mirror of
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231 lines
6.3 KiB
Markdown
231 lines
6.3 KiB
Markdown
# Input Devices
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These input device component interfaces have been provided for simple use of
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everyday components.
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Components must be wired up correctly before used in code.
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*Note all GPIO pin numbers use BCM numbering. See the [notes](notes.md) page
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for more information.*
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## Button
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A physical push button or switch.
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### Wiring
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Connect one side of the button to a ground pin, and the other to any GPIO pin:
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*Alternatively, connect to 3V3 and to a GPIO, and set `pull_up` to `False` when
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you create your `Button` object.*
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### Code
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Ensure the `Button` class is imported at the top of the file:
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```python
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from gpiozero import Button
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```
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Create a `Button` object by passing in the pin number the button is connected
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to:
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```python
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button = Button(2)
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```
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The default behaviour is to set the *pull* state of the button to *up*. To
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change this behaviour, set the `pull_up` argument to `False` when creating your
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`Button` object.
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```python
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button = Button(pin=2, pull_up=False)
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```
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### Methods
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| Method | Description | Arguments |
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| ------ | ----------- | --------- |
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| `wait_for_press()` | Halt the program until the button is pressed. | `timeout` - The number of seconds to wait before proceeding if no event is detected. Default: `None` |
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| `wait_for_release()` | Halt the program until the button is released. | `timeout` - The number of seconds to wait before proceeding if no event is detected. Default: `None` |
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### Properties
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| Property | Description | Type |
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| -------- | ----------- | ---- |
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| `pin` | The GPIO pin number the button is connected to. | Integer |
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| `is_pressed` | The current state of the pin (`True` if pressed; otherwise `False`). | Boolean |
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| `pull_up` | The pull state of the pin (`True` if pulled up; `False` if pulled down). | Boolean |
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| `when_pressed` | A reference to the function to be called when the button is pressed. | None or Function |
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| `when_released` | A reference to the function to be called when the button is released. | None or Function |
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## Motion Sensor
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A PIR (Passive Infra-Red) motion sensor.
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### Wiring
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Connect the pin labelled `VCC` to a 5V pin; connect the one labelled `GND` to
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a ground pin; and connect the one labelled `OUT` to any GPIO pin:
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### Code
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Ensure the `MotionSensor` class is imported at the top of the file:
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```python
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from gpiozero import MotionSensor
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```
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Create a `MotionSensor` object by passing in the pin number the sensor is
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connected to:
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```python
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pir = MotionSensor(4)
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```
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### Methods
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| Method | Description | Arguments |
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| ------ | ----------- | --------- |
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| `wait_for_motion()` | Halt the program until motion is detected. | `timeout` - The number of seconds to wait before proceeding if no motion is detected. Default: `None` |
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| `wait_for_no_motion()` | Halt the program until no motion is detected. | `timeout` - The number of seconds to wait before proceeding if motion is still detected. Default: `None` |
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### Properties
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| Property | Description | Type |
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| -------- | ----------- | ---- |
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| `pin` | The GPIO pin number the sensor is connected to. | Integer |
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| `motion_detected` | The current state of the sensor (`True` if motion is detected; otherwise `False`). | Boolean |
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| `when_motion` | A reference to the function to be called when motion is detected. | None or Function |
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| `when_no_motion` | A reference to the function to be called when no motion is detected. | None or Function |
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## Light Sensor
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An LDR (Light Dependent Resistor) Light Sensor.
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### Wiring
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...
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### Code
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Ensure the `LightSensor` class is imported at the top of the file:
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```python
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from gpiozero import LightSensor
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```
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Create a `LightSensor` object by passing in the pin number the sensor is
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connected to:
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```python
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light = LightSensor(4)
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```
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### Methods
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| Method | Description | Arguments |
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| ------ | ----------- | --------- |
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| `wait_for_light()` | Halt the program until light is detected. | `timeout` - The number of seconds to wait before proceeding if light is not detected. Default: `None` |
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| `wait_for_dark()` | Halt the program until darkness is detected. | `timeout` - The number of seconds to wait before proceeding if darkness is not detected. Default: `None` |
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### Properties
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| Property | Description | Type |
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| -------- | ----------- | ---- |
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| `pin` | The GPIO pin number the sensor is connected to. | Integer |
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| `light_detected` | The current state of the sensor (`True` if light; otherwise `False`). | Boolean |
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| `when_light` | A reference to the function to be called when light is detected. | None or Function |
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| `when_dark` | A reference to the function to be called when darkness is detected. | None or Function |
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## Temperature Sensor
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One-wire Digital Temperature Sensor.
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### Wiring
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...
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### Code
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Ensure the `TemperatureSensor` class is imported at the top of the file:
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```python
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from gpiozero import TemperatureSensor
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```
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Create a `TemperatureSensor` object:
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```python
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temp = TemperatureSensor()
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```
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### Methods
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...
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### Properties
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| Property | Description | Type |
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| -------- | ----------- | ---- |
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| `value` | The current temperature reading in degrees Celsius. | Float |
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## MCP3008 Analogue-to-Digital Converter
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MCP3008 ADC (Analogue-to-Digital converter).
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The MCP3008 chip provides access to up to 8 analogue inputs, such as
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potentiometers, and read their values in digital form.
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### Wiring
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...
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### Code
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Ensure the `MCP3008` class is imported at the top of the file:
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```python
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from gpiozero import MCP3008
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```
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Create an `MCP3008` object:
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```python
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pot = MCP3008()
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```
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Read the value of the device:
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```python
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print(pot.value)
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```
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Alternatively, access an input value with the `MCP3008`'s context manager:
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```python
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with MCP3008() as pot:
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print(pot.value)
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```
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It is possible to specify the `device` and the `channel` you wish to access.
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The previous example used the default value of `0` for each of these. To
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specify them, pass them in as arguments:
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```python
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pot = MCP3008(device=1, channel=7)
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```
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## MCP3004 Analogue-to-Digital Converter
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MCP3004 ADC (Analogue-to-Digital converter).
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The MCP3004 chip provides access to up to 4 analogue inputs, such as
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potentiometers, and read their values in digital form.
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The interface is identical to `MCP3008`.
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