HexCrawler w/ Videos

The HexCrawler is a 6 legged robot with 2 degrees of freedom (legs move up and down and back and forth). It is built with heavy gauge aluminum, which is anodized a battleship grey color. This is the original HexCrawler, not the newer, grossly enlarged, improved design version. There was actually a revision prior to the current design that included redesigned legs that have better mounting for the servos. I purchased the hardware only kit of this version so that I could use my own, better built, servos. Notice the servo specs below on the S3. You have to ask yourself, “What were they thinking”, in the use of feather and micro servos. I’ve already had to replace both of them. Maybe they don’t like the 7.2 volts, but they don’t burn out, they wear out!

All in all, the HexCrawler (original design) is a good 6 legged robotics platform. It comes with a Basic Stamp 2, Board of Education, and Mini SSC’s. There’s plenty of room to add breadboards, co-processors, and sensors galore. You’ll notice wires at the front of the Crawler. These are for regulated 5V, Battery voltage, and ground. The servos could be a bit beefier and there were problems with the Dubro ball links and threaded rods (they had to be glued to stay together), and the supplied code just plain didn’t work but after all the quirks were ironed out, the Crawler does a good job of meandering around the house. The code needs a bunch of tweaking and the legs need to be software aligned so that the Crawler walks straight.

HexCrawler w/ Videos

The BOE is a Revision B (Doesn’t have on/off switch) and it contains a mod that I do to all my BOE’s prior to Revision C. The Vdd (5 volt) trace to the AppMod header from the Stamp is cut and 5 volts is routed to the AppMod header from the regulator. This is another one of those “What were they thinking” questions, since the Basic Stamp can only supply 48mA of current. Pic of the trace cut here.

The original bulleted features for the HexCrawler appear below:

• Audience: Advanced Robot Enthusiasts

• Power Supply: 9V Battery, and 6 cell battery pack (not included). When properly tuned, the HexCrawler can walk up to an hour of continuous use before a recharge of a 3000 series Ni-MH battery.

• Assembly Tools: Angled cutters, small Phillips screwdriver, and 1/4” wrench (not included)

• Time Required to Build and Program: 6.0 hours – The HexCrawler’s 100 page manual guides you through the assembly process step by step and includes 8 sample source code programs to get you off the ground.

• Chassis Dimensions: Main body is 13″ long, 8″ wide, and 6″ tall. Overall dimensions with complete legs are 13″ x 14.5″ (leg to leg).

• Height: 6″ standing, 4.86″ squatting • Ground Clearance: The HexCrawler’s legs are fully adjustable. Each leg offers 2 fulcrum points to choose from in the event your HexCrawler needs to carry extra heavy loads. Each leg can also be extended for greater ground clearance (from 3″ to 4.75″).

• Leg Movement: 2 degrees of freedom (vertical and horizontal)

• Weight: Total kit is 4.2 lbs with servos and electronics (no battery pack)

• Payload Capacity: 7.5 pounds • Chassis Material: Super strong .063 Gauge 5052 aluminum with type II anodizing for weather and scratch resistance. CrustCrawler machines the aluminum within 1/100″ tolerance values, using state of the art drill and punch machines. During the anodizing process, the machined parts are “bright dipped” to give them a bright sheen and then type II anodized to the specified color. Type II anodizing indicates the type of hard finish that is applied during the the anodizing process to prevent scratches and weathering to the finished product. Type II is one of the hardest non-military specification anodizing processes that can be applied to a commercial product.

• Object Detection: Purchase additional accessories and connect them to the HexCrawler. Sold Separately. • Customization: Over 155 sq. inches of total prototyping space is available on the HexCrawler body.

• Programming Specifications: The HexCrawler program contains 3 fully adjustable walking gaits in just one program! All programs are completely configurable through an easy to use interface or programmatically depending on your application. The code is considered RF ready, just substitute the switch with the RF package of your choice and you are now wireless! 1 Ripple forward and backward: This gate resembles that of a bug similar to a genghis gait 2 Tripod forward and backward: Three legs move at once forming a tripod resulting in a very balanced smooth stride. 3 Turning: The robot can turn in place left and right, literally.

• Expandability: Breadboard or through-hole AppMod will connect easily to the AppMod header. Expandability is possible with the following add-ons (not included): SRF04 Ultrasonic Range Finder, SSIR Detectors, Compass AppMod, RF modules, and accessories from CrustCrawler. and for the S3, Sensor Scanning kit (note the severely underpowered servos)

DESCRIPTION: The S3 is a fully adjustable tilt pan system allowing you to attach sensors and cameras of all shapes and sizes. The Sensor Scanning System can be attached to your robot platform at any angle without effecting its panning capabilities. Rock solid design eliminates any excess sensor shake or instability during operation. This system can pan and tilt horizontally and vertically to 180 degrees. The kit includes the following parts:

• (1) Sensor Scanning System Hardware Kit

• (1) HiTec HS-55 Feather servo • (1) HiTec HS-85BB Mighty Micro servo

• (2) HiTec 18″ Heavy Duty Servo Extension Wires • (1) S3 Construction Manual The S3 system has been custom designed to fit onto the front support bracket or the front, top deck of the HexCrawler. However, the back and lower plate have expansion slots that will accommodate virtually any other robotic platform you currently may be using.

Videos:

Wandering HexCrawler Video clip showing the HexCrawler walking about in the yard. You’ll probably notice that it doesn’t walk straight. The servos are aligned mechanically as much as possible – they now need to be adjusted in software to accommodate the differences in center (home) position.

Obstacle Avoider Video clip showing the HexCrawler avoiding obstacles using the SRF-04 Ultrasonic Ranger mounted on the S3 Sensor Scanner. The code used needs some tweaking for distance and to add panning back and forth while walking.