Turn Table for photography

Hi folks,

i have been working on my little project to create a 360 degree photography turntable. In short, it has an arduino board, switch, IR diode and a modified digital servo to turn 360 degree. The servo basicaly turns a white wood board with a product for about 6°and uses the IR diode to send data to my DSLR to take automatically a photo. Everything is fine but the servo is acting unpredictable. Sometimes it turns 6°sometimes 10°and sometimes it randomly goes backward for about 20°. Dont know how to fix it and i tryed everything. Please help

In my code i use this to control the servo:

myservo.write(93.5);      // stop position of servo    
    (take photo with code)
    delay(6500);                  //wait to take photo
    myservo.write(92);     // move slow
    delay(400);

..how do you power the servo?

i power it with the same USB cable like my Arduino. Do u think this is the problem ?

Yes.. A servo can draw 800-1000mA when acting, based on the mechanical load, etc. You need a separate power supply 1A capable.

Ok thanks, i will try to use a power suply and let u know if it helped, thx :)

myservo.write(93.5);The standard Servo library write method takes only integer parameters.

Ok so i tryed some USB power adapters from ipad and iphone and the servo went crazy :) Curently i am powering it from USB in my macbook, but it seems to work like before. Any other suggestions ? The number 93,5 is working, but i tryed only 93 with no affect.

michalch: Any other suggestions ?

Give your servo a dedicated power supply providing a regulated output with the correct voltage for your servo, and at least 1A capacity (more if your servo has a higher current rating). Remember to connect the grounds. Depending how long you need it to run for, a rechargeable battery pack could be a convenient solution.

Interesting topic. Will help to work with photos. And to process too.

I'd recommend going with a stepper motor for more predictable turning and full range.