First, even without microcontroller electronics can make lot of fun stuff. For example, make a safe with servos & NE555 timers.
A servo motor is a rotary or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration. Servos are used extensively in robotics, computer numerical control (CNC) machinery, and other applications where precision control is required.
- Components: A typical servo consists of a motor, a sensor (usually a potentiometer) to detect the motor’s current position, and a control circuit.
The NE555 timer is an integrated circuit (IC) that’s been popular for decades due to its versatility, reliability, and simplicity. It can be used in various timer, delay, pulse generation, and oscillator applications.
- Modes of Operation:
- Monostable Mode (One-Shot): When triggered, the NE555 produces a single output pulse of a defined duration and then stops. This is often used for creating time delays.
- Astable Mode (Oscillator): The NE555 continuously oscillates, producing a square wave output. The frequency and duty cycle of this wave can be adjusted with external resistors and capacitors.
- Bistable Mode (Flip-Flop): The NE555 can be set up to toggle its output based on the state of two inputs, essentially acting as a simple memory element.
- Applications:
- Pulse Generation: Creating PWM signals, for example, for servo control.
- Time Delays: Introducing a delay in a circuit.
- Tone Generation: Making simple buzzers or musical tones.
- LED Flashers: Making LEDs blink at a set frequency.
- Oscillators: For tasks that require a regular pulse or oscillation.
Reference this for further understanding of NE555 timer.
The NE555 timer can function as an oscillator when configured in its astable mode. In this mode, the timer continuously alternates between its high and low states, producing a square wave output. This oscillation is based on the charging and discharging of an external capacitor through two external resistors.
Here’s how the NE555 functions as an oscillator in the astable mode:
1. Components and Connections:
- Connect pins 4 (RESET) and 8 (VCC) to the positive supply voltage to disable the reset functionality.
- Connect pin 1 (GND) to the ground.
- Connect an external capacitor, �C, between pin 2 (TRIGGER) and the ground.
- Connect an external resistor, �1R1, between pins 7 (DISCHARGE) and 8 (VCC).
- Connect another external resistor, �2R2, between pins 7 (DISCHARGE) and 2 (TRIGGER).
- Connect pins 2 (TRIGGER) and 6 (THRESHOLD) together.
2. Oscillation Mechanism:
- Initial State (Output High):
- At power-up, the capacitor �C is uncharged, so the voltage across it is 0V.
- This makes the voltage at the TRIGGER pin (pin 2) less than ���33VCC.
- This causes the internal flip-flop to set the output (pin 3) to HIGH and the DISCHARGE pin (pin 7) to be open-circuited (high impedance state).
- The capacitor �C starts charging through resistors �1R1 and �2R2.
- Switching to Low State:
- As the capacitor charges, the voltage across it increases.
- Once the voltage across the capacitor reaches 2���332VCC, the THRESHOLD pin (pin 6) senses this.
- The internal flip-flop then resets, which makes the output (pin 3) go LOW and connects the DISCHARGE pin (pin 7) to the ground.
- The capacitor starts discharging through �2R2.
- Switching Back to High State:
- The capacitor discharges until its voltage drops below ���33VCC.
- This causes the TRIGGER pin (pin 2) to again set the internal flip-flop, making the output go HIGH and disconnecting the DISCHARGE pin from the ground.
- The cycle then repeats, and the capacitor starts charging again.
This continuous charging and discharging of the capacitor create a square wave oscillation at the OUTPUT pin (pin 3).
It can be used as a timer (monostable mode), and a flip flop (bistable mode) too.
PIC Microcontroller: PIC stands for “Peripheral Interface Controller.” These are a family of microcontrollers produced by Microchip Technology.
You can build a flashing LED or program an analog clock.
Naixian Zhang 