Merge pull request #923 from pimoroni/patch/inventor_encoders
Added example for reading speeds from Inventor 2040W's encoders
This commit is contained in:
commit
a87d5581aa
|
@ -4,6 +4,7 @@
|
||||||
- [Read ADCs](#read-adcs)
|
- [Read ADCs](#read-adcs)
|
||||||
- [Read GPIOs](#read-gpios)
|
- [Read GPIOs](#read-gpios)
|
||||||
- [Read Encoders](#read-encoders)
|
- [Read Encoders](#read-encoders)
|
||||||
|
- [Read Speeds](#read-speeds)
|
||||||
- [LED Rainbow](#led-rainbow)
|
- [LED Rainbow](#led-rainbow)
|
||||||
- [Reset Inventor](#reset-inventor)
|
- [Reset Inventor](#reset-inventor)
|
||||||
- [Motor Examples](#motor-examples)
|
- [Motor Examples](#motor-examples)
|
||||||
|
@ -22,13 +23,14 @@
|
||||||
- [Velocity Tuning](#velocity-tuning)
|
- [Velocity Tuning](#velocity-tuning)
|
||||||
- [Position on Velocity Tuning](#position-on-velocity-tuning)
|
- [Position on Velocity Tuning](#position-on-velocity-tuning)
|
||||||
- [Servo Examples](#servo-examples)
|
- [Servo Examples](#servo-examples)
|
||||||
- [Single Servos](#single-servo)
|
- [Single Servo](#single-servo)
|
||||||
- [Multiple Servos](#multiple-servos)
|
- [Multiple Servos](#multiple-servos)
|
||||||
- [Simple Easing](#simple-easing)
|
- [Simple Easing](#simple-easing)
|
||||||
- [Servo Wave](#servo-wave)
|
- [Servo Wave](#servo-wave)
|
||||||
- [Calibration](#calibration)
|
- [Calibration](#calibration)
|
||||||
- [Audio Examples](#audio-examples)
|
- [Audio Examples](#audio-examples)
|
||||||
- [Tone Song](#tone-song)
|
- [Tone Song](#tone-song)
|
||||||
|
- [Motor Song](#motor-song)
|
||||||
|
|
||||||
## Function Examples
|
## Function Examples
|
||||||
|
|
||||||
|
@ -50,6 +52,12 @@ Shows how to initialise and read the 6 GPIO headers of Inventor 2040 W.
|
||||||
Demonstrates how to read the angles of Inventor 2040 W's two encoders.
|
Demonstrates how to read the angles of Inventor 2040 W's two encoders.
|
||||||
|
|
||||||
|
|
||||||
|
### Read Speeds
|
||||||
|
[read_speeds.py](read_speeds.py)
|
||||||
|
|
||||||
|
Demonstrates how to read the speeds of Inventor 2040 W's two encoders.
|
||||||
|
|
||||||
|
|
||||||
### LED Rainbow
|
### LED Rainbow
|
||||||
[led_rainbow.py](led_rainbow.py)
|
[led_rainbow.py](led_rainbow.py)
|
||||||
|
|
||||||
|
|
|
@ -0,0 +1,46 @@
|
||||||
|
import time
|
||||||
|
from inventor import Inventor2040W, NUM_MOTORS # , MOTOR_A, MOTOR_B
|
||||||
|
# from pimoroni import REVERSED_DIR
|
||||||
|
|
||||||
|
"""
|
||||||
|
Demonstrates how to read the speeds of Inventor 2040 W's two encoders.
|
||||||
|
|
||||||
|
Press "User" to exit the program.
|
||||||
|
"""
|
||||||
|
|
||||||
|
# Wheel friendly names
|
||||||
|
NAMES = ["LEFT", "RIGHT"]
|
||||||
|
|
||||||
|
# Constants
|
||||||
|
GEAR_RATIO = 50 # The gear ratio of the motor
|
||||||
|
SPEED = 1.0 # The speed to drive the motors at
|
||||||
|
SLEEP = 0.1 # The time to sleep between each capture
|
||||||
|
|
||||||
|
# Create a new Inventor2040W
|
||||||
|
board = Inventor2040W(motor_gear_ratio=GEAR_RATIO)
|
||||||
|
|
||||||
|
# Uncomment the below lines (and the top imports) to
|
||||||
|
# reverse the counting direction of an encoder
|
||||||
|
# encoders[MOTOR_A].direction(REVERSED_DIR)
|
||||||
|
# encoders[MOTOR_B].direction(REVERSED_DIR)
|
||||||
|
|
||||||
|
# Set both motors driving
|
||||||
|
for motor in board.motors:
|
||||||
|
motor.speed(SPEED)
|
||||||
|
|
||||||
|
# Variables for storing encoder captures
|
||||||
|
captures = [None] * NUM_MOTORS
|
||||||
|
|
||||||
|
# Read the encoders until the user button is pressed
|
||||||
|
while not board.switch_pressed():
|
||||||
|
|
||||||
|
# Capture the state of all the encoders since the last capture, SLEEP seconds ago
|
||||||
|
for i in range(NUM_MOTORS):
|
||||||
|
captures[i] = board.encoders[i].capture()
|
||||||
|
|
||||||
|
# Print out the speeds from each encoder
|
||||||
|
for i in range(NUM_MOTORS):
|
||||||
|
print(NAMES[i], "=", captures[i].revolutions_per_second, end=", ")
|
||||||
|
print()
|
||||||
|
|
||||||
|
time.sleep(SLEEP)
|
|
@ -6,6 +6,7 @@ This library offers an `Encoder` class that uses Programmable IO (PIO) hardware
|
||||||
|
|
||||||
|
|
||||||
## Table of Content
|
## Table of Content
|
||||||
|
- [Table of Content](#table-of-content)
|
||||||
- [Encoder](#encoder)
|
- [Encoder](#encoder)
|
||||||
- [Getting Started](#getting-started)
|
- [Getting Started](#getting-started)
|
||||||
- [Count and Angle](#count-and-angle)
|
- [Count and Angle](#count-and-angle)
|
||||||
|
@ -102,7 +103,22 @@ degrees_per_second
|
||||||
radians_per_second
|
radians_per_second
|
||||||
```
|
```
|
||||||
|
|
||||||
Internally `.capture()` does the same up-front reading of values but does so more optimally within the underlying C++ driver. As an added bonus, it calculates encoder speeds too, by using the captured `delta` along with timing information returned by the PIO, more accurately than estimating a speed from the `delta` alone.
|
Internally `.capture()` does the same up-front reading of values but does so more optimally within the underlying C++ driver. It calculates encoder speeds too, by using the difference between the current `count` and the **last capture's** `count` (aka the `delta`), along with timing information returned by the PIO. This produces speed readings that are more accurate than estimating a speed from the `delta` alone.
|
||||||
|
|
||||||
|
:information_source: **It is recommended to perform captures frequently and at a consistent rate.** If this is not possible for your project, consider performing a dummy capture at the start of the time window you actually wish to measure the encoder's speed over.
|
||||||
|
|
||||||
|
```python
|
||||||
|
# Perform a dummy capture to clear the encoder
|
||||||
|
enc.capture()
|
||||||
|
|
||||||
|
# Wait for the capture time to pass
|
||||||
|
time.sleep(CAPTURE_TIME)
|
||||||
|
|
||||||
|
# Perform a capture and read the measured speed
|
||||||
|
capture = enc.capture()
|
||||||
|
|
||||||
|
print("Speed =", capture.revolutions_per_second)
|
||||||
|
```
|
||||||
|
|
||||||
|
|
||||||
### State
|
### State
|
||||||
|
|
Loading…
Reference in New Issue