#garfield Logs

Apr 03 2015

01:13 katsmeow-afk somehow, i am
01:22 katsmeow-afk 38 chapters of a .mil book
01:57 rue_shop3 maybe I better do the math
01:58 rue_shop3 2" dia
01:58 katsmeow-afk 67457562473576-=*/()\[]x~`^4573673765 = ?
01:58 rue_shop3 root@blackie2:/tmp# circle -d 2
01:58 rue_shop3 Radius is : 1.000000
01:58 rue_shop3 Diameter is: 2.000000
01:58 rue_shop3 Circumfrence is : 6.283185
01:58 rue_shop3 Area is : 3.141593
01:58 rue_shop3 Sphere area: 12.566371
01:58 rue_shop3 Sphere volume: 4.188790
01:58 rue_shop3 area is 3.14"
01:58 rue_shop3 at , lets say 25psi
01:58 rue_shop3 78Lbs
01:59 rue_shop3 k, thats too much for a simple pressure sensor
01:59 rue_shop3 nowonder I cant hold it back at just 10psi
02:02 katsmeow-afk warning, i should be sound asleep in 2 hours ago
02:02 rue_shop3 syringe is...
02:03 rue_shop3 25mm
02:03 rue_shop3 root@blackie2:/tmp# units 25mm inch
02:03 rue_shop3 * 0.98425197
02:03 rue_shop3 / 1.016
02:03 rue_shop3 circle -d .984
02:03 rue_shop3 Radius is : 0.492000
02:03 rue_shop3 Diameter is: 0.984000
02:03 rue_shop3 Circumfrence is : 3.091327
02:03 rue_shop3 Area is : 0.760467
02:03 rue_shop3 Sphere area: 3.041866
02:03 rue_shop3 Sphere volume: 0.498866
02:03 rue_shop3 calc .76*25
02:03 rue_shop3 .76*25 -->> 19
02:03 katsmeow-afk remeberere, typical syringes have random amounts of sticktion which may be severe
02:03 rue_shop3 19lbs force for the syringe, but its got a lot of stiction
02:04 rue_shop3 indeed
02:04 katsmeow-afk remeberere, typical syringes are such that if the rubber sticls badly, you can pull the plunger rightout of it
02:04 rue_shop3 I need an actuator for a force sensor for the air muscles
02:04 rue_shop3 I'm starting to think of just using a small airmuscle pulling on a spring
02:04 katsmeow-afk i tried drilling thru the rubber piece, and putting washers on both sides of it, and a steel plunger, no joy
02:05 rue_shop3 with a variable capacitive differential sensor
02:06 katsmeow-afk i think the best you can do will involve pvc pipe (in a steel shell for very high pressures)
02:07 rue_shop3 they only run a max of maybe 40 psi
02:07 rue_shop3 the mechas storage pressure is 100psi, regulated down to 60 iirc
02:08 katsmeow-afk or, use a thinwall DOM pipe
02:08 rue_shop3 ok, plan #..... I lost count....
02:08 rue_shop3 I was trying to think of something cheap and available thats bellowed
02:08 rue_shop3 but vauum cleaner hose is too ridgid
02:09 katsmeow-afk CV joint boots
02:09 rue_shop3 and I dont know how to seal it...
02:09 katsmeow-afk ball joint boots
02:09 rue_shop3 too big/heavy, but yea
02:09 rue_shop3 keep in mind 2" gave me 78lbs
02:09 rue_shop3 at 20 psi
02:09 katsmeow-afk jackhammer boots (you can get those on ebay even)
02:09 rue_shop3 ?
02:09 e_shop3 looks i
02:10 katsmeow-afk ball joint bots are only 2" dia and 1" tall overall
02:10 katsmeow-afk clutch slave cylinder boots
02:11 katsmeow-afk drum brake slave cyl boots (about 1/25 dia and 3/4 tall overall)
02:11 rue_shop3 oh, ooo
02:11 tsmeow-afk has no clue what size to guess
02:12 rue_shop3 http://www.ebay.com/itm/Ducati-Brembo-Rear-Brake-Master-Cylinder-Pump-Rubber-Dust-Cap-Cover-Boot-Seal-/331513030693
02:12 rue_shop3 hmmm
02:12 rue_shop3 your doing great
02:13 katsmeow-afk accel cable boot (you'll see them behind or to the side of the air valve or the carb)
02:14 katsmeow-afk parking brake cable boot , found at the end of the cable near the transmission, pointed towards the rear, for drum brakes only, i suspect
02:14 rue_shop3 http://www.ebay.com/itm/Lot-of-8-Dexter-TYPE-EZ-Lube-Trailer-Camper-Axle-Rubber-Grease-Plug-Hub-Dust-CAP-/230832667960
02:14 rue_shop3 "rubber dust cap"
02:15 katsmeow-afk looks exactly like the drum brake slave cyl boot
02:15 rue_shop3 indeed
02:16 katsmeow-afk $1.10 each, free s&h , and realy clean and unused
02:16 katsmeow-afk now, there's no hole in them to pass anything thru
02:16 katsmeow-afk what will you use them for?
02:17 katsmeow-afk that rubber weill rip before it drills
02:17 katsmeow-afk you canpunch it clean with a die tho
02:17 rue_shop3 only problem is that I need to spent less than $2.55 for all the parts for each axis
02:17 rue_shop3 I can make punchs on the lathe
02:18 katsmeow-afk yeasa
02:18 rue_shop3 you take a rod, drill a hole the size you want to punch, and taper the outside till there is a blade
02:18 katsmeow-afk i still dunno what these are for
02:18 rue_shop3 pressure sensors for the muscles
02:18 katsmeow-afk o
02:18 rue_shop3 you have to know the pressures on each side of the muscle to know if a movement should involve adding or removing pressure from one of both sides
02:19 rue_shop3 one or both sides
02:19 rue_shop3 the formula is the same as the joystick to tractor mixing I use for robots
02:19 katsmeow-afk you can use a disc cut from an old bike tire inner tube for that
02:19 rue_shop3 I did
02:20 rue_shop3 it resulted in a actuator that generates 78lbs at 20psi
02:20 katsmeow-afk 100 discs for $8 innertube
02:20 rue_shop3 __too strong__
02:20 katsmeow-afk o
02:20 rue_shop3 free tube, cause I can use one that leaks
02:20 rue_shop3 (just cut around the leaky bit)
02:20 tsmeow-afk
02:20 rue_shop3 and I can get a whole bike from the dump for $1
02:20 rue_shop3 (two tubes!)
02:21 rue_shop3 but... 78lbs
02:21 katsmeow-afk i used a plastic cap on a peanut can as a diaphram to measure air pressure
02:21 rue_shop3 I made some disks out of some flattened pvc pipe
02:21 rue_shop3 wait, what?
02:22 katsmeow-afk hmm?
02:22 rue_shop3 the plastic caps on bottles... they have a seperate seal peice in them still?
02:22 katsmeow-afk yeas
02:22 rue_shop3 so, if I cut out the middle of the cap to get at the 'diaphram'
02:23 katsmeow-afk but i used a *can* , like for 2lbs of salted boiled peanuts
02:23 rue_shop3 hmm, I dont know if that works
02:23 rue_shop3 ooh
02:23 rue_shop3 hmm
02:23 rue_shop3 I think its got some nonlinearities
02:23 rue_shop3 then again this would too
02:23 rue_shop3 computer remapping...
02:24 katsmeow-afk the lid was almost airtioght as it was, i taped it once, used a metal disc inside to reduce flexing on the switch contact area
02:24 rue_shop3 waaaaait
02:24 rue_shop3 waait
02:24 rue_shop3 dosn't the dielectric property of air change as the pressure goes up?
02:24 rue_shop3 hm, no thats crazy
02:24 katsmeow-afk moisture changes it much worse, i suspect
02:25 katsmeow-afk pressure *does* change it, hence vacumm sealed caps and feedthrus and scope probes
02:25 rue_shop3 so far I'm liking the properties of using a small air muscle thats tendon goes thru a linear position sensor and to a spring
02:26 rue_shop3 its not small, but none of the things we've discussed really are
02:26 rue_shop3 the pressure sensors are $5-$25ea on ebay
02:26 rue_shop3 it would be nice to have $4000 for this project
02:29 katsmeow-afk two pieces of unetched pcb, baloon tween them, air pushes the plates apart, changes the freq of an osc, you count the freq every .1 sec
02:30 rue_shop3 bellows
02:30 rue_shop3 hmmm
02:30 katsmeow-afk round plates, one at end of syringe, #2 held down againt it by spring in the cyl, baloon comes out the end
02:30 katsmeow-afk can't move much, and ideally, you prolly don't want it to move much
02:31 katsmeow-afk can maybe build the whole thing inside a 1/2 cpvc pipe cap
02:31 katsmeow-afk if not, then a 3/4 pvc cap
02:31 e_shop3 stares at the 1" cap on the f
02:32 katsmeow-afk heck, the #2 pcb and be *inside* the baloon even, as long as it moves up with the baloon (glue?)
02:32 rue_shop3 http://ruemohr.org/~ircjunk/tutorials/elex/ldvc/ldtc.html
02:32 rue_shop3 this is soemthing that works really nicely
02:32 rue_shop3 esp if you turn all those peices into pipe
02:33 rue_shop3 so aligment nulls out
02:33 katsmeow-afk use a 2" length of bike innertube, push it inside itself like a 1" bellows , one end is sealed with #1 pcb, the other with #2 pcb, attach spring, measure gobs of psi, or a couple
02:36 rue_shop3 thats part of the problem I dont know yet
02:36 rue_shop3 I suspect I need to measure over a range of 5 psi, but at a pressure offset of 10psi
02:37 katsmeow-afk adjust the wpring
02:37 katsmeow-afk slring
02:37 rue_shop3 pr
02:37 katsmeow-afk spting
02:37 rue_shop3 you mash the keyboard, I'm going to sleep on mine
02:37 rue_shop3 ggyullllllllllllll
02:38 katsmeow-afk your micronta looks lots newer than mine
02:39 rue_shop3 heh :)
02:39 rue_shop3 its my first multimeter
02:39 rue_shop3 I still regard it as the best one
02:39 rue_shop3 its fast, I dont know why new meters take so long to do a reading
02:40 rue_shop3 oh wait
02:40 rue_shop3 thats the new one,
02:40 rue_shop3 my old one is grey
02:40 katsmeow-afk i'd get the model # off mine, but it's hooked upto something and working, i don't wanna disturb it
02:40 rue_shop3 indeed
02:41 rue_shop3 my origional is a 22-188
02:41 katsmeow-afk note: 74LS is rated only to 30Mhz, and then it typically flatlines
02:41 rue_shop3 http://0303dba.netsolhost.com/micronta_volt_meter_lot5.jpg
02:42 rue_shop3 FAST autoranger
02:42 katsmeow-afk autorange can be a pta tho, mine has a "set range" button to lock it to one if i wanna
02:43 rue_shop3 that little grey one is so fast you prettymuch dont need to range lock
02:43 rue_shop3 its not like the new ones that take 3 seconds to work it all out
02:43 katsmeow-afk you do if you exepect to see 20mv, so you look up and it's showing 20v, and you didn't notice the 'm' is missing
02:44 rue_shop3 I'm surprised how hard it is to find a autoranger today, most meters are manual range
02:44 katsmeow-afk that autoranging "featuer" has bit me more than once
02:45 katsmeow-afk shifting decimal points too
02:45 rue_shop3 the thing that catches me on that meter, is that its defualt resistance units are k
02:45 rue_shop3 1.0 means 1k
02:45 rue_shop3 its got an ohmega it turns on for smaller values
02:46 katsmeow-afk i had a triplett that did that: 800 ohms was 0.80
02:47 rue_shop3 did I tell you I worked out how to do shoulders?
02:47 rue_shop3 discrete linkages
02:47 katsmeow-afk pics?
02:48 katsmeow-afk how to get a chinese seller to wake up : freeze the payment
02:48 rue_shop3 I have one tucked away somewhere
02:48 rue_shop3 I oopsed and gave good feedback for the wrong item, and they shipped me 1 instead of 10
02:49 katsmeow-afk ouch
02:50 rue_shop3 ma's beads, she gets so many that look so much the same I often get the feedback to the wrong seller
02:50 katsmeow-afk send all bad feedback one at a time, then you canblast out the same good feedback to the rest
02:54 rue_shop3 I made a new shelf in the shop
02:54 rue_shop3 I'm confused tho
02:54 rue_shop3 I have more space, but less
02:54 katsmeow-afk it's too low?
02:55 rue_shop3 lots of things fit under it
02:56 rue_shop3 its like anything else, in the shop, it takes a while to settle in after installation
02:56 tsmeow-afk
02:58 rue_shop3 I dont know if the length of an air muscle changes its strength
02:58 rue_shop3 will change the stroke
02:59 katsmeow-afk http://www.ebay.com/itm/ALLEN-BRADLEY-2090-XXNPMP-16S07-SER-A-NSFB/301123174231 <<== lol , they won't even open the box to check it, sale "as is"
03:00 rue_shop3 heh AB, expensive
03:00 rue_shop3 tommorow is a holiday
03:01 rue_shop3 I gotta go to work and shut down a fire alarm system
03:01 rue_shop3 *sigh*
03:01 katsmeow-afk now?
03:02 katsmeow-afk i should go lay down, see if i can sleep horizontally
03:03 katsmeow-afk but if i do sleep, i won't be seeing it happen
03:03 katsmeow-afk what a waste of thime that wouldbe
03:05 rue_house oh, ther was a article on how to make bellows out of silicone, I forgot about that
03:06 katsmeow-afk i wonder how difficult it will be to compute the turn on a 4 wheeled buggy with 4-wheel steering,, prolly still the same "find where one needs to point to out in space to make the desired movement, and turnthem all there" ?
03:07 rue_house vector thing
03:07 katsmeow-afk yeas
03:10 katsmeow-afk point one, find the radius of the turn, put the other wheels 90 deg to that radius, unless it's doing something fancy
03:29 katsmeow-afk http://www.autoblog.com/2014/01/27/evdrive-electric-utv-makes-zero-radius-turns-an-awesome-reality/
03:30 katsmeow-afk make it remote controlled by your home puters
04:12 katsmeow-afk "At 11 revolutions per minute, 6 tons of sewage per stroke per engine were pumped..."
04:13 katsmeow-afk burnerd 14 tons of coal per 24-hr day