Stiquito Robot Kit     Table of Contents

     

     
 

 

 

 

 

 

 

 

 

 

 

 

Stiquito is a small, inexpensive hexapod (six-legged) robot. The robot is unique not only for it's inexpensive price, but also for the unlimited applications it can be used for. The Stiquito has been used by universities, high schools, hobbyists. In the early 1990s, Jonathan Mills set out to design the Stiquito because he needed a robotic platform on which to test his research on analog logic. In 1992, Mills made available a small, inexpensive robot for $10, which by 1996 received orders for over 3000 robot kits.

There are many different types of robots. The classic robots depicted in science fiction books, movies, and television shows are usually walking, talking, human-type devices. Of the many types of robots in use today, one of the most practical robots are the mechanical arms used in the manufacturing industry. These robots are able to carry out repetitive, dangerous jobs with accurate results each time. In addition, unlike human labor, robots don't need coffee breaks, holiday pay, retirement, etc. Another type of robot used in industry is the autonomous wheeled robot. They followed an embedded signal in the floor.

  Stiquito Design The Stiquito robot is intended to provide a low cost, hobbyist robot, with large capability. For propulsion of the simplest configuration, nitrinol (specifically, Flexinol from Dynalloy, Inc.). The Flexinol is an alloy of nickel and titanium that contracts when heated. It is also known as shape memory alloy. The robot walks when the heated nitrinol actuator wires attached to the legs contract. The heat is generated by passing current through the nitrinol wire. This material provides a muscle-like reaction for the circuitry, and would closely mimic biological action. For the counterforce to the nitrinol, music wire is used. The wire serves as a reaction force to stretch the nitrinol back to its original length and provide support for the robot. For the body and controller of the robot, a 0.125 inch plastic rod is used. The plastic is used because of its ease of cutting, drill and glue. It also has relatively good heat resistance characteristics. For the robot legs, body support, and nitrinol attachments, aluminum tubing is used. The robot is six-legged and is 75 millimeters long, 70 millimeters wide, 25 millimeters high and weighs 10 grams. It is constructed of fewer than 40 parts, 12 of which are moving.   Construction Material For assembly of the robot, most construction material is found in the kit delivered with the instruction booklet. In the kit, there are the following materials for construction:  
ST-100 Body 600mm Nitrinol (Flexinol)
ST-101 Controller 70mm Bus Wire
100mm Aluminum Tubing 600mm 20 AWG Wirewrap
9V Terminal 320g Sandpaper
600g Sandpaper 1500mm 34 AWG Mag Wire
100mm Music Wire
  In addition to these materials, various tools are also needed. For the common hobbyist, these tools are commonly used in constructing such projects as airplanes, cars, boats, etc. These materials are as follows:  
Needlenose Pliers Small Knife
Wire Cutters Ruler graded in millimeters
Voltmeter Two AA Batteries and Holder
  As stated before, the assembly of the Stiquito requires hobby-kit-building skills. Practice the skills needed to build the Stiquito before assembling the robot, using plastic scrap and thin wire. The kit comes with additional material in case of mistakes, but there is not enough to practice with. Measuring Following the well known saying, "Measure twice, cut once" will reduce mistakes in all cases. Use a graded ruler with millimeter measurements. Cutting Before cutting check to make sure your fingers or other pieces are not in the way of the knife. Cut away from the body to avoid injury and make small cuts to avoid removing too much or making too deep or too large of a cut. Deburring In most cases, sawing and cutting will use rough edges, or burrs, on some parts. Use the sandpaper to remove the burrs and rough edges. First trim the burr with a knife and then finely sand the remaining burr with sandpaper. Leaving burrs on parts, especially crimps, can cause the Flexinol to break. Parts that are press-fitted can bend or break during assembly if not deburred. Sanding The end of the aluminum tubing should be sanded with the fine (320-grit) paper. Flexinol and music wire should be sanded by the ultra-fine paper (600-grit). Sand the wire after it has been bent or knotted to avoid it from breaking. Sanding wire too much will weaken it enough to break during assembly. Knotting & Crimping Flexinol is similar to stainless steel. The 0.004 inch nitrinol wire we used can be knotted without breaking as long as the wire is not too tight. Crimping and knotting the wire was found to be the most reliable way to attach the nitrinol. In construction of the robot, the nitrinol is knotted for support in the legs. When the nitrinol is attached to the legs, crimps are used to secure the tightness of the flexinol. The knot gives the crimp something to hold on to.This contruction procedure is described i nthe book.   Advanced Programming Advanced Stiquito robot configurations can, and in many cases, must be controlled by computer using parallel interface. These advanced robots have 10 or 12 actuators, too many to control manually. To use a PC-based controller, the interface is attached to a parallel printer port on an IBM PC or compatible computer. Programming language that can be used for this interface can be QUICKBASIC, BASIC and even such software as GWBASIC. To make the interface cable, parts and utensils are listed with detailed instructions in the Stiquito Manual.

Another method of control is an autonomous controller, based on the Motorola M68HC11 micro-controller. This controller was designed to control the walking type-motion of the Stiquito. Using the micro-controller allows you to receive and decode commands from an infrared transmitter and also allows you to take appropriate control action for the hexapod robot to move. Advantages to using the micro-controller are listed below.

 Complete programming and wiring of complex circuitry for the Stiquito can be found in the robot manual.