Hello, im a begginer in arduino and this is the first time i post a question here, im doing and hexapod with 12 microservos using a servoshield like this one: Adafruit 16-Channel 12-bit PWM/Servo Shield - I2C interface : ID 1411 : $17.50 : Adafruit Industries, Unique & fun DIY electronics and kits and its respective library, problem is i cant find how much current i need to run all the servos at once, im using 4 NiMH AA 3000mAh 1.2v rechargeable batteries (giving a total of 4.8v at 3000mah) and , my microservos are TowerPro Sg90, in the specifications they say they run at min 4.8v so i should be fine, but i cant run more than 6 at the same time, sometimes even less.
I dont know if batteries are draining too fast or the 3000mA they provide are not enough. I saw a vid of someone runing 16 servos at once with the same servodhield also using 4AA batteries so i dont know what the problem is, and i want to make sure its not the current because if i needed more batteries i would need to do a weird setup in my hexapod.
Im trying to test it with the example code that the servoshield provides:
/***************************************************
This is an example for our Adafruit 16-channel PWM & Servo driver
Servo test - this will drive 16 servos, one after the other
Pick one up today in the adafruit shop!
------> Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface [PCA9685] : ID 815 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits
These displays use I2C to communicate, 2 pins are required to
interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>
// called this way, it uses the default address 0x40
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
// you can also call it with a different address you want
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);
// Depending on your servo make, the pulse width min and max may vary, you
// want these to be as small/large as possible without hitting the hard stop
// for max range. You'll have to tweak them as necessary to match the servos you
// have!
#define SERVOMIN 150 // this is the 'minimum' pulse length count (out of 4096)
#define SERVOMAX 600 // this is the 'maximum' pulse length count (out of 4096)
// our servo # counter
uint8_t servonum = 0;
void setup() {
Serial.begin(9600);
Serial.println("16 channel Servo test!");
pwm.begin();
pwm.setPWMFreq(60); // Analog servos run at ~60 Hz updates
yield();
}
// you can use this function if you'd like to set the pulse length in seconds
// e.g. setServoPulse(0, 0.001) is a ~1 millisecond pulse width. its not precise!
void setServoPulse(uint8_t n, double pulse) {
double pulselength;
pulselength = 1000000; // 1,000,000 us per second
pulselength /= 60; // 60 Hz
Serial.print(pulselength); Serial.println(" us per period");
pulselength /= 4096; // 12 bits of resolution
Serial.print(pulselength); Serial.println(" us per bit");
pulse *= 1000;
pulse /= pulselength;
Serial.println(pulse);
pwm.setPWM(n, 0, pulse);
}
void loop() {
// Drive each servo one at a time
Serial.println(servonum);
for (uint16_t pulselen = SERVOMIN; pulselen < SERVOMAX; pulselen++) {
pwm.setPWM(servonum, 0, pulselen);
}
delay(500);
for (uint16_t pulselen = SERVOMAX; pulselen > SERVOMIN; pulselen--) {
pwm.setPWM(servonum, 0, pulselen);
}
delay(500);
servonum ++;
if (servonum > 7) servonum = 0;
}