#garfield Logs

Feb 10 2014

00:16 rue_shop3 cartoon: park setting, two flock of birds in a tree looking down at three stones on the ground, one bird says to the rest, "there's three of them and 40 of us, troops, your odds of survival are good"
00:17 rue_shop3 \two\\
00:51 TELunus http://i.imgur.com/Dm36WIN.png http://i.imgur.com/rhvbICp.png http://i.imgur.com/yTP1he4.png
00:51 TELunus A little WIP i've been toying around with since this morning.
01:05 rue_shop3 interesting, hexapod?
02:01 dumbass-afk i cannot sleep
02:07 rue_shop3 then dont
02:09 rue_shop3 http://xkcd.com/203/
02:13 dumbass-afk but i are tired
02:15 dumbass-afk yeas, dreams can get wierd, like waking up in bed at 6am after you thought you had been at school for 2 hours already, and now you haveto re-live the last 4 hours that you thought you were living
02:19 rue_shop3 last night I dreamt that I was with an alien in his ship trying to get away from earth, every time we flew away the ship auto-relanded, we couldn't work out why, but knew that we didn't have too many tries till we were out of power
02:19 rue_shop3 sit by and I'll post you images of my new power supply so far
02:20 dumbass-afk did you try confusing it's nav system so it would land on the moon? that takes a lot less power to lift off from, as you know
02:27 rue_house there were issues knowing what was going on, it was till after a while looking out a window before we noticed we were down again and not moving
02:27 rue_house we even tried watching during takeoff and everything seemed fine till we looked away
02:28 dumbass-afk here Hal, play flappy birds and we'll mind the takeoff this time, ok?
02:31 rue_shop3 hmmm how to take 35V down to 5V for some leds and a microcontroller
02:31 rue_shop3 or, should I just take it from the 120 with antoher adapter supply
02:31 dumbass-afk yu need a chip known as a "30v remover"
02:32 rue_shop3 I dont have any little smps boards in that range
02:32 dumbass-afk use a 7805, with a 15v zener to drop the input voltage
02:33 rue_shop3 I'd like to use an smps
02:33 dumbass-afk you can cheat and put a big ole TO-3 can in front of the lil 7805, let the TO3 can servo the incoming voltas down to just 8v to feed the 7805
02:33 dumbass-afk ok, use a smps
02:34 rue_shop3 one from an old printer might work
02:34 rue_shop3 they used to put like 22vac into them
02:38 rue_shop3 hmmmm smaller....
02:39 dumbass-afk didn't Tom make some smp for 5v?
02:40 rue_shop3 I think so yes
02:41 rue_shop3 I got a bunch of these cigerette lighter ones for cars
02:41 rue_shop3 they use
02:41 rue_shop3 34063
02:41 rue_shop3 (M)
02:42 rue_shop3 Operation from 3.0 V to 40 V Input
02:42 rue_shop3 hmmmm
02:43 dumbass-afk protect the hell out of the input, the motors will be dumping flybackpulses intoit
02:43 dumbass-afk a small RC should do it
02:44 dumbass-afk it matters, rue, my Yamaha mixer has 100ohm and 100u caps on the incoming power to every board in the thing
02:45 dumbass-afk buss driver chips are made with 25 ohm resistors in them, using the buss capacitace as the C
02:52 rue_shop3 I was wondering if I should do some sorta output high clamp
02:53 mbass-afk doesn't
02:55 dumbass-afk going to go lay down again
03:15 rue_shop3 usb chargers done make good 5V powr supplies, they seem to be designed abrout the 5.2V mark
04:21 rue_shop3 yay, primary power works
04:30 rue_house kat, are you back up yet?
04:34 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050856.jpg
07:14 Tom_itx 10� F Light Snow
07:31 rue_shop3 we got a dusting of snow too
18:03 TELunus Ya, hexapod. But with all the servos closer to the base than a lot of designs I've seen.
18:03 TELunus Also, servos are expensive.
18:04 TELunus 1 servo/dof * 3 dof/leg * 6 legs = too much money
18:14 dumbass-afk rue, very pretty, nice how the 19" rack works so well, eh?
18:45 dumbass-afk TELunus , at $2 per servo, is $36, what you need is mechanical amplifiers so the cheap plastic servos do the electonics interface andd the mechanical amplifier does the grunt work
18:48 dumbass-afk oldtyme Ford power steering was a bolt-on amplifier for mechanical steering gearbox, the regular pitman arm operated a shuttle valve at the end of a hydraulic cylinder, that assy was in effect a mechanical amplifier
18:49 dumbass-afk the pitman arm pushed at 5 pounds, the hydraulics pushed at 500lbs
18:50 dumbass-afk grab ye one of those cheap 120psi 12vdc truck tire air pumps, control with a t13, let it pump oil instead, feed to 1/2 inch pvc (good for 300psi) cylinders
18:52 dumbass-afk yeas, there's a price increment hump to get over, but your lil hexapod wouldn't be that much larger, and could carry a car around
18:52 dumbass-afk we need someone like Tom to make the valve body for us
19:17 dumbass-afk http://i.dailymail.co.uk/i/pix/2014/02/07/article-2553739-1B45DCF200000578-148_634x918.jpg
19:24 rue_shop3 I blew up one of the buck modules
19:24 rue_shop3 *already*
19:26 dumbass-afk ouch
19:33 rue_shop3 the current control is all wrong
19:33 dumbass-afk o
19:33 rue_shop3 its not a linear cutback, its a shutdown-while-overloaded
19:34 dumbass-afk rue, have yu ever opened one of those sg90 servoes, filled it full of oil, and tried to use it?
19:34 dumbass-afk ummm, yea, overheat while current limiting is a common failure mode, it's why current foldback was invented
19:36 dumbass-afk the 78xx/79xx are thermally protected, they don't stop providing current into a short until they have overheated and shut down
19:37 rue_shop3 I dont get that, cause I was playing with them before and i'm sure I was able to regulate it down to like 20mA and run an led direct
19:37 rue_shop3 I suspect I may have to make my own buck regulator
19:38 dumbass-afk err,, did you pop a cheap regulator or the pricey 35v 30amp jobs from China?
19:38 rue_shop3 the little one, it was just a few bucks
19:39 rue_shop3 my confusion is over the fact that, the pretest checked out
19:39 dumbass-afk btw, this is one example of why i have built my own whatever-it-is power systems instead of buying them and using them as advertised
19:42 dumbass-afk those lil 15v laptop psu will have a softstart input, separate current and voltage regulators and temp sensors on their outputs, i am simply not using them as advertised
19:46 rue_shop3 indeed, I was skeptical, but I did tests when I got them and everything looked ok
19:46 rue_shop3 *but* if I do build my own, it gets around the issue of not having digital control
19:47 rue_shop3 I can make sure all the control voltages are 0-5V
19:47 rue_shop3 then i can operate it with encoders on the front and over serial (usb adapter incorperated)
19:48 rue_shop3 meaning that I can watch things like output power per channel on the computer
19:49 rue_shop3 its gonna make this take longer to build than I was hoping for
19:49 mbass-afk nods, R&D can take a lot of
19:50 dumbass-afk i just emembereded something i forgot to get done today: draining another 200 gallons from the outside tank to the inside before it frezzes tonite
19:51 dumbass-afk i prolly have enough inside already, the problem is the outside pool-tank is already overfilled, and any precip may overflow it
19:53 rue_house ya know, if I'd mixed the -+ from the modules it might do this
19:53 rue_house surely I didn't do that
19:54 dumbass-afk err,, wouldn't it have blown up when you powered on instead of waiting for you to short it?
19:55 rue_house they sense the current off the - rail of the output
19:55 rue_house if the + of one module was grounding thru the - of the other, it couldn't turn cut back the power
19:56 rue_house its a bug I didn't see
19:56 rue_house before
19:56 mbass-afk got
19:56 rue_house two modules
19:56 rue_house if you put a load between the - of one and the + of the second, there is no current control
19:57 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050862.jpg
19:57 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050863.jpg
19:57 dumbass-afk there's also no power
19:57 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050867.jpg
19:57 rue_house there is, thry have common input
19:57 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050868.jpg
19:57 rue_house the outputs are not isolated
19:57 dumbass-afk err,, you had two input bricks in series, and shorted them?
19:58 rue_house no
19:58 rue_house those two modules
19:58 rue_house inputs are parallel 30V
19:58 rue_house on the outputs of them, there is a .05R in series with the - output
19:58 rue_house thats how they sense current
19:59 rue_house if you take the + from module A and the - from module B, module B senses the current and module A controls it, but they dont talk, while module B says OH MY DOG! TOO MUCH POWER! module A keeps happily delivering it
20:01 dumbass-afk are the outputs of module A and B in series?
20:02 rue_house no, they are the two outputs of the power supply
20:02 dumbass-afk so you cross-wired the psus?
20:02 rue_house I'm saying if you put a laod from module A + to module B -
20:02 rue_house yea
20:02 dumbass-afk you cannot do that
20:02 rue_house I may ahve
20:02 rue_house yea
20:02 rue_house I didn't think of that before
20:02 rue_house I'm gonna go check my wiring
20:02 dumbass-afk if you do, it's likely somethingmay blow up
20:03 dumbass-afk i'm gonna go open water valves and things
20:03 rue_house k
20:05 rue_shop3 crap, thats what happened, I mixed up the wires
20:05 rue_shop3 the -'ives are reversed
20:10 rue_shop3 they have another thing tho, the current limiting kicks out with the voltage all the way down
20:44 dumbass-afk usps is refusing to deliver another package, that's 3 so far this year
20:50 rue_shop3 what do they say?
20:51 rue_shop3 (how do they refuse)
20:51 dumbass-afk this time they saw they want delivery confirmation
20:52 dumbass-afk last time they said i didn't exist and then said a bubble envelope the size of a small potato would not fit into a mailbox with a 6x7 inch opening
20:56 rue_shop3 its possable they were told to not give it up without a signature, its a delivery option
20:56 dumbass-afk it's not checked for signature
20:56 dumbass-afk i didn't pay for signature
20:57 dumbass-afk plus, i paid to have the package delivered to the address on the package, it wasn't delivered
21:00 rue_shop3 hmm
21:05 rue_shop3 wow I make one hell of a mess when I'm building a project
21:05 dumbass-afk congrats
21:07 dumbass-afk weatherman tonite pointed at the Mississippi at Arkansas, and said "it's snowing on the Mississippi delta", but it wasn't, it was snowing in Arkansas where he was pointing
21:11 rue_shop3 hsahaha
23:19 rue_shop3 http://www.ebay.ca/itm/Stainless-Steel-M3-X-5-A2-Hex-Nut-18-8-304-25-Pack-/171128600871?pt=LH_DefaultDomain_2&hash=item27d80f3927