Resistors are essential electronic components that limit the flow of electric current in a circuit. Because they’re so small, their resistance value (measured in ohms, Ω) is usually marked with colored bands instead of numbers. Here's how to read them:
What is a Capacitor?
A capacitor is an electronic component that stores electrical energy in an electric field. You can think of it like a tiny rechargeable battery, but it charges and discharges much faster and can’t hold energy for very long.
You’ve probably seen a spinning fan or display with LED lights that forms text or images in mid-air — it looks like magic! But what’s really happening?
This amazing effect is based on a concept called Persistence of Vision (POV). When an LED strip spins fast enough and its lights turn on and off at just the right times, your brain blends those quick flashes together. The result? You see a complete image - even though it’s really just a single line of lights moving in circles!
If you don’t rotate an object around its center of mass, it becomes unstable - causing vibrations, extra stress, and sometimes complete system failure.
What Is a Hall Effect Sensor?
A Hall Effect Sensor is a small electronic component that detects magnets. When a magnet comes close, it sends a signal to other devices, like an Arduino or an LED light. Think of it as a tiny switch that turns on whenever a magnet is nearby.
This is a program we created for the LED strip display course.
#include <Adafruit_NeoPixel.h> #define LED_COUNT 20 #define StripPin A2 #define HallEffectSensorPin 6 #define HallEffectGNDPin 5 #define HallEffectVCCPin 4 int startSeconds = 20; int startMinutes = 10; int startHours = 1; int secondsArrow; int minutesArrow; int hoursArrow; int arrowPosition; int hallSensorPastState = LOW; int hallSensorRead; int timeForOneRotation = 1; unsigned long RPMTimer = millis(); Adafruit_NeoPixel leds = Adafruit_NeoPixel(LED_COUNT, StripPin, NEO_GRB + NEO_KHZ800); int color[3] = {255, 100, 150}; int secondsColor[3] = {255, 0, 0}; int minutesColor[3] = {0, 255, 0}; int hoursColor[3] = {0, 0, 255}; void setup(){ pinMode(HallEffectSensorPin, INPUT); pinMode(HallEffectGNDPin, OUTPUT); pinMode(HallEffectVCCPin, OUTPUT); digitalWrite(5, LOW); digitalWrite(HallEffectVCCPin, HIGH); leds.begin(); leds.setPixelColor(19, color[0], Color[1], color[2]); } void loop(){ RPMUpdate(); ClearLedsWithoutTheLastOne(); arrowPosition = StateFrom60(); secondsArrow = ((int) floor(( millis() / 1000) + startSeconds) % 60); minutesArrow = ((int) floor(( millis() / 60000) + startMinutes) % 60); hoursArrow = ((int) floor(( millis() / 3600000) + startHours) % 12) * 5; if (arrowPosition == secondsArrow){ for (int i = 0; i < LED_COUNT - 3; i ++){ leds.setPixelColor(i, secondsColor[0], secondsColor[1], secondsColor[2]); } } if (arrowPosition == minutesArrow){ for (int i = 0; i < LED_COUNT - 6; i ++){ leds.setPixelColor(i, minutesColor[0], minutesColor[1], minutesColor[2]); } } if (arrowPosition == hoursArrow){ for (int i = 0; i < LED_COUNT - 10; i ++){ leds.setPixelColor(i, hoursColor[0], hoursColor[1], hoursColor[2]); } } if (arrowPosition % 5 == 0){ leds.setPixelColor(18, color[0], color[1], color[2]); leds.setPixelColor(17, color[0], color[1], color[2]); } leds.show(); } void RPMUpdate(){ hallSensorRead = digitalRead(HallEffectSensorPin); if(hallSensorRead != hallSensorPastState){ if(hallSensorRead == HIGH){ timeForOneRotation = millis() - RPMTimer; RPMTimer = millis(); hallSensorPastState = HIGH; } else{ hallSensorPastState = LOW; } } } void ClearLedsWithoutTheLastOne(){ for(int i = 0; i < LED_COUNT - 1; i ++){leds.setPixelColor(i, 0);} } int StateFrom60(){ return (int)floor(((millis() - RPMTimer) * 60) / timeForOneRotation) % 60; }
It doesn’t matter if you connect the wire to the positive (cathode) or the negative (anode) terminal of the battery.
Note that for power sources, the cathode and anode are marked opposite to that of diodes and other electronics. In them, the cathode is the positive terminal and the anode is the negative one.
Connecting the other side of the motor directly to the battery will turn it on, but we want a way to control when we turn it on without having to disconnect and reconnect cables constantly. For that reason, we added a switch between one of the connections from the motor to the battery. It may seem easier to use a larger switch, but the DIP switch is meant to be soldered to a PCB, and that is what we'll do in the end.
