Reading the home position of a slotted wheel

I have a reel mechanism that uses a slotted optical encoder and a slotted wheel. The wheel has an absolute 'home'. The home position has 4 teeth, while the rest of the wheel has evenly spaced 2-tooth increments. I am having trouble figuring out the logic on how to 'home' the stepper motor at initialization. Would this be based on the amount of highs within a certain time? Any help or pointers would be appreciated!!!

Can you explain that in more detail, with a diagram or picture?

Hello
Post a picture of the hardware.

How wide are the 4 teeth together?
Paul


I am using a redboard and a easy driver for the stepper driver control.

That's possible but requires constant speed or some movement for the time determination.

Instead I'd suggest 2 sensors which can not normally both see a slot.

@DrDiettrich I see what you are saying with the two sensors, though I have to write this code for existing hardware only, as it will be implemented on dozens of repurposed gaming cabinets.

What's the cost of a possibly missed index position?

The reels are used for gaming cabinets. If the reel is not homed in the event of a power outage, and then restored, the player would be seeing symbols of a loss-while it may be a win, and vice-versa.

How many slot sensor (LED/hall) are there….
What’s their phase relationship to the wheel ?

@lastchancename There can only be one sensor per reel on these. Not sure of what you mean by phase relation ship, but I am seeing 22 highs per revolution. I use accelStepper for the motor and have 800 positions per full rotation.

@lastchancename is probably referring to a drawing like this - which involves two sensors to detect direction of rotation.

There may likely be a slight offset between the position indexer, and the home point index offset.
If that’s known, it might be possible to detect the home point while counting…

Better photos or a data sheet would be helpful.