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Trinket_Gemma_Servo_Control/README.md

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+# Trinket_Gemma_Servo_Control
+
+Code to accompany this Adafruit tutorial:
+https://learn.adafruit.com/trinket-gemma-servo-control

Trinket_Gemma_Servo_Control/Trinket_Gemma_Servo_Control.ino

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+/*******************************************************************
+  SoftServo sketch for Adafruit Trinket.  Turn the potentiometer knob
+  to set the corresponding position on the servo 
+  (0 = zero degrees, full = 180 degrees)
+ 
+  Required library is the Adafruit_SoftServo library
+  available at https://github.com/adafruit/Adafruit_SoftServo
+  The standard Arduino IDE servo library will not work with 8 bit
+  AVR microcontrollers like Trinket and Gemma due to differences
+  in available timer hardware and programming. We simply refresh
+  by piggy-backing on the timer0 millis() counter
+ 
+  Required hardware includes an Adafruit Trinket microcontroller
+  a servo motor, and a potentiometer (nominally 1Kohm to 100Kohm
+ 
+  As written, this is specifically for the Trinket although it should
+  be Gemma or other boards (Arduino Uno, etc.) with proper pin mappings
+ 
+  Trinket:        USB+   Gnd   Pin #0  Pin #2 A1
+  Connection:     Servo+  -    Servo1   Potentiometer wiper
+ 
+ *******************************************************************/
+
+#include <Adafruit_SoftServo.h>  // SoftwareServo (works on non PWM pins)
+
+#define SERVO1PIN 0   // Servo control line (orange) on Trinket Pin #0
+
+#define POTPIN   1   // Potentiometer sweep (center) on Trinket Pin #2 (Analog 1)
+
+Adafruit_SoftServo myServo1, myServo2;  //create TWO servo objects
+   
+void setup() {
+  // Set up the interrupt that will refresh the servo for us automagically
+  OCR0A = 0xAF;            // any number is OK
+  TIMSK |= _BV(OCIE0A);    // Turn on the compare interrupt (below!)
+  
+  myServo1.attach(SERVO1PIN);   // Attach the servo to pin 0 on Trinket
+  myServo1.write(90);           // Tell servo to go to position per quirk
+  delay(15);                    // Wait 15ms for the servo to reach the position
+}
+
+void loop()  {
+  int potValue;  // variable to read potentiometer
+  int servoPos;  // variable to convert voltage on pot to servo position
+  potValue=analogRead(POTPIN);                // Read voltage on potentiometer
+  servoPos = map(potValue, 0, 1023, 0, 179);  // scale it to use it with the servo (value between 0 and 180) 
+  myServo1.write(servoPos);                    // tell servo to go to position
+
+  delay(15);                              // waits 15ms for the servo to reach the position
+}
+
+// We'll take advantage of the built in millis() timer that goes off
+// to keep track of time, and refresh the servo every 20 milliseconds
+// The SIGNAL(TIMER0_COMPA_vect) function is the interrupt that will be
+// Called by the microcontroller every 2 milliseconds
+volatile uint8_t counter = 0;
+SIGNAL(TIMER0_COMPA_vect) {
+  // this gets called every 2 milliseconds
+  counter += 2;
+  // every 20 milliseconds, refresh the servos!
+  if (counter >= 20) {
+    counter = 0;
+    myServo1.refresh();
+  }
+}

Trinket_Gemma_Servo_Control/Trinket_Gemma_Servo_Control.py

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+import time
+import board
+from analogio import AnalogIn
+import simpleio
+
+# servo pin for the M0 boards:
+servo = simpleio.Servo(board.A2)
+angle = 0
+
+# potentiometer 
+trimpot = AnalogIn(board.A1)  # pot pin for servo control
+
+def remapRange(value, leftMin, leftMax, rightMin, rightMax):
+    # this remaps a value from original (left) range to new (right) range
+    # Figure out how 'wide' each range is
+    leftSpan = leftMax - leftMin
+    rightSpan = rightMax - rightMin
+
+    # Convert the left range into a 0-1 range (int)
+    valueScaled = int(value - leftMin) / int(leftSpan)
+
+    # Convert the 0-1 range into a value in the right range.
+    return int(rightMin + (valueScaled * rightSpan))
+
+while True:
+    angle = remapRange(trimpot.value, 0, 65535, 0, 180)
+    servo.angle = angle
+    #time.sleep(0.05)