Electronics

In a circuit, ground is the common reference point for voltage and the return path for electric current. After electricity flows through components, it needs a clear way to get back to the power source. All ground connections are tied together, so every part of the circuit shares the same reference point, and the current can flow in a complete loop. This helps signals stay consistent, and components work correctly. If the grounds were not connected, parts of the circuit could act unpredictably or not work at all. In simple terms, connecting all grounds keeps current flowing properly and the circuit working reliably.

If everything is connected correctly, the Arduino microcontroller will light up, powered with 5V from the 9V battery!

A capacitor acts like a small energy buffer. It stores a little electricity and releases it when needed. When the controller or LED strip suddenly turns on or changes brightness, it can briefly pull a lot of current. The capacitor helps by smoothing out these quick changes, keeping the voltage steady. This protects the controller and LEDs from sudden voltage drops or spikes and helps everything run more reliably. In simple terms, the capacitor helps keep the power smooth and protects the electronics.

You’ll attach the lights to this stick, so choose its position carefully. Once the lights are attached, you can check where the center of weight is - that’s where you’ll mount the motor.

On our LED strip, there are two extra wires for power and ground. We don't need them, so we cut them off. There is also an extra connector on the remaining cables. As we will be soldering them to the board, we don't really need this connector, so we remove it as well.

While we can pass the cables around the PCB, we decided that it would look more appealing if they were to pass from underneath the PCB. While this is an easy way to do so, those more tech-savvy can solder 3 terminal blocks to the PCB, as a way to bypass the drilling task and create an easy way to replace the LED strip in the future.

Some LED strips have a sticky backing covered by a thin plastic layer. You can peel it off and stick the strip directly. If your strip is different from the one we suggested in the shopping section, you might need to get a little creative.

A Hall effect sensor is basically a tiny magnet detector. When a magnet comes near it, the sensor can “feel” the magnetic field and tell the circuit, usually by turning its output on or off. We can use it to detect things moving, like wheels spinning or doors opening.

Some microcontroller pins can act like tiny batteries (power) or tiny paths to ground. By setting a pin HIGH, it gives a little voltage to power something. By setting it LOW, it acts like ground, letting current flow back. This is useful for testing or powering small sensors,

In short: Hall sensors feel magnets, and digital pins can sometimes act like tiny power sources or grounds to help run them.

A pull-down resistor keeps the Hall sensor’s signal at zero when no magnet is near. Without it, the sensor could get confused and give random on/off signals. It makes sure the circuit can clearly tell when a magnet is present or not.