View source for Experiment 23: TTP223 Capacitive Touch Experiment

*[[Basic Experiment Kits For Arduino]]
*[[Basic Experiment Kits For Raspberry Pi]]
== Parameter Description ==
*Output mode can be selected via ports W1 and W2
**Pin W1 provides selection between direct mode and trigger mode
**Pin W2 provides selection between fast mode and low-power mode
***W1=0, W2=0: Output is in direct mode, high level active
***W1=0, W2=1: Output is in direct mode, low level active
***W1=1, W2=0: Output is in trigger mode, power-on state is 0
***W1=1, W2=1: Output is in trigger mode, power-on state is 1

== Arduino ==
=== Experimental Phenomenon ===
* When the button is pressed, the onboard LED lights up.
* When the button is released, the onboard LED turns off.

=== Circuit Connection ===
*[[File:实验二十三：TTP223电容触摸实验_接线.png|800px]]

=== Reference Program ===
<pre>
#define SEN 3
#define LED 13

int value = 0;

void setup()
{
  pinMode(LED,OUTPUT);
  pinMode(SEN,INPUT);
  Serial.begin(9600);       //Baud rate 9600
}

void loop()
{
  value = digitalRead(SEN); 
  if(value == HIGH)               //ADBuffer value is less than the set value, equivalent to temperature being greater than the set value 
  {
digitalWrite(LED,HIGH);  //Turn on LED 
    Serial.println("TTP223 has been pressed");
  }
  else
  {
   digitalWrite(LED,LOW);    //Turn off LED
  }
  delay(500);        //Delay 500ms
}
</pre>

== Raspberry Pi ==
=== Circuit Connection ===
*[[File:实验二十三：TTP223电容触摸实验_接线1.png|800px]]

=== Program Execution ===
==== Python ====
* Install the gpiozero library
**You can use the following command to install the library:
<pre>
sudo apt update
sudo apt install python3-gpiozero
</pre>
:*For other systems on the Raspberry Pi, you can use the following command to install the library:
<pre>
sudo pip3 install gpiozero
</pre>
:*Run the following command to view the GPIO pin definitions on the Raspberry Pi:
<pre>
pinout
</pre>
*Download the Raspberry Pi reference example, unzip the file, copy it to the user directory, and run it:
<pre>
cd raspberrypi/23/python_gpiozero
python sensor.py
</pre>
*At this point, you can see that the Raspberry Pi is running the program correctly. To exit, press ctrl+C.
*Command description: '''gpiozero.Button(pin, pull_up, active_state, bounce_time, hold_time, hold_repeat)'''
**Button inherits from DigitalInputDevice and represents a simple button or switch. One end of the button is connected to ground, and the other end is connected to any GPIO pin; or one end of the button is connected to the 3V3 pin, and the other end is connected to any GPIO pin, and then set pull_up to False in the Button's initialization constructor.
**Main parameters:
***pin: GPIO pin number;
***pull_up: Internal pull-up/pull-down resistor setting,
****When set to True (default), the GPIO pin is pulled high, and the other end of the button needs to be connected to ground.
****When set to False, the GPIO pin is pulled low, and the other end of the button needs to be connected to 3V3.
****When set to None, the GPIO pin is floating, and gpiozero cannot guess the active state, so active_state must be set.
***active_state:
****When set to True, the software pin state is also "high" when the hardware pin state is "high".
****When set to False, the input polarity is reversed, and when the hardware pin state is "high", the software pin state is "low".
****When pull_up is set to None, use this parameter to set the unknown pin active state.
****When pull_up is set to True or False, the pin's active state is automatically assigned.
***bounce_time: Software debounce time. Generally, the signal of a switch is unstable within about 20ms, known as "switch bounce".
****When set to None, software debounce compensation is not performed; otherwise, this parameter is the length of time (in seconds) that the component ignores after the initial change, with a default of 1s.
***hold_time: The time after pressing the button until when_held is triggered, in seconds.
***hold_repeat:
****If True, as long as the button remains pressed, when_held will continue to be triggered every hold_time interval.
****If False, when_held will only be triggered once.

*Command description: '''gpiozero.LED(pin, pwm, active_high, initial_value)'''
**Main parameters:
***pin: GPIO pin number,
***active_high:
****When set to True (default), connect the negative lead of the LED to GND and the other end to the GPIO pin.
****When set to False, connect the negative lead of the LED to the GPIO pin and the other end to the 3.3V pin.
***initial_value:
****If False (default), the LED initial state is off.
****If None, the LED pin is in an unstable state.
****If True, the LED initial state is on.
*For more commands, please refer to the [https://gpiozero.readthedocs.io/en/latest/installing.html gpiozero documentation]

== Example Download ==
* [[:File:Basic Experiment Kits For Arduino.zip|Arduino Example Programs]]
* [[:File:Basic Experiment Kits For Raspberry Pi.zip|Raspberry Pi 5 Example Programs in Python]]

== Related Examples ==
{{Arduino and Raspberry Pi Case}}