Robot Tank Made From Scratch

Ladies & Gentlemen
Behold!
I present to you, my greatest creation (yet)

This (non lethal) robotic tank was created from SCRATCH. That's right, all by myself (a high school student), from scratch!
Such toy is driven with two windshield wiper motors powered by a 12v 5ah SLA battery ---- it is controlled via bluetooth and RC controller.

The features of my robot include:
Two windshield wiper motors (powered by a 12v 5ah SLA battery) driving two gears as a support bar causes the back gears to follow the rotation
a wireless spy camera in the front --- footage viewed on TV with its transmitter
a distance sensor in the front
a buzzer on the back (I don't know why?)
lights for cosmetics
Two servo switches (operating the motion of the motors) that are controlled with a futaba (6 channel) RC receiver.
The distance sensor and the buzzer are operated with a EZ-Robot Bluetooth controller --- I have often used this instead of the RC controller --- I can control more things and can use a PC gaming joystick (connected to my laptop) to operate it.
---->More fun facts follow in the remainder of the steps. (sorry that pictures with some features are missing but I will update the thread as soon as possible -- don't have the project on me right now)

The project was created for two reasons --- to share the designs and gain ideas for future upgrades
and to gain votes for the instructables challenge (please vote for all three of my threads in all the contests I have entered).

I am an engineer in the making and I love creating robots from scratch.  

p.s. this project is really awesome and i advice that you check out all the steps --- each one has a surprise and 3d files are at the end
p.p.s. the videos are worth watching 

Step 1: Preparations -- 3D Models

At first I used blender (an open source 3 modeling and animation program) to create 3d meshes that I rendered as 2d images for blueprints. I also created some animation of the 3d models to predict the ideal movements and to see how the final product would look like.

The links for the 3d files are on the last step

Step 2: Materials

If you are to recreate my project or follow my blueprints, you will require a LOT of (multi-type + multi-dimensional) wood.
1/2 PVC pipe
1/2 wooden dowel
2 wiper motors
2 hitec servos
2 dual pole switches
2 packs of screws and washers
4 speaker wires
1 12v 5ah SLA battery
1 Electric Drill
Wood shop machinery (band saw, coping saw, table saw, etc...)
2 servo extensions
2 metal flanges (1/2 in bore)
Any servo controller of your choice ( I used EZ-Robot Bluetooth controller and Futaba 6 channel RC controller for servo control)
Paint of your preference
Basic tools (screw driver, wrench, hammer, etc...)

The most expensive items were: SLA Battery and the Wiper Motors

Step 3: Chassis

Creating the frame was one of the easiest part of the project. It did not take a long time. 
At first, I planned to operate all four gears with metal sprockets and a bike chain driven from an indirect drive --- that is why I have two gaps on the bottom of the frame and extra holes on the sides. Unfortunately, the sprockets for the motors were stolen and so I had to use a direct drive.

I moved up the 3 holes for the motors (for direct drive) and installed the switches. Since the gaps on the bottom of the frame was cut on a table saw, I filled up the gaps with hot glue. I put in two giant bolts as handles on the back so I can lift the frame more comfortably. Soon, I tested the switches.

Step 4: Tracks

With the Gear Template Generator Program, I created a die for the gears and the links.

Soon I manually cut out and sanded each link, drilled through the connecting dowels, hammered in a pvc pipe (for smooth giveaway of the teeth) and screwed together the tracks. As for the gears, I cut out the four gears on a coping saw after tracing the pattern from the die on a block that I glued together. 

p.s. the metal sprockets you see below were originally for the indirect drive planned earlier.

Step 5: Problems & Solutions

One of the major problems I encountered was that the wooden flange that was attached to the gears and motors wasn't strong enough and so it broke.

Plan B was a success as I replaced the wooden flange with a metal flange. I drilled and tapped through a hole on the flat part of the metal flange so a screw will hit off on the flat spot (that I grinded on the motor) and move the gears when the motors spin.

Another major problem was that I need to create/use a spacer and a stopper for the following gears so they would stop wiggling so much.

Hence, I created a pvc spacer and used a pvc coupler as a stopper for the following gears:

Step 6: Programming & Cosmetics

Once I was finished, I screwed in everything together and attached the cosmetics

By cosmetics, I mean the Futaba 6 channel RC receiver + transmitter and a wireless spy cam (viewed via tv) .

Consecutively, I used EZ-Robot bluetooth controller (a wireless servo controller that can also be used to operate a distance sensor and a joystick)

I also took the liberty to wire in some 5amp LED lights on the gears. 

I also attached a ping radar sensor and "attempted" to attach a GPS sensor (but I don't know how to use it so I left it alone)

For the RC controller it wasn't much of a hassle as it easily controlled the servos but I often use the EZ-B for universal controlling as it can power and operate all cosmetics + switches.

As for the EZ-B, I connected the radar sensor and a buzzer (on the back -- for speaker tones) to it and it worked well. With a microphone, I gave it (basic) commands, and it worked.

Here is the joystick layout I used for the tracks

Step 7: The Triumph

To sum it all up, it was one of the most difficult project I have ever created. It took extensive time to create the parts and an even longer time to design it (the 3d models). If I had a laser printer, I would have been create my own parts (e.g. flanges).

This robot will be my toy for the foreseeable future; someday I'll probably say that I see your RC car and raise you my tank.

The crawlerbot 2000 was created for two purposes --- to share the designs + gain ideas for future upgrades
and to gain votes for the instructables contests (please vote for all three of my posts in all the contests I have entered :) ).

As some of you might know, I promised you in my very first instructable (Wall-E Made from Scratch) that I will one day create a tank, and so I have lived up to my word. Please, vote for me in the contest: If I am to win any of the prizes, the contributions and future usage of most of them (like the laser printer) will be by my school, for the future engineering students to utilize and progress. 

Here is the link to download all the 3d models

https://dl.dropboxusercontent.com/u/18723152/TANK%203D%20Models.rar

p.s. every vote counts, please help me get votes