Handle encoders with a state machine

[sconklin]

Differences between the old and new encoder methods:

Old code used string compares, New code uses an arrary lookup

Old code:

1. Tracked each change in the encoder signals as a movement in a direction
2. Accepted two movements in the same direction as movement in that direction.
3. Divided the number of changes by four to get a position
4. Old encoder made changes according to this table, which treats "no change" conditions 00 and 11 as movement (_). //directionEncoders +=8segmentEncoder; // head direction // old new result old new // 00 00 +1 0 0 () // 00 10 +1 0 2 // 10 11 +1 2 3 // 11 01 +1 3 1 // 01 00 +1 1 0 // // 01 11 -1 1 3 // 11 11 -1 3 3 (*) // 11 10 -1 3 2 // 10 00 -1 2 0 // 00 01 -1 0 1

New Code:

1. Counts each cycle through all 4 encoder values as a movement in a direction
2. Is able to declare a direction after one cycle
3. Does not divide by four to get a position
4. No movement is counted if input signals do not change

General Changes:

Used unsigned char where possible to save memory

Signed-off-by: Steve Conklin steve@conklinhouse.com

[sconklin]

I hope this works, I inspected it pretty carefully but I have no way to test it. Let me know if you have any questions.

[mcanet]

Hi Steve.

this night I did merge to my code. I am not completely sure what code suppose to do better. First I fixed code to get compiled and then tested with machine. Start with numbers like 1000 and when I move head start to increase even when encoder didn't move. if you want we can keep as separated branch and try to test it until works. I zipped the code that compiled.

I will go back main branch to my code by now. Anyway thanks for help.

Mar

On Fri, Mar 29, 2013 at 10:22 PM, Steve Conklin notifications@github.com wrote:

Differences between the old and new encoder methods:

Old code used string compares, New code uses an arrary lookup

Old code:

Tracked each change in the encoder signals as a movement in a direction Accepted two movements in the same direction as movement in that direction.

Divided the number of changes by four to get a position

Old encoder made changes according to this table, which treats "no change" conditions 00 and 11 as movement (_). //directionEncoders +=8segmentEncoder; // head direction // old new result old new // 00 00 +1 0 0 () // 00 10 +1 0 2 // 10 11 +1 2 3 // 11 01 +1 3 1 // 01 00 +1 1 0 // // 01 11 -1 1 3 // 11 11 -1 3 3 (*) // 11 10 -1 3 2 // 10 00 -1 2 0 // 00 01 -1 0 1

New Code:

Counts each cycle through all 4 encoder values as a movement in a direction Is able to declare a direction after one cycle Does not divide by four to get a position No movement is counted if input signals do not change

General Changes:

Used unsigned char where possible to save memory

Signed-off-by: Steve Conklin steve@conklinhouse.com

---

You can merge this Pull Request by running

git pull https://github.com/sconklin/knitic for-upstream

Or view, comment on, or merge it at:

https://github.com/mcanet/knitic/pull/22

Commit Summary

Handle encoders with a state machine

File Changes

M arduino_code/openKnitting_handMadepcb_v0_1/openKnitting_handMadepcb_v0_1.ino (201)

Patch Links:

https://github.com/mcanet/knitic/pull/22.patch https://github.com/mcanet/knitic/pull/22.diff