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The Lynxmotion Smart Servos (LSS) are compact, modular and configurable actuators designed to be an evolution of the standard RC servo for use in multi-degree-of-freedom roboticsthat provide greater control than standard PWM servos. The servo lineup currently includes three “smart servos” which appear physically the same, sharing the same dimensions , and mounting points and output spline, but differing in maximum torque and speed.
Power: The servos need 6-12V, and 12v for maximum speed and torque.
Getting Started:
Action Action Commands:
The lynx motion has a simple serial protocol for controlling the motor, that is human-readable:
Number sign #
Servo ID number as an integer
Action command (two to three letters, no spaces, capital or lower case)
Configuration value in the correct units with no decimal
End with a control / carriage return '<cr>'
Ex: #5PD1443<cr>
Additional Parts:
Hookup with Power-hub
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Example Code for Arduino
While the Arduino library is not necessarily needed to control the smart servos, some of these examples make use of it.
This example cycles through the LED colours of the smart servos.
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#include <LSS.h>
#include <SoftwareSerial.h>
SoftwareSerial servoSerial(8, 9);
// give the id matching your device
#define LSS_ID (254) // ID 254 to broadcast to every motor on bus
// Create one LSS object
LSS myLSS = LSS(LSS_ID);
void setup()
{
servoSerial.begin(LSS_DefaultBaud);
LSS::initBus(servoSerial, LSS_DefaultBaud);
}
void loop()
{
// Loop through each of the 8 LED color (black = 0, red = 1, ..., white = 7)
for (uint8_t i = LSS_LED_Black; i <= LSS_LED_White; i++){
// Set the color (session only) of the LSS
//> https://www.robotshop.com/info/wiki/lynxmotion/view/lynxmotion-smart-servo/lss-communication-protocol/#H14.LEDColor28LED29
// Options are:
// LSS_LED_Black = 0
// LSS_LED_Red = 1
// LSS_LED_Green = 2
// LSS_LED_Blue = 3
// LSS_LED_Yellow = 4
// LSS_LED_Cyan = 5
// LSS_LED_Magenta = 6
// LSS_LED_White = 7
myLSS.setColorLED((LSS_LED_Color) i);
delay(1000);
}
} |
This example goes through the basic setup and movement
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| language | cpp |
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The power hub is the most universal way of connecting to the motors. You will need an external power source with a 5mm jack for 12v. Care should be taken when connecting the VIN pin, as this will be 12 volts!
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Example Code for Arduino
Ther is a custom LSS library for Arduino, but it's not necessarily needed to control the smart servos, and it is not compatible with the IAD shields for both MKR and Arduino Uno.
This example cycles through the LED colours of the smart servos.
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#include <SoftwareSerial.h>
#define rxPin 8
#define txPin 9
SoftwareSerial mySerial(rxPin, txPin); // Create the new software serial instance
#define LSS_ID 254 // ID 254 to broadcast to every motor on bus
void setup()
{
mySerial.begin(115200); // Important! this is the standard speed for talking to LSS
mySerial.print("#0D1500\r"); // this is used to clear the serial buffer
}
void loop()
{
// Loop through each of the 8 LED color (black = 0, red = 1, ..., white = 7)
for (uint8_t LEDCode = 0; LEDCode <= 7; LEDCode++){
// Set the color (session only) of the LSS
// Options are:
// LSS_LED_Black = 0
// LSS_LED_Red = 1
// LSS_LED_Green = 2
// LSS_LED_Blue = 3
// LSS_LED_Yellow = 4
// LSS_LED_Cyan = 5
// LSS_LED_Magenta = 6
// LSS_LED_White = 7
mySerial.print(String("#") + LSS_ID + String("LED") + LEDCode + "\r"); // set LED
delay(1000);
}
} |
This example goes through the basic setup and movement
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#include <SoftwareSerial.h> #define rxPin 8 #define txPin 9 SoftwareSerial mySerial(rxPin, txPin); // Create the new software serial instance #define LSS_ID 254 // ID 254 to broadcast to every motor on bus void setup() { mySerial.begin(115200); // Important! this is the standard speed for talking to LSS mySerial.print("#0D1500\r"); // this is used to clear the serial buffer } void loop() { // Move the LSS continuously in one direction mySerial.print(String("#") + LSS_ID + String("WR") + 10 + "\r"); // RPM move delay(5000); // Move the LSS continuously in the oposite direction mySerial.print(String("#") + LSS_ID + String("WR") + -10 + "\r"); // RPM move delay(5000); // faster! mySerial.print(String("#") + LSS_ID + String("WR") + -60 + "\r"); // RPM move delay(3000); // go Limp! mySerial.print(String("#") + LSS_ID + String("L") + "\r"); // Limp delay(5000); // move Moverelative thefrom LSScurrent continuouslyposition in the oposite direction myLSS.wheelRPM(-10); delay(5000); // faster! myLSS.wheelRPM(-60); delay(3000); // go Limp! myLSS.limp();1/10° (i.e 100 = 10 degrees) mySerial.print(String("#") + LSS_ID + String("D") + int(60*10) + "\r"); // move 100 degrees delay(5000); // moveMove relativeto from currentspecific position in 1/10° (i.e 100 = 10 degrees) myLSSmySerial.moveRelative(100); delay(5000); // Move to specific position in 1/10° (i.e 100 = 10 degrees) myLSS.move(400);print(String("#") + LSS_ID + String("D") + int(360*10) + "\r"); // move 360 degrees delay(7000); } |
Multiple Servos
For controlling multiple servos, you will first need to give each motor a unique ID. You will need to must attach each motor separately , and modify the code below to change it’s its ID to a value between 0 and 253. Afterwards, the servo will always remember it’s new ID.
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#include <LSS.h> #include <SoftwareSerial.h> SoftwareSerial servoSerialmySerial(8, 9); // ID set to default LSS ID = 0 #define LSS_ID_old (254)354 // ID 254 to broadcast to every motor on bus #define LSS_ID (0) // the new ID #define LSS_BAUD (LSS_DefaultBaud) // Create one LSS object LSS myLSS = LSS(LSS_ID); void setup() { mySerial.begin(115200); // Important! this setis the datastandard ratespeed for thetalking SoftwareSerialto portLSS servoSerialmySerial.begin(LSS_BAUDprint("#0D1500\r"); // this is used to clear the serial buffer servoSerial.print("#0D1500\r"); delay(1000); LSS::initBus(servoSerial, LSS_BAUD clear the serial buffer delay(1000); //change ID servoSerialmySerial.print(String("#") + LSS_ID_old + String("CID") + LSS_ID + "\r"); delay(2000); } void loop() { } |
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#include <LSS<SoftwareSerial.h> #include <SoftwareSerial.h> SoftwareSerial servoSerialmySerial(8, 9); #define LSS_ID1 (1) #define LSS_ID2 0 int direction = -1; void setup() { mySerial.begin(0115200); #define LSS_BAUD (LSS_DefaultBaud) // Create two LSS objects LSS myLSS1 = LSS(LSS_ID1); LSS myLSS2 = LSS(LSS_ID2); int direction = -1; void setup// Important! this is the standard speed for talking to LSS mySerial.print("#0D1500\r"); // this is used to clear the serial buffer } void loop() { servoSerial.begin(LSS_BAUD); // Initialize the LSS bus LSS::initBus(servoSerial, LSS_BAUD); Serial.begin(LSS_BAUD); } void loop() { // motor direction myLSS1.wheelRPM(-direction*60); myLSS2.wheelRPM(60*direction); delay(4000// motor direction mySerial.print(String("#") + LSS_ID + String("WR") +-direction*60) + "\r"); // RPM move mySerial.print(String("#") + LSS_ID + String("WR") + 60*direction + "\r"); // RPM move delay(5000); // reversreverse dierctiondirection direction = -direction; } |
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A reset may sometimes be needed
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#include <LSS.h> #include <SoftwareSerial.h> SoftwareSerial servoSerial(8, 9); // ID set to default LSS ID = 0 #define LSS_ID_old (254) // ID 254 to broadcast to every motor on bus #define LSS_BAUD (LSS_DefaultBaud)ID 254 // ID Create254 oneto LSSbroadcast objectto LSSevery myLSSmotor = LSS(LSS_ID);on bus void setup() { mySerial.begin(115200); // Important! //this setis the datastandard ratespeed for thetalking SoftwareSerialto portLSS servoSerialmySerial.begin(LSS_BAUDprint("#0D1500\r"); // this is used to clear the serial buffer servoSerial.print("#0D1500\r"); delay(1000); LSS::initBus(servoSerial, LSS_BAUD); // reset servoSerialmySerial.print(String("#") + LSS_ID_old + String("DEFAULT")+"\r"); delay(500); servoSerialmySerial.print(String("#") + LSS_ID_old + String("CONFIRM")+"\r"); delay(2000); } void loop() { } |
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TIP: Use the millis() function to find the elapsed time.
Possible Solution: This is one solution , but it could use some improvement: It needs a denounce and a pause without delay function to avoid blocking your code. This solution uses an older arduino library that might need to be updated.
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#include <LSS.h>
#include <SoftwareSerial.h>
SoftwareSerial servoSerial(8, 9);
// ID set to default LSS ID = 0
#define LSS_ID (0)
#define LSS_BAUD (LSS_DefaultBaud)
// Create one LSS object
LSS myLSS = LSS(LSS_ID);
int ServoPosition = 0;
bool counting = true;
int resetTime = 0;
int lastMovement;
void setup() {
servoSerial.begin(LSS_BAUD);
// Initialize the LSS bus
LSS::initBus(servoSerial, LSS_BAUD);
Serial.begin(LSS_BAUD);
myLSS.move(0);
// allow time to move to 0 position
delay(3000);
myLSS.setMaxSpeed(600, LSS_SetConfig);
//buttons
pinMode(11, INPUT);
pinMode(10, INPUT);
}
void loop() {
delay(1000);
if (counting) {
int seconds = (millis() - resetTime)/1000; // see below for an explanation of resetTime
ServoPosition = seconds * 60; // if we divide 360 by 60 we get 6.0 degrees
myLSS.move(ServoPosition); // move servo to position
Serial.println(seconds);
lastMovement = millis();
} else {
resetTime = millis() - lastMovement; // this helps us return to the last position of the clock movement
}
// buttons
if (digitalRead(10) == HIGH) {
// stop or start
counting = !counting;
Serial.println("Start/Stop");
// this could be improved on with a debounce!
}
if (digitalRead(11) == HIGH) {
// reset
Serial.println("reset");
myLSS.move(0);
delay(2000);
resetTime = millis(); // we use this to restart our counter from 0
}
} |
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