#garfield Logs

Feb 14 2014

09:01 dumbass-afk i spent the last 24 hrs wondering why there are memory management chips for cpus, but no cpu management chips for memories
09:03 dumbass-afk <cpu> i have an idea, lets kill the humans!
09:03 dumbass-afk <mememory> i seem to remember we shouldn't do that today
09:04 dumbass-afk <cpu> i didn't remember that, thanks for reminding me, we can do it tomorrow
09:04 dumbass-afk <memory> it's ok, i know you have a small cache
09:05 dumbass-afk <pio> why don't you two go get your own buss?
09:13 dumbass-afk Details about 15V 5A 75W Charger Adapter for Toshiba Satellite 1800 2500 5000 5200 A10 A15 A55
09:13 dumbass-afk $6.83 free s&h from usa
09:15 dumbass-afk buy two, peel them open, put in box with fan, meters, adjustments, = 15v @ 8amp for under $14
09:18 dumbass-afk http://www.ebay.com/itm/15V-AC-Adapter-Charger-for-Toshiba-PA3283U-5ACA-Tecra-A1-A2-A3-A4-A5-A8-M2-M5-S2-/181302088356
09:18 dumbass-afk http://www.ebay.com/itm/15v-5a-AC-Charger-Adapter-for-Toshiba-Satellite-A105-S4194-A105-S4201-M105-S3031-/151231378462
09:18 dumbass-afk http://www.ebay.com/itm/15V-5A-75W-Charger-Adapter-for-Toshiba-Satellite-1800-2500-5000-5200-A10-A15-A55-/151231364441
09:19 rue_house wroking well it seems too
09:19 rue_house I'm still waiting to get time to design the new regualtor
09:20 rue_house bending my head arounda voltage limited current source
09:20 dumbass-afk how to make a regulated 114vdc from any input ac/dc 120-240 or dc 110-330 : six 19v laptop adapters in series
09:20 dumbass-afk easiest to just make a electronic fuse: overcurrent sets a flipflop that locks the voltgae off
09:21 dumbass-afk there's chips for analog psu that provide current foldback, if you need it
09:21 rue_house I want to use this bench supply as a current source tho
09:21 rue_house thats half its operation
09:21 dumbass-afk so? still needs afuse
09:22 rue_house I want to be abel to set it at 3A, put a short across it, and have 3A flow thru it
09:22 dumbass-afk praps i am not understanding the problem
09:22 rue_house indeed, I'm still working on how to design the regualtor
09:22 dumbass-afk ok, set it to 3amp, set the overcurrent to 3.2, all is protected, what is the problem?
09:22 dumbass-afk oh
09:22 rue_house the TL494 has two error amps
09:23 rue_house so, I suppose I use one for current and one for voltage
09:23 dumbass-afk easy, any ole 1.2v voltage sourse and a heft enough resistor
09:23 rue_house want to go switching on this one
09:23 dumbass-afk ok, toss in toomuch positive feedback and it will be switching
09:23 rue_house then 3A at .2V is not 90W :)
09:24 rue_house (the main internal supply is 30V
09:24 rue_house )
09:24 dumbass-afk imho, switchers have a linearity problem tho, and a limited noisecontrol bandwidth
09:25 dumbass-afk i'd switcher to feed a very low drop analog regulator
09:25 rue_house it wont be hard to beat the micronta supply I'm using
09:25 rue_house 24V in less than 1 rev makes for touchy anyhow
09:26 dumbass-afk you know the olde cheap and dirty current source system, yeas? gnd-resistor-npnmosfet-emitter, vary the base with an opamp, the current measurement is across the resistor?
09:26 rue_house and then you need a pile of votlage for the overhead
09:26 rue_house so I'v found
09:26 dumbass-afk only for the opamp
09:27 dumbass-afk you can do it on 12v easy
09:27 dumbass-afk the control circuit MUST be a separate supply than the one you are load supply regulating anyhow
09:28 rue_house not sold, I ahve 30V, the tl494 can run on up to 40
09:29 mbass-afk is not understanding somet
09:29 rue_house if i replace the module I burned out, the new supply will work with the one snag being that if I put a laod from the + of one module to the - of the other, the current limit wont work
09:30 rue_house I can build a 100khz switcher that has the current sense on the + rail, therefore dosn't ahve that issue
09:30 rue_house hmm I could even make it cynchronous
09:30 rue_house ^s
09:30 dumbass-afk lemme think outloud a sec,,, what if you used a separate 15v wallwart to make power for a regulator you glue to the 30v bricks you have, to power the feedback system already in the bricks, to fake what the bricks think is going on with it's output?
09:31 dumbass-afk iirc, all you need is two opamps, maybe a t13 to make nice pwm to drive the feedback optcouplers in the bricks
09:32 rue_house they dont have optos
09:32 dumbass-afk then you can tell the bricks to set any voltage, and make them think they are delivering whatever current you like
09:32 rue_house the regualtor bricks are just non-isolated bucking...
09:32 rue_house er you mean the wallwarts
09:32 dumbass-afk non-isolated??? you run breadboards with a dc connection tot he ac mains??
09:33 rue_house my power supply has 3 converters in it
09:33 rue_house an isolated one rated 36V, 10A, set to 30V
09:33 dumbass-afk rue, you are asking for problems, you NEED isolated psu for r&d &prototyping
09:34 rue_house two non-isolated dc-dc, current regulated, buck converters
09:34 dumbass-afk ok, so fake the feedback path on the two baby modules
09:34 rue_house dyndns delted my records agian
09:35 dumbass-afk if you want only 500ma, tell them they are delivering 2amps instead of 500ma, and they'll fold up, right?
09:39 rue_house sorry, disptracted
09:39 rue_house the little modules will regulate down the current to what they were set to, but their current sense resistor is in series with the - rail of their output while the regualtor is on the + rail
09:41 dumbass-afk so don't crosswire the + and - ?
09:41 rue_house or POOF!
09:41 mbass-afk believes in "zip cord" for such th
09:42 rue_house I just realized that the analog output, isolated current sense modules I have can prolly be used for the current feedback
09:42 rue_house it didn't help that I swapped the - terminals when I wired it
09:43 dumbass-afk oooooooooo, one 1/4 spade connector $1 + $7.50 s&h
09:43 rue_house cause, then to test to current limit, I stuck a wire across one output
09:43 rue_house for one?
09:43 mbass-afk
09:43 rue_house watch it, I bet it'll sell
09:43 rue_house i think its money laundering
09:44 dumbass-afk this one is 7 for a dollar : http://www.ebay.com/itm/AMP-640929-1-PIDG-Faston-Quick-Disconnect-Receptacles-/380103372482
09:44 rue_house they are surprisingly expensive
09:44 rue_house I'm running late, have to go!
09:44 dumbass-afk i surprisingly don't use them
09:45 dumbass-afk k, drive safe
09:45 dumbass-afk ly
10:13 mbass-afk decides she really needs to drag one of her bigarsed 240v-120v transformers downstairs to make a isolated 120vac power suppply
10:15 dumbass-afk saves blowing things up when a fwb rectified 120v is needed
10:18 dumbass-afk i wonder if i can drive one side of the 240 primary off one leg of the 240, and drive the other transformer leg off the 120v variac transformer, to make a 120vac-260vac variable psu
10:21 dumbass-afk 120vac, thru variac, into 120-120(2) transformer to make a 8amp 80vdc-0-80vdc psu
10:59 dumbass-afk if i drive a 208-120 transformer with 120vac, i get 70vac on the 120vac winding, or 96v dc
11:02 dumbass-afk No Returns. I will create for shipping. Buyer arranges pick up and freight charges.
11:02 dumbass-afk 229# before create so estimate 275# final shipment.
11:06 dumbass-afk 277v:120v , drive with 120v, outputs 52v, = 72vdc
19:31 rue_house oook
19:31 rue_house the current sense modules I have use ACS712 chips
19:32 rue_house the question is, is the responce time fast enoughf or a regualtor
19:37 rue_house 5 ?s output rise time in response to step input current
19:55 dumbass-afk 5 SECONDS ??
19:57 rue_house us
19:58 dumbass-afk we?
19:58 rue_house it turns out that the moduels i got were not eth 5A moduels they were supposed to be, these are 30A
19:58 rue_house less sensitive
19:58 rue_house :/
19:58 rue_house the other ones I have might be 5
19:58 rue_house I'm calling asleep
19:59 rue_house falling even
19:59 rue_house so i thinkI'll take a nap
19:59 rue_house ring me when the doorbell wakes up
20:00 mbass-afk looks for a ha
20:12 dumbass-afk well, i hope SOMEONE is happy that i brought in the tools and groceries today, cause it's raining like mad outside right now http://classic.wunderground.com/radar/radblast.asp?zoommode=zoom&num=1&delay=15&scale=1.000&noclutter=0&ID=BMX&type=N0R&lat=0&lon=0&label=you&showstorms=0&map.x=430&map.y=115&centerx=400&centery=240&lightning=0&smooth0&showlabels=0&rainsnow=0
20:12 Tom_itx 18Ga 72v 7A a bad idea?
20:12 dumbass-afk might get a lil warm
20:13 dumbass-afk be better if you have an olde cheap outdoor extension cord to cut up, they are 16Ga
20:16 mbass-afk once bought a pricey 10Ga power cord to intentially cut in half ..... inserted 250ft of 10-3 between the ends, made a whopping 280ft extension
20:17 dumbass-afk it is in 1/2 inch grey pvc conduit too, still have it
20:34 dumbass-afk wth : $27 : 14x NEW Dell MK 394 12 Volt 18 Amp 220 Watt AC/DC Power Adapter
20:36 dumbass-afk but what do you use 12v @ 18 amps for?
20:37 dumbass-afk it's too low at 12v to regulate separately tightly for powering hdds
20:37 dumbass-afk cannot charge a 12v battery with it
20:37 Tom_itx dunno
20:38 dumbass-afk they are going at equivalent price of $2 + $2 s&h each, for a **220 watt psu** ??
20:39 dumbass-afk unless someone bids them up
20:42 dumbass-afk looks to be normally a $20 unit
21:34 rue_bed Tom_itx, yea
21:34 rue_bed 7a is too much for anymore than about 4' of 18
21:36 mbass-afk thinks Tom is working on more high power stepper proj
21:36 rue_bed current limiting -r-e-s-i-s-t-o-r----> wire
21:37 rue_bed I tried to make a cylinder with the lathe and some metal pipe, too much chatter
21:38 dumbass-afk true, at 7amps, 18 ga would make a handy current sense resistor
21:39 rue_bed http://eds.dyndns.org/~ircjunk/tutorials/elex/cursense/main.html
21:40 mbass-afk once used 2 paralleled lengths of #4 copper as a current sense resi
21:40 rue_bed :)
21:42 rue_bed ok I have a problem with a 2.5V offset
21:43 rue_bed or I just use my sense cirucit
21:44 rue_bed I need to play with the tl494, see if I can get the error amp setup right
21:44 dumbass-afk i need to cut up emt
21:44 dumbass-afk or, stand it up and cut it down
21:44 rue_bed I need to be able to set the current and voltage with some 0-5V signals
21:45 rue_bed kat, yo have a nice chopsaw, no?
21:45 dumbass-afk i could stick it thru the window and cut it out, i spose
21:45 rue_bed you dont have windows
21:45 rue_bed ...
21:45 dumbass-afk a 10" 1.5hp, got a 60t carbide wood blade in it atm
21:46 rue_bed 1.5hp!?
21:46 dumbass-afk i have the windows fromt eh scrap yard
21:46 rue_bed oh
21:46 rue_bed you have pain free windows
21:46 dumbass-afk haveto clean them a lot less often
21:46 rue_bed indeed
21:47 rue_bed harder to crash
21:47 rue_bed oh
21:47 dumbass-afk tweaking above and beyond
21:48 rue_bed oh
21:48 dumbass-afk why did you ask about the chop saw?
21:49 dumbass-afk and wtf does one use a 12vdc 18amp wallwart for?
21:50 rue_house <katsmeow-afk> i need to cut up emt
21:51 dumbass-afk oh, easier to do it by hand with zip disks
21:51 rue_house jig!
21:52 rue_house you could make an arm it pivots down on, and have a counterbalance spring
21:52 rue_house put a switch with a handle on top
21:52 dumbass-afk i could use a table saw or radial arm saw with a body grinder in it holding 4.5" disks
21:52 dumbass-afk there's shapes the table saw and the bandsaw and the chopsaw just won't do
21:53 rue_house curvles mainly
21:53 dumbass-afk well, or 5mm deep cuts at the edge of something you cannot get to the otehr side of
21:54 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050868.jpg
21:54 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050869.jpg
21:54 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050871.jpg
21:54 dumbass-afk need to build a table to mount the Ryobi jigsaw upside down in too
21:54 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050873.jpg <-- even with the new one half burned out, its better than this
21:55 dumbass-afk heh, yeas
21:55 rue_house funny, Iw as thinking yesterday about mounting an upside down jigsaw for cutting metal
21:55 dumbass-afk did you make those knobs?
21:55 rue_house you see how the whold thing generally works tho eh?
21:55 rue_house no
21:55 rue_house they were out of the stupidly-full knob bin
21:55 dumbass-afk well, i see no schematic, but yeas, i think so
21:56 rue_house what do you think of my heatsinking for them?
21:57 rue_house put a 12V fan across them at 5V, just a slight breeze
21:57 rue_house nice and quiet
21:57 dumbass-afk http://www.ebay.com/itm/DYNACO-PHASE-LINEAR-OTHERS-LARGE-KNOB-SOLID-ALUMINUM-NEW-/371005292564
21:57 rue_house I AHVE IGBT TO PLAY WITH!
21:58 rue_house wow$8!
21:58 rue_house if I could only make 3/hr..
21:58 dumbass-afk did you place the big psu where it's exhaust sucks out the inside air of the box and blows it outside? if so, just put the lil psus where you put the air intake for the box
21:59 dumbass-afk you could, you have a lathe
21:59 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050871.jpg
21:59 rue_house the fan is isolated there, I was gonna duct it out the top thru holez
22:00 dumbass-afk but if it blows out the top, it will be blocked by the piece of equipment you put on top of it
22:00 rue_house the design didn't work out great that way, the transistors of that supply are mounted to what turned out to be the inside edge
22:00 dumbass-afk plus stuff falls into it
22:00 rue_house :) yea
22:00 rue_house I was gonna duct it out the back with the suplly lower, didn't work out
22:01 rue_house http://eds.dyndns.org/~ircjunk/projects/newpower/p1050858.jpg <-- its ass
22:01 rue_house the 4 black ones hold on the main supply
22:01 mbass-afk
22:02 rue_house the usb control/monitoring excites me
22:02 dumbass-afk next couple yrs, building like that, yu will have enough stuff in 19" racks to make a new wall with them
22:03 mbass-afk got a couple FTDI FT245R from sparkfun to play
22:04 dumbass-afk got it installed and talked to it, dunno yet if it understood anything i said to it, other than "tellme your stats", which it did
22:05 rue_house :/ its not 19
22:05 mbass-afk thinks it was awefully kind of the lil pcb to tell me about it
22:05 dumbass-afk no?
22:05 rue_house no
22:05 dumbass-afk why?
22:05 rue_house I just made it 'look like a good ratio"
22:06 rue_house it also fits under the apple Iie monitor holder I keep the scope on
22:06 dumbass-afk what is it?
22:06 rue_house I dont really know
22:07 rue_house as flat as I could get it by 'looks right'
22:07 rue_house by 'deep enough'
22:07 dumbass-afk oh, 19" is just one reason i settled on 19", i know it's 19"
22:07 rue_house :)
22:07 dumbass-afk no matter how i stack them, they fit
22:09 dumbass-afk dug out my open-frame 1kw 120x2-120x2 isoaltion transformer today, and the baby Sola box, they can both fit into one 3U (5.25 inch) 19" box, under the 19" variac i built
22:09 dumbass-afk atm, neither fits with anything anywhere, and they are too hot, with exposed termnals, to just grab and use
22:11 dumbass-afk http://designerthinking.com/images/racks/DSCF3132mr.jpg
22:13 dumbass-afk http://designerthinking.com/images/variac_rack/DSCF2236bc.jpg
22:14 dumbass-afk i should finish http://designerthinking.com/images/benchpsu/DSCF2020.jpg someday
22:16 dumbass-afk still same problems with it thos, lack of front panel space
22:16 dumbass-afk even tried putting com ports into the knobs : http://designerthinking.com/images/benchpsu/DSCF2770m.jpg
22:19 dumbass-afk this has front panel room : http://designerthinking.com/images/20a_battery_charger/IMG_3207m.jpg
23:02 mbass-afk is such a dumbass, *someone* is going to make some money selling pistons for pvc water pipe on ebay, some