Servo - January 2007

FIGURE 4. Everything is nearly mounted.

the finished mounts ready for use.

Finishing Touches

With the motor mounts complete and sides cut out, all I had left to do on the base plate was to cut out the holes for the wheels, which I did using a plasma cutter. With each subcomponent complete, it was time to combine them. I decided to use 10-24 size screws to fasten it together. The motors were mounted, the sides were attached to the base plate, and the electronics shock mounted. Shock mounting is always critical for electrical components. As you can see in Figure 6, the speed controllers and relay board were shock mounted to an 1/8” sheet of polycarbonate, which was then shock mounted to the frame. The batteries must always be easily accessible; to meet this requirement, I chose to use Velcro straps to secure them.

At this point, as you can see in Figure 4 the robot was missing the front half. For this, I chose a wedge to allow me to gain control of other robots to help me use my hammer to its full effect. After choosing an angle, I made the wedge and attached it using the same methods as the rest of the frame. Figure 5

FIGURE 5. The wedge is completed and attached.

shows the robot nearly done!

Everything was complete except for the top armor, the hammer, and the wiring. I made the top armor out of .09 inch carbon fiber sheet for its strength and minimal weight. For this, I used a diamond wet saw, the key word being wet. Carbon fiber dust can be extremely harmful and should not be breathed in under any circumstances.

Through a combination of having water constantly pumping onto the cutting edge to eliminate dust and a respirator, I was able to easily and safely cut the top plate. The hammer was more fun, for this I found a piece of 1/8” steel and used the plasma cutter to create the hammer shape I was looking for. To attach the hammer to the drill, I took advantage of the threaded shaft, clamping the hammer arm between the shoulder of the shaft and a tightened nut. The nut and threaded shaft then had an 1/8” hole that a pin went into to keep the nut from backing off. With everything mounted and ready to go, I wired the robot up using primarily 14 gauge wire. Figure 6 shows Gone Postal at the event ready for battle.

Conclusion

Overall, Gone Postal has under-

FIGURE 6. Gone

Postal prepped and ready for battle!

gone four iterations since it was first built, gaining spring steel armor over the side UHMW and a titanium wedge and hammer arm. In each iteration, it has become a little smaller and a little tougher, but the same core building techniques have been used each time.

Figure 7 shows Gone Postal in its prime. It is ranked historically in 30th place out of over 250 robots, racking up a 35 fight record and known to many as the bot that just won’t die. It has proved to be one of the most fun bots I have built and competed with, being cheap, effective, and different. Further details on Gone Postal including photos and videos can be found at www.robotic-hobbies.com. SV