Arduino project · Motors and movement · Medium
Two-Joint Robot Arm with Knobs
Two knobs move the two joints of a small robot arm: the base and the elbow.
What you will learn
- How an arm has joints
- How each knob sets one servo angle
- Why servos need a separate 5 V supply
How it works
Each Map step turns a knob (0 to 100 percent) into an angle (0 to 180 degrees) for one servo.
Try this next
- Add a gripper.
- Record and replay positions.
- Limit the angles to protect the arm.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
A robot arm with joints
Each servo is one joint of the arm. Move the knobs, keys or joystick and watch the real arm bend.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Servo 1, 2 and 3 = the arm joints from the base up