Safe Dialer Stepper vs Servo

Projects General Guidance
1

I'm playing with a stepper motor but starting to think a servo may be the way to go.
So looking for some advice.

I need to rotate a safe dial 4 time anti-clock to a specified number then 3 times clock to another number etc.

Now with the cheapo stepper motor i'm experimenting with after a few times I start to drift and its not very accurate. A safe lock has a theoretical 1,000,000 combinations (Although that can be cut down dramatically to about 400,000 when know how).

So what would be the better approach to a sustained dialling attack like this.

I need to be able to accurately divide 360 degrees into 100 increments 3.6 degress
It would also be nice to get feedback when the motor stalls or cant move.

Thanks Tony

2

Is this kosher or should we be calling the police?

A stepper motor will be much more precise than a hobby servo.

...R

3

Robin2:
Is this kosher or should we be calling the police?

A stepper motor will be much more precise than a hobby servo.

...R

I wondered who would ask this.
I'm actually a locksmith LOL or am I.....

Maybe I just need to get a better stepper motor then.

Still not sure and keen for more input.

4

If your stepping motor drifts you need to get a better driver and software not motor.

Their is a servo that lets you have three turns but most will not do 360 degrees. They are not so accurate as a stepping motor.

5

When the judge asked the Locksmith what he was doing when he was arrested he said "Making a bolt for the door"

One way a stepper motor can "drift" is if it misses steps because it is being driven too fast or if it does not have enough torque to move the load. And torque reduces with speed.

You need to post a link to the datasheet for the stepper motor and tell us what stepper motor driver and stepper power supply (volts and amps) you are using.

...R
Stepper Motor Basics
Simple Stepper Code

6

Maybe this could be interesting Combo Breaker - motorized combo lock cracking device.

7

Whandall:
Maybe this could be interesting Combo Breaker - motorized combo lock cracking device.

Very interesting thank you!