, of course, many other ways and modifications to try. That’s one of the beauties of the Microbric system – experimentation. Just remember, though, if you depart from the suggested method, you’ll probably need to rewrite at least parts of the program to run it. But this is all part of the Microbric experience; learning how to write software to run your robots, so we are certainly not advising you against this. Just the opposite: we’re encouraging it! However, first up, we suggest that you do follow the suggested method of construction, get it working properly, then experiment with different siliconchip.com.au main punch-out boards, one with the base module plus lots of other bits, the second with the scoop and its “bits”. There will also be some fins, a pack containing a servo and actuators, plus some small plastic bags with a variety of hardware including plastic brics, nuts, bolts, spacers, etc. Assembly At left is the Sumo Expansion Pack (Dick Smith Electronics stores). You can tell it’s the Sumo Pack with the red dot against the Sumo description on the back panel of the pack. Otherwise all the packs look the same! configurations and programs to your heart’s content. You should find many ways to program the Microbric Sumo Viper to attack. For example, you could have the scoop continually lifting up and down rather than actuating just when the bump detectors actuate. Or you might put more bump detectors on the rear end so no-one can sneak up on you and attack you from behind. You’ll probably find many other Microbric enthusiasts around Australia (and further afield!) are doing exactly the same as you are, so why not jump onto one of the discussion groups on the ’net and compare notes! the servo off and saves power. By sending the Sumo module a [0], the servo stops trying to move to a position which means it can be rotated by external forces. To turn the servo back on, just send it another command. The Sumo Pack Many of the Microbric Expansion packs look the same but if you have a look at the back panel on the box, you’ll see a dot on one of the listed packs (see photos above ). Inside the box, you should find two Once again, detailed assembly instructions are available for the Sumo Pack on the ’net so we won’t waste space repeating them here. In essence, you assemble the scoop mechanism, mount the servo, construct the actuator arm and then attach the bump sensors. Construction follows the same simple method used throughout the Microbric series – all you need is a screwdriver. The control modules are preassembled so no soldering is re­quired. Don’t ignore the warning not to power up the Sumo module before calibrating the servo. The reason for this is that there is no way for the microprocessor to know what position the servo is set at when mounted, so it must be calibrated in the centre position. If you don’t do this, the very strong servo has enough power to break something – either itself of some other part of the Viper. And the whole idea is to disable someone else’s robot, not your own! Finally, you connect the Sumo module to your Microbric Viper. You’re now ready to unleash your Microbric SC Sumo Viper on your mates! How it works You should already be familiar with the bump sensors that come with the Viper and the bump sensors on the front of the Sumo module are no different. Controlling the position of the servo is pretty straightforward – you simply send a serial out command (Serout) stating the position you want the servo to be at (between 1 and 255) and the onboard microcontroller takes care of the rest; eg, Serout P6,i2400, [128] ; Sets the servo to the centre position through pin 6 There is a special setting that turns siliconchip.com.au Here’s what you should find in the Sumo Expansion Pack box: two large punchout PC boards, a servo and bags containing all the hardware you’ll need. April 2006  101