Robot ARm
Design & Build- BAse + ARm
I began by designing the base and arms of the robotic arm, keeping simplicity and function in mind. I sketched out a basic 4-DOF layout, then moved into Fusion 360 to create the CAD model. The challenge was balancing stability with range of motion — the base had to be solid enough to hold the weight of all the joints without wobbling, but compact enough to rotate smoothly with a standard servo. I opted for PLA as the print material since it’s easy to work with and stiff enough for a lightweight setup. For the arms, I designed modular segments that could house MG996R servos at the joints. Each arm segment had built-in slots for wiring and servo mounting, which helped keep the build clean and minimized external clutter. I’ve attached the STL files for the arm segments and base in case anyone wants to try building or modifying their own version.
Performance & Testing
Seeing each joint respond to the Arduino code felt super rewarding. I started with simple motion tests: rotating each servo one at a time to check for range, stability, and unexpected jittering. Once I confirmed the basic movements worked, I wrote a few test scripts to coordinate multiple servos at once, like simulating a basic pick-and-place motion.
I quickly realized precise movement required careful tuning. Some servos moved faster than others, and small differences in angle added up by the time I got to the end effector. I had to tweak delays and positions in the code to get smoother motion and avoid mechanical stress on the joints.
To push the limits, I gave it a small load—just a few grams—to see how well it held up. The base stayed stable, but the arm began to sag slightly when fully extended. That gave me ideas for future upgrades like adding structural reinforcements or switching to higher-torque servos. Overall, it was super satisfying to watch the arm come to life and respond exactly the way I programmed it.
Assembly & Electronics
This part definitely gave me the most trouble. Assembling the robot arm itself was easy enough—the servo brackets slotted nicely into the 3D-printed arms, and everything fit together as planned. But once I started wiring up the electronics, things got frustrating fast. It was my first time using an Arduino with multiple servos, and I underestimated how messy things could get with all the jumper wires, power lines, and signal connections.
The real headache was powering the servos. I quickly learned that drawing too much current through the Arduino’s 5V pin causes it to reset or even shut down. After some research (and a few failed attempts), I added an external power supply and used a common ground setup to avoid brownouts. Even then, connecting everything cleanly on a breadboard without things popping loose took a lot of trial and error.
The servo movements were jittery at first—mostly due to bad signal connections and noisy power. I spent so long tweaking wire placement and pin assignments before finally getting smooth, coordinated motion. Looking back, this part taught me a lot about power management and circuit layout under real-world conditions. Read more about it here.