1.4 Construction of the Chassis


OK then, Time to construct the chassis of our 'bot (or "body", if you will).


The chassis is mainly constructed of of wood. The only non-wood parts are the motor brackets, and the castor (depending on the type you use or how you build your own). Many people become surprised about the use of wood because it may not sound or seem "robotic" enough. Infact for the majority of the robots I have ever built/seen consisted of some wooden part of the body (if not the whole body itself).


Ok, first, lets observe the design of the chassis. I wanted to create something with a simple, yet efficient design that will allow easy contruction and accessibility to any features added. A circle was too complex, a rectangle too bulky, but the trangle would not look very sturdy, nor decent, aswell as there isn't enough space to create a modify-able platform. Instead, I used the rectangle design, but tapered it off to form a sort of trapezoid in the end of the robot. The design consists of the assembly of very few pieces: one wooden body piece, 2 motor brackets with the motors, and the castor. In total, without the castor, the chassis is 13.7cm long (have you figured out why I called this the MICRO RC Surveillance Robot?) It is 8.8cm wide. At the tapered end, it is about 3cm wide. The tapered portion is 4cm long. It is about .5cm thick.


General Template of robot chassis


The first part with the custruction of the robot is to trace out the chassis on a piece of wood. I chose to use plywood, which is many thinner layers of wood glued together to form a single, lightweight, strong, yet cost efficient piece of wood.

Once you traced it out, feel free to cut through the template using a basic hacksaw, or even a rotary hand tool. Smooth out the edges with sand paper or a rotary hand tool.


Time to add the castor. If you bought one from Home Depot, then just attach it on the tapered end of the robot using screws. If you wish you may be creative like me, and build your own castor. I cut a piece of structural wire and threaded it through an RC AirCraft wheel. Then I just hot glued it to the chassis and placed a couple tabs of glue on the loop so that the wheel doesn't move too far off to either side.

Hot-Glueing the castor to the robot


Time to heat up that soldering iron again as we solder the leads of the motors to some wires that will serve as connectors or extensions to our receiver. Poke a wire through the loop on the motor lead and carefully twist the wire. Don't break the lead off (a mistake I made on BOTH my motors). Now solder it on. While you solder, it might be wise to remove the motor from the plastic gearbox in which it's contained. Just undo the strap holding downthe motor and gently pull it out. When you're done, slide it back in and replace the strap.

Once the Wire is soldered on, you can either crimp on another Molex connector, or just strip the tips of the wires and leave them as is.

Repeat for all the leads on both motors.


Now for the final step of the chassis.


Mark out the four holes you will be using to attach the motor brackets to the wooden portion of the chassis and drill them out using a small drill bit. Place the motors and attach the brackets to the chassis using the #2 sized screws and nuts.


Now for a finished view on the bottom of the robot.

Bottom of the robot Chassis. Similar to the CAD image, right?

You can really see the similarities between the CAD image and this final version.

If the brackets don't hold the motors well on their own, try inserting a #5 screw through the hole in the upper corner of the bracket, or use tape or velcro to create a stronger bond.


One last step. Take each wheel and insert the slotted side onto the motor shaft. Screw it in place with the screws included in the packaging.


Completed Chassis

There! The chassis is done!


Next we will Finish Up on Part 1 of the robot.


about the caster

Your caster wheels are kinda ghetto with all that hot glue =P

I recommend drilling a few holes and feed the wire through, and then bending it to hold it in place. Also, I think those wheels on the caster might be counterproductive. You might actually have less friction if you just used the wire alone, without the wheels.

Otherwise, you did a great job mounting on the side wheels, very solid! =)