A simple MicroPython module for controling the MeArm
http://learn.mearm.com/
The example below uses a Raspberry Pi PICO-W but any Micro Controller with PWM GPIO pins should work.
For the MeArm class in mearm.py, you need to set the pins for each servo
self.height = Servo({'servo': 'height', 'pin': 0, 'min': 2500, 'max': 6000})
self.reach = Servo({'servo': 'reach', 'pin': 1, 'min': 5200, 'max': 6700})
self.grip = Servo({'servo': 'grip', 'pin': 2, 'min': 4300, 'max': 7600})
self.base = Servo({'servo': 'base', 'pin': 3, 'min': 2600, 'max': 7000})The MeArm controller board includes a 6 pin ribbon connector. 4 pins for the servos and 5v PWR and GND
The following table shows the PICO-W pins to MeArm board
| PICO | MrArm Board |
|---|---|
| 5V (Pin 40) | +5-9V |
| GND (Pin 39) | GND |
| GP0 (Pin 1) | LEFT |
| GP1 (Pin 2) | RIGHT |
| GP2 (Pin 4) | CLAW |
| GP3 (Pin 5) | BASE |
For setting the arms (horns) on your servos, follow the guide for your MeArm model in http://learn.mearm.com/
In the calibrate.py module there is a method for setting your servo to the mid-point. To do this use the set_to_center() method, setting your GPIO pin to the correct servo.
NOTE: Do not have the servo's connected to the MeArm while calibrating 😬
servo = Servo({'servo': 'height', 'pin': 0, 'min': 1200, 'max': 8200, 'mid': 4800})
servo.set_to_center()To control your MeArm, import the MeArm class from the mearm module. All servo controls are set by the percentage of position.
from mearm import MeArm
me_arm = MeArm()
me_arm.set_center()
me_arm.set_height(100)
me_arm.set_reach(60)
me_arm.set_grip(0)
me_arm.set_base(70)The following table provides the percentage to position
| Command | Position |
|---|---|
| height (100) | Raise arm to top position |
| reach (100) | Arm full forward reach |
| grip (100) | Close claw |
| base (100) | Rotate arm fully to the right |