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Home » Categories » Robot Kits

FingerTech 'Cobra' Mini-Sumo Chassis
FingerTech 'Cobra' Mini-Sumo Chassis
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• Designed to be a competitive entry into the masters class of mini-sumo, this chassis has the ability to beat those big-wheeled servo bots every single time.
• Includes garolite chassis, steel chassis ballast, 4x Spark motors, polyurethane mini-sumo wheels, line sensors, circuit board stand-offs & screws, and a stainless steel scoop.

The Cobra conforms to the mini-sumo ruleset of RoboGames, the world's largest robot competition.  Most events uses these rules, but always check with your event organizer to make sure.
Width: 9.9cm (3.90")
Length: 9.75cm (3.84")
Height (ground to top of standoff): 3.77cm (1.48")
Weight: 333grams (11.75oz) - Maximum allowed in competition is 500g (17.63oz)

Kit Includes:
Chassis: 1/16" thick garolite baseplate (pic). Has mounting holes for scoop, standoffs, and QRD1114 floor sensors (2 front, 1 rear).
Motors: 4x 50:1 Gold Spark Gearmotors
Wheels: 4x 1.125" mini-sumo wheels.  Shore A20 polyurethane - the highest traction mini-sumo wheels available.
Sensors: Includes three QRD1114 floor sensors (2 front, 1 rear) wired into QTI configuration. 3-wire cables connect to your pcb.
Scoop: 0.020" stainless steel angled scoop (can be legally sharpened to 0.010")
Steel Ballast: An underweight mini-sumo is at a disadvantage!  This steel ballast keeps the center of gravity low.
Screws: Four 6-32x0.375" screws for mounting the scoop, ballast and stand-offs.  Four for securing circuit board to standoffs.
Two hex wrenches included for tightening screws and setscrews.

Battery: The chassis has a spot to accomodate a 26x53x26mm (2x1x1") battery.  Our Nanotech 11.1V 180mAh fits perfectly and will run the robot for dozens of matches.  Some Velcro will secure it in place.
Electronics: In the chassis kit, the brains are up to you.  Boards from the SumoVore, Mark III, SumoBot or even an Arduino all work!  Use the PCB Mount Kit to fit board with different hole patterns.
Sensors: Opponent detection can be anything you desire.  Infrared emitters/sensors are most common, but ultrasonic sensors are an option too.
Motor drivers: If your "brain" does not include motor drivers, two tinyESCs can be used (1 per side).  They are very small and can be controlled using simple Servo PWM - only one data line each is required!

Orders normally ship within 1-2 days.  Other Gold Spark motor ratios can be used - please add a note in the checkout comments. (35:1 is the most commonly used after the default 50:1, but make sure your sensors can react fast enough to the increased speed!)

Here is a quick video showing the top speed using 50:1 Spark motors at 11.1V.
4 Product Reviews - Average rating 4.8 / 5 (Show All)

Click to review this product


Jean Carlo - 21st March 2014

I tested every motor with an H Bridge and very closed delays and they respond extremely nice. Everything came in order except for one thing,one motor wasn't well pasted and came hanging in the bag, but after a quick fix everything was in order. [FT: we now ship differently!]
Very nice product :D I'm using this for a competition, just looking for some nice sharp sensors, good servos and already making my hand made aluminum body. 4.6/5

Very good design, but not very well protected in the package

Rubén Espino - 30th April 2012

That's a very good design. I like the ballast, wheels and motors. But the chassis didn't come well packaged because a motor was unstuck when it arrived at my home. [We have listened and now pack the Cobra's differently. Thanks! -FingerTech]

Superb Machine!

iankantian - 06th March 2012

The description doesn't do it justice. The ballast is BELOW the garolite chassis for a mighty low center of gravity. The force required to push it side-ways on my desk while parked easily exceeded 1 kgf, so the tyres are pure magic at gripping smooth surfaces. When it hits my older sumo-bot the Cobra simply plows it out of the way like it wasn't even there! Impressive!

Great starter and competition kit

RoboSlave.Blogspot.com - 24th February 2012

I have been very impressed with this kit and can't wait to get it into a competition. See images and project details at RoboSlave.Blogspot.com

Click to review this product

FingerTech 'Cobra' PCB Mount KitFingerTech 'Cobra' PCB Mount Kit - 5.95 CAD
• Using the Cobra chassis with an existing circuit board?  You'll need a good way to mount that PCB!
• This PCB Mounting Kit makes easy work of boards with different hole layouts.
FingerTech Mini-Sumo Wheels (pair)FingerTech Mini-Sumo Wheels (pair) - 19.05 CAD
• Want to be at the top of the minisumo class but your robot's wheels keep slipping?  Look no further!

• Top-quality competition wheels made from high-traction polyurethane.
FingerTech tinyESC v2FingerTech tinyESC v2 - 34.29 CAD
FingerTech tinyESCs pack the most power into the smallest package!  Don't sacrifice space and weight on bulky motor controllers - tinyESCs are what the champions use!
Version 2.3 now with 50% higher continuous-current capacity!  Thicker pcb traces shunt heat away from the driver chip faster - meaning you can run larger motors!

• Bi-directional brushed motor controller.
• Ultra-compact and lightweight.
• Undervoltage, overcurrent, overtemp protection.
• Internal BEC (battery eliminator circuit) provides 5V to receiver - no extra receiver battery required!
• Calibrate function allows precision driving.
• Status LEDs for both directions and calibration.
• Read the tinyESC review in SERVO Magazine!

These speed controllers are perfectly matched to our own line of Gold Spark and Silver Spark motors, Copals, Sanyos, B16s, B62s, 1000RPM eBay specials, etc.  For the short operating times of robots, anything up to 5A stall can be run by tinyESCs.
Rhino 3S (11.1V) 20C/30C Lipoly PackRhino 3S (11.1V) 20C/30C Lipoly Pack - 10.94 CAD
• Rating: 20C Discharge, 30C Burst
• JST connector, JST-XH balance plug, and high quality 18 gauge wire.
• Capacities of: 360, 460, 610 and 750mAh.
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List Price: 125.80 CAD
Price: 119.04 CAD
108.31 USD 78.47 EUR

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