Comments for Project Blog

Comment on Collapsible Knitting Needle by ema

ema — Sat, 04 Feb 2012 15:32:21 +0000

Thanks Sandi! This design is easier to carry on a plane, easier to tote in a project bag and great for larger/heavier knitting! I’m off to order some!

Comment on Collapsible Knitting Needle by Sandi

Sandi — Sat, 04 Feb 2012 01:54:57 +0000

http://www.clover-usa.com/product/453579/3017/_/Takumi_Bamboo_Knitting_Needles_FLEX_%2820_INCH%29

Comment on Collapsible Knitting Needle by Sandi

Sandi — Sat, 04 Feb 2012 01:52:31 +0000

Ema – I have some of those! I think they’re from Clover, and are bamboo.

Comment on Collapsible Knitting Needle by Maryann

Maryann — Thu, 02 Feb 2012 20:32:24 +0000

I’m a knitter and a circular fan but I love your inventiveness with this! That’s what really matters.

Comment on Collapsible Knitting Needle by Pam Collins

Pam Collins — Thu, 02 Feb 2012 01:12:44 +0000

I used to use striaghts all the time & still find at times they would be the better alternative…Your invention would really get my attention!

Comment on Collapsible Knitting Needle by ema

ema — Wed, 01 Feb 2012 21:29:10 +0000

I prefer straights and can see the advantage to having needles that fold – occasionally…. I am the opposite of Keith – I have small hands and have created some very short needles (3-4″) that are great for knitting on your daily walk… For portability, I use interchangeable needles with a cord and end-cap. I’d LOVE to be able to purchase needles that are a straight/circular hybrid – that is, a 6-7″ needle with a cord on the end. I have designed them, but am not in a position to manufacture them…..

Comment on Collapsible Knitting Needle by Keith Neufeld

Keith Neufeld — Mon, 30 Jan 2012 20:09:23 +0000

For those of us with a handspan greater than an octave, knitting with circular needles is like trying to use toothpicks for chopsticks. Long, straight needles are the only way I can knit at any speed and without cramping up my hands. Of course, YMMV.

Comment on Collapsible Knitting Needle by curiositykt

curiositykt — Mon, 30 Jan 2012 18:52:34 +0000

Circular needles can knit more sizes of things, tend to get less tangled, do not involve accidentally getting needles caught on things like your clothes, do not involve needles poking people nearby.. all around they are pretty superior once you get the hang of them, I’m always surprised that people don’t start new knitters on them since they are considerably easier. And you can make anything flat or circular on them! I only use Double Pointed Needles and Circular now. Long ones are just too unwieldy.

Comment on Improving the Beginner’s PID: Direction by Brett

Brett — Mon, 30 Jan 2012 01:50:15 +0000

@wwwoholic thanks for the comments.

I’m not sure what you mean by inverting the output. Make it negative? This would work if I was using the velocity form, but just making the output -25 instead of 25 would not produce the desired effect. At the very least this would require some modifications to the initialization code. Another common way of doing the direction thing is to define error as PV-SP instead of SP-PV. Maybe that’s what you meant? Also, I’m not sure what you mean by “all over the program.” I make them negative in one place. other than that all the code is the same.

Your SampleTime point is well taken. I used placeholders for the tuning parameters because I foresaw a situation (adaptive tuning) where that function would be called repeatedly. With the SampleTime, I just couldn’t see a time were that would be called over and over, so I decided the error risk was minor, and not worth the extra (albeit small) overhead addition.

It’s on my list to go through the series and update both the overflow and reset windup code. With a day job and the ospid I haven’t been able to find the time.

Comment on Improving the Beginner’s PID: Direction by wwwoholic

wwwoholic — Mon, 30 Jan 2012 00:34:08 +0000

Wouldn’t it be MUCH simpler to invert output in one place instead of fiddling with constants all over the program?

And on related note, every time SetSampleTime gets called you introduce an error (however small) to constant values. Why not keep values set by user and calculate “running” constants as you do in SetTunings.

Also, it would be nice to see time overflow problem fixed on these pages. For those who do not read responses