RC Tank

Rc tank Demo-night

Second Modification: Projectile Launcher

For my second modification, I made a projectile launcher that uses a DC Motor, to launch the ammo, and screw nuts, which are the ammunition. I attached a wooden block to the shaft, so the wooden block rotates at a high speed like a fan blade. While the block is spinning, screw nuts will fall into the launcher. The rotating block would collide with the screw nuts and the nuts would be forced out of the launcher. To reduce the randomness of the direction the nuts would fly out, I encased the launcher on all sides but the front side. There is also enough space for the wooden block to spin in the encased launcher. Originally for this modification, I planned on using a small nerf gun. Failing to buy one, or anything similar, I came to the conclusion that it would be much more efficient for me to build it. I started experimenting with wooden boards because I knew it is a good material – thin and sturdy. Because I couldn’t get good idea for my projectile launcher, I started with simply writing down random thoughts that appeared in my head. This was the beginning of prototype one: the spring launcher.

Prototype One: Spring Launcher

This prototype used a pen spring and a wooden block to push ammunition. First, I drew a design on paper where a wooden block, that is attached to a spring, will push the projectile. The mechanism for this launcher is simple; a wooden block that is attached to a spring retracts, then is released to hit/push back a projectile. This is similar to stretching a rubber band, except the spring is inclined to stretch out. I also drew a wooden structure that supports the launch mechanism. The structure has 3 walls and a bottom. There is also a iron rod in the middle of the structure so the spring and block can stay fixed but still retract and stretch. I planned on using a DC motor or a servo motor to retract the spring, however that failed because I lacked the precision and skills to finely cut the small pieces of wood that were necessary. Therefore, I knew prototype one had failed and was not time-efficient to work on it any further.

Prototype Two: Circular Motion into Linear Motion

I still had remaining parts from prototype one and I believed those parts still had their uses, so I wanted to implement them in my second prototype. I started a new design with a DC motor as the foundation of the launcher. Because the motor only produced a circular motion, I needed to come up with an idea to change that circular motion into linear motion. I first thought about gears and how I could use them to shift a wood block or iron rod. I came up with an idea to use multiple wood blocks to transform circular motion into linear motion. I would have a dc motor rotate one block. A second block is attached to the first with an axle. The third is attached to the second, the fourth to the third, and all with axles. The fourth block would restricted by a case, which is from the first prototype to limit the block’s movement (the block slides perfectly within the case). How the blocks work exactly is written/drawn on my design papers. While I didn’t have any problems making the parts, I faced a problem after assembling them together. The weight of prototype two was too heavy for the DC motor and the tank. The DC motor lacked the strength to rotate a gear and four wooden blocks; the tank’s movement were much slower when the launcher was mounted on the tank. Since the launcher didn’t work and because I believed that speed was important to a RC tank, I decided to discard/disassemble prototype two.

Prototype Three: Simple Rotating Launcher

I came back to my design papers. I realized my thought process may have been too complicated for myself to practice in reality. After placing simplicity as the core of my third prototype, I drew the design for the Simple Rotating Launcher. For easier comprehension, this launcher is much like an electrical fan. After realizing that the DC motor needs gears to rotate heavy objects, I attached only one block to the DC motor. After some experiments, I knew that the a single rotating wooden block could kick the projectiles. To improve the accuracy of the projectiles, I made a support for the motor using remaining parts from prototype one and two. I also enclosed the launcher with cardboard to restrict the randomness of the projectiles’ directions. Prototype three worked and I decided to use it for my launcher. Now I had to make a reloader to prevent the jamming of the launcher.

Reloader

Prototype three by itself worked, but was a manual weapon. To make it more automatic, I decided to make reloader that used a servo. The task of the reloader was simple: to load the launcher with ammo when the ‘shoot’ button on the controller is pressed (I’ve set my PSB_PAD_UP as the shoot button). To accomplish this task the reloader needed two components: an ammo magazine and a mechanism or device that loaded those ammunitions into the launcher. I used screw nuts for ammunition and made a magazine according to the nuts’ sizes. For the mechanism, I used a servo. Initially, I tried to use the servo to push the ammo in the launcher. I changed that thought and used the servo like a gate or door. The magazine would be attached to the launcher on a slant, making the nuts inclined to fall into the launcher. The servo would stop the nuts from falling but would release them when the button is pressed. The making of my reloader turned out to be much easier.

First Modification: Ultrasonic Sensor

Process

I started with testing the ultrasonic sensor on a breadboard. Initially I wasn’t able to comprehend on how the sensor worked or how to use the sensor for my tank. After studying (I searched on Google and on Youtube for help), I began planning on using the sensor as a way for the tank to avoid obstacles. My first step was to momentarily freeze the tank; the tank shouldn’t continue moving when there could be a obstacle obstructing its path. By using an ‘if’ statement inside the control codes, the controller buttons wouldn’t work until the if statement was satisfied. Then I set the ‘if’ statements to rotate both motors in reverse until the sensor detected a distance over 10cm. The code was simpler than I had thought of and managed to finish my first modification.

Final Milestone

Connecting the Remote Controller

Process

My Starter Project is the Big Time Watch, which is a digital watch that operates on an ATmega328 (a pre-programmed microchip), a 7-segment LED display, a coin cell battery, capacitors, resistors, a 32kHz crystal, and a button. All components of the watch are soldered on to a firmware-based chip; the chip is covered with acrylic covers, which become the watch’s case. The ATmega328 controls the LED display of the watch while the 32kHz crystal manages the timing of the watch. The crystal can release a mechanical resonance by vibrating continuously; the released resonance becomes a electrical signal that has a precise frequency. How fast or slow the watch counts down is dependent on this frequency.Electrical power is provided by the cell battery and the button switches on the LED display (the display turns off after a second button press or after a time of inactivity).