Anybody know the _real_ name of Binary Ring Sequences?
I've spent 4 days now trying to find the "real" name of what I remember Don Lancaster (from Popular Electronics magazine) writing about 35 years ago. I also remember starting a fairly lengthy thread in sci.electronics.desgin on Usenet if anybody knows an archive that goes back 15+ years. What I remember is "Binary Ring Codes" or "Binary Ring Sequences".
The idea is fairly simple. The sequence is simply a series of 1's and 0's of any specifed length. If I remember right there are only 2 for a given length and they are compilements (ie 1's and 0's are reversed). The whole point is that for each sequence it is possible to determine your position in the sequence from just a small "sub-sequence". For example, if the sequence is 50 bits then the nessasary sub-sequence length would be something like 7 bits. If you detect the bits 1001110 for example, you would be able to determine the position in the sequence because that exact pattern only occurs at one place.
Before you think I'm asking about some useless theoretical nonsense, here's what I'm trying to do. I'm designing an arm for the front of my treasure hunter bot that needs to move a metal detector sensor pad back and forth through about a 160 degree angle. I want to make it possible for the arm to hit something and stop part way through the 160 degrees without causing any damage to the stepper, belts, etc. I need to be able to determine exactly where I am in the sweep range once I reverse the motor direction. I'm thinking I'll try using a semi circle "wheel" with 2 concentric rings of holes and a pair of cheap optical interuptor type sensors. The outer ring has a hole at every "position" and the inner ring has either hole or no-hole representing 1 or 0 "bits" in a ... a ... "Binary Ring sequence"????
I need the function that would give me the value 1 or 0 for a given posn in a sequence of length n... I'll settle for what to heck the real name for these sequences are.. I keep thinking "Lejoure sequence" or something but Google has _not_ been my friend the last few days. If you know a Usenet archive I remember answering "bingo" and used the word "Lancasterized" when someone finally gave me the name back 15 years ago in sci.electronics.design.
TIA
Post Edited (Hobbyist) : 5/14/2010 8:09:01 PM GMT
The idea is fairly simple. The sequence is simply a series of 1's and 0's of any specifed length. If I remember right there are only 2 for a given length and they are compilements (ie 1's and 0's are reversed). The whole point is that for each sequence it is possible to determine your position in the sequence from just a small "sub-sequence". For example, if the sequence is 50 bits then the nessasary sub-sequence length would be something like 7 bits. If you detect the bits 1001110 for example, you would be able to determine the position in the sequence because that exact pattern only occurs at one place.
Before you think I'm asking about some useless theoretical nonsense, here's what I'm trying to do. I'm designing an arm for the front of my treasure hunter bot that needs to move a metal detector sensor pad back and forth through about a 160 degree angle. I want to make it possible for the arm to hit something and stop part way through the 160 degrees without causing any damage to the stepper, belts, etc. I need to be able to determine exactly where I am in the sweep range once I reverse the motor direction. I'm thinking I'll try using a semi circle "wheel" with 2 concentric rings of holes and a pair of cheap optical interuptor type sensors. The outer ring has a hole at every "position" and the inner ring has either hole or no-hole representing 1 or 0 "bits" in a ... a ... "Binary Ring sequence"????
I need the function that would give me the value 1 or 0 for a given posn in a sequence of length n... I'll settle for what to heck the real name for these sequences are.. I keep thinking "Lejoure sequence" or something but Google has _not_ been my friend the last few days. If you know a Usenet archive I remember answering "bingo" and used the word "Lancasterized" when someone finally gave me the name back 15 years ago in sci.electronics.design.
TIA
Post Edited (Hobbyist) : 5/14/2010 8:09:01 PM GMT
Comments
www.taosinc.com/getfile.aspx?type=press&file=encoderdesign4b.pdf.
Attached is a follow-up paper that I wrote on the subject.
-Phil
As always seems to be the case (at least with me), nothing is ever easy : -) The depth of the theory here compared to my 8 year old and I drilling holes in a plastic wheel is striking... but it's all good... progress!
Thanks again bud.
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·"If you build it, they will come."