Home Products How-to Shopping Cart FAQ About Us Contact Us Affiliates

Follow FingerTech_Bots on Twitter
Find FingerTech Robotics on Facebook

Login Status  Login Status

Not logged in

» Login

Shopping cart  Shopping cart
0 Product(s) in cart
Total 0.00 CAD
» Checkout

Customer Map
Customer Map

Mailing List

Solution Graphics
0 Product(s) in cart |
Total 0.00 CAD |

Home » Categories » Robot Kits

FingerTech 'Cobra' Mini-Sumo Chassis
FingerTech 'Cobra' Mini-Sumo Chassis
  • Description
  • Control Boards
  • Videos
  • CAD Files
  • Reviews
  • Related
• 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 4WD Gold Spark motors, four high-traction mini-sumo wheels, two on-board motor controllers, three QTI line sensors, stainless steel scoop, heavy steel ballast, screws, wrenches, and stand-offs for mounting your control board!

• The Cobra now includes two on-board motor controllers, three QTI analog/digital line sensors, and a bright blue LED power indicator.
• Special introductory price - may go up at any time!

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:
PCB Chassis: The Cobra baseplate is a circuit board that has mounting holes for the scoop, ballast and standoffs.  The newest revision includes on-board motor controllers, QTI line sensors (two front, one rear), and a bright blue LED power indicator.
Motors: Four 50:1 Gold Spark Gearmotors are epoxied and soldered in place.
Motor Control: The Cobra has two on-board motor drivers (left and right). To operate them, you will need to connect their DIR (direction) and PWM (speed) pins to a microcontroller. For DIR, 5V is forward direction and 0V is reverse. The PWM pins require a 5V pulse-width-modulated waveform for smooth operation.
Wheels: Four FingerTech Mini-Sumo Wheels.  Shore A20 polyurethane - the highest traction mini-sumo wheels available.
Line Sensors: Includes three QRD1114 line sensors (2 front, 1 rear) wired into QTI configuration for digital or analog operation. Three headers connect to your control board. A circuit diagram is printed on the 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.  Four washers for spacing ballast fro
Two hex wrenches included for tightening screws and setscrews.
Instructions: Full-color assembly steps, wiring diagram, header pinouts, and sensor/motor controller instructions. Cobra_instructions_R2.pdf

Battery: The chassis has a spot to accomodate a 44x24x29mm (1.75x0.93x1.15") battery.  Our Rhino 11.1V 360mAh or Nanotech 11.1V 180mAh fit perfectly and will run the robot for dozens of matches.  Min/Max Voltage: 6V-16V.
Electronics: In the chassis kit, the brains are up to you.  We carry the user-friendly Arduino Uno's, but boards from the SumoVore, Mark III, or SumoBot will all work.  Use the PCB Mount Kit to fit boards 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.

Orders normally ship within 1-2 days.  Other Gold Spark motor ratios can be used for an additional $10 fee - 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!)
You can use a variety of boards to control your Cobra chassis. We have begun writing sample code for different systems. Coming up are Arduino, Parallax, Mark III, and Sumovore.

Parallax SumoBot Board

PIN 13 to Left motor PWM pin
PIN 12 to Right motor PWM pin
PIN 6 to Left motor DIR pin
PIN 5 to Right motor DIR pin

PIN 10 to Left line sensor power (W)
PIN 9 to Left line sensor input (R)
PIN 7 to Right line sensor power (W)
PIN 8 to Right line sensor input (R)
(Both line sensor B lines tie to Vss)

PIN 4 to Left IR LED output
PIN 11 to Left IR sensor input
PIN 15 to Right IR LED output
PIN 14 to Right IR sensor

PIN 1 to Piezo speaker (other side to VSS)
PIN 0 to StartLED (other side to 470R to VSS)
PIN 2 to added RightLED (optional - for displaying which sensor sees opponent)

Cobra GND to SumoBot Board VSS
Cobra VIN to SumoBot Board servo power (the middle pin from either of the two servo connector headers) - this allows you to turn the switch to position 1 and program/test without powering the motors.  Position 2 adds power to the motors.
Battery wired to SumoBot board.  Battery connector on Cobra unused.

Sample Code: SumoBot - Cobra V2 Basic Competition Program 1.0.bs2

Arduino Uno
While we work on full instructions, here is a quick code sample to get your motors driving!

Right PWM to pin 3
Right DIR to pin 4
Left PWM to pin 5
Left DIR to pin 6
Cobra GND to SumoBot Board VSS
Cobra VIN to SumoBot Board servo power (the middle pin from either of the two servo connector headers) - this allows you to turn the switch to position 1 and program/test without powering the motors.  Position 2 adds power to the motors.
Battery wired to SumoBot board.  Battery connector on Cobra unused.

Sample Code:
// Arduino Motor Control - sweeps both motors back and forth
int sweep = 255;
int dir = 1;
//Pin hookups:
int PWMR = 3;  // use analogWrite(PWMR,val) to control the Right motor speed
int DIRR = 4;  // use DigitalWrite(DIRR,val) to control the Right motor direction
int PWML = 5;  // use analogWrite(PWML,val) to control the Left motor speed
int DIRL = 6;  // use DigitalWrite(DIRL,val) to control the Left motor direction

void setup() {
  pinMode(PWMR, OUTPUT);   // sets the pin as output
  pinMode(PWML, OUTPUT);   // sets the pin as output
  pinMode(DIRR, OUTPUT);   // sets the pin as output
  pinMode(DIRL, OUTPUT);   // sets the pin as output

void loop() {
  for(sweep = 255; sweep >= 30; sweep -= 20) {
  digitalWrite(DIRR, dir);  // R motor direction forward
  digitalWrite(DIRL, dir);  // L motor direction forward
  analogWrite(PWMR, sweep);    // R motor speed
  analogWrite(PWML, sweep);    // L motor speed
  if(dir==0) dir=1; else dir=0;    // change motor direction

Here is a quick video showing the top speed using 50:1 Spark motors at 11.1V.
8 Product Reviews - Average rating 4.9 / 5 (Show All)

Click to review this product

First Robot Build

- 20th October 2015

This is a great product and they give great support. I was making a simply mistake wiring my Mini-Sumo Chassis for a combat robot with their Tiny ESC and Tiny Mixer but within a couple hours of me emailing asking them about it I had a friendly and fully informative response of how to fix it. I will definitely be ordering more items from them for future combat robot builds. The shipping speed is excellent with me living in the United States and them being based out of Canada. Most of my packages where received within a week of ordering.

Cobra - mini sumo robot

- 25th February 2015

The FingerTech Cobra is one of the best sumo robot chassis we have tested. Being a robot competitor itself, FingerTech knows what is needed for such a robot.


- 25th February 2015

A great kit. Goes together in literally like 2 minutes. Super high quality. I preordered the version with built in motor drivers and it was definitely worth the wait. Now my kids want one.


- 15th July 2014

It arrived completely perfect, and I'm very impressed by this chassis. The on-board circuitry helps a lot, and the motors are really powerful. Cannot wait to test it in a competition!


- 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

- 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]

Click to review this product

Kingduino Uno R3Kingduino Uno R3 - 19.05 CAD
• Give your robot a brain!  The Kingduino Uno is an excellent control board for the Cobra Mini-Sumo Kit.
• Interfaces easily with a myriad of sensors.
• Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.
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) - 22.05 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 and injection-molded hubs.
• Since September 2014, the setscrew is changed from 4-40 to 6-32. Now uses 1/16" hex wrench.
Nano-Tech 3S (11.1V) High-Discharge Lipoly PackNano-Tech 3S (11.1V) High-Discharge Lipoly Pack - 13.22 CAD
• High-discharge packs - Get the most from your batteries!  A higher C rating allows you to pull a higher current from the same sized pack!
• High quality silicone-insulated wire for high current applications.
• Five capacities of: 180, 350, 370, 460, and 950mAh.
Rhino 3S (11.1V) 20C/30C Lipoly PackRhino 3S (11.1V) 20C/30C Lipoly Pack - 12.15 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.
Ask A Question
List Price: 210.97 CAD
Price: 138.10 CAD
103.47 USD 97.80 EUR
Valid XHTML 1.0 Transitional
Home - Products - How-To - Shopping Cart - FAQ - About Us - Contact Us - Affiliates
Client Login - Terms & Conditions - Privacy Policy - Site Map