mirror of
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245 lines
9.3 KiB
Markdown
245 lines
9.3 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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#### Initialisation options
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```python
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Button(pin=None, pull_up=True, bounce_time=None)
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```
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| Argument | Description | Values | Default |
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| -------- | ----------- | ------ | ------- |
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| `pin` | The GPIO pin number the button is connected to. | Integer | *Required* |
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| `pull_up` | The pull state of the pin. `True` means pull up, `False` means pull down. | Boolean | `True` |
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| `bounce_time` | Specifies the length of time (in seconds) that the component will ignore changes in state after an initial change. | Integer or Float | `None` |
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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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| `value` | The current value of the button. 0 if off; 1 if on. | Float |
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| `values` | A generator continuously yielding the button's current value. | Generator |
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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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#### Initialisation options
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```python
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MotionSensor(pin=None, queue_len=1, sample_rate=10, threshold=0.5, partial=False)
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```
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| Argument | Description | Values | Default |
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| -------- | ----------- | ------ | ------- |
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| `pin` | The GPIO pin number the sensor is connected to. | Integer | *Required* |
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| `queue_len` | ??? | Integer | `1` |
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| `sample_rate` | ??? | Integer | `10` |
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| `threshold` | Proportion of sensor values required to determine motion state. | Float: `0` to `1` | `0.5` |
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| `partial` | ??? | Boolean | `False` |
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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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| `value` | The current value of the sensor. 0 if still; 1 if motion. | Float |
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| `values` | A generator continuously yielding the sensor's current value. | Generator |
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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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#### Initialisation options
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```python
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LightSensor(pin=None, queue_len=5, charge_time_limit=10,
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threshold=0.1, partial=False)
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```
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| Argument | Description | Values | Default |
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| -------- | ----------- | ------ | ------- |
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| `pin` | The GPIO pin number the sensor is connected to. | Integer | *Required* |
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| `queue_len` | ??? | Integer | `5` |
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| `charge_time_limit` | Maximum amount of time allowed to determine darkness. | Integer | `10` |
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| `threshold` | Proportion of sensor values required to determine light level. | Float: `0` to `1` | `0.1` |
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| `partial` | ??? | Boolean | `False` |
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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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| `value` | The current value of the sensor. 0 if dark; 1 if light. | Float |
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| `values` | A generator continuously yielding the sensor's current value. | Generator |
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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 reads 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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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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# do something with pot
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```
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#### Initialisation options
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```python
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MCP3008(channel=0, device=0)
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```
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| Argument | Description | Values | Default |
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| -------- | ----------- | ------ | ------- |
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| `channel` | Which of the 8 ADC channels to access. | Integer: `0` to `7` | `0` |
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| `device` | Which of the two Chip Select SPI pins to access. | Integer: `0` or `1` | `0` |
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#### Properties
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| Property | Description | Type |
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| -------- | ----------- | ---- |
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| `channel` | The ADC channel the device is connected to. | Integer |
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| `device` | The chip select pin the device is connected to. | Integer |
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| `value` | The current value of the device. | Float |
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| `values` | A generator continuously yielding the device's current value. | Generator |
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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 reads their values in digital form.
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The interface is identical to `MCP3008`, except that only channels `0` to `3`
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are accessible.
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