#robotics Logs

Mar 02 2014

02:38 rue_more halogen bulb... well its over 300c based on the way my solder pot works
02:39 Jak_o_Shadows Your solder pot is a thing of beauty.
02:39 rue_more I was verry amused it worked
02:39 rue_more and didn't blow up
02:40 rue_more and more amused every time it survives another freeze
02:40 rue_more which is every time so far
02:40 Jak_o_Shadows Why was the freezing an issue? Too fast a contraction stuffing it up?
02:41 rue_more I just expected that solder freezing around a halogen bulb would crush it
02:41 Jak_o_Shadows How fast does it cool down? Could the mass of solder have enough thermal mass/inertia to solidify slow enough that it doesn't break it?
02:42 rue_more it takes in the order of 15 mins to freeze
02:42 Jak_o_Shadows That's a semi-reasonable amount of time.
02:43 Jak_o_Shadows Tell you what. If you want it to blow, use a fire extinguisher on it (not the water type)
02:43 rue_more well the bulb wouldnt' survive that alone
02:44 rue_more a voltage source may be substituted for a resistor fed by a current source
02:45 rue_more w3hich comes in handy if your in need of a voltage soruce around an obscure reference point
02:46 rue_more http://2.bp.blogspot.com/-jylVVeGvqUU/UAXibEAaXXI/AAAAAAAAAHs/_C4t4ik2GDQ/s1600/Fig%2B3%2BCC%2BOperation%2BCircuit.bmp
02:46 rue_more like 3V off ground
02:47 rue_more but the best laid plan can come to a halt if your opamps common mode input only goes to vcc-1.5V
02:49 rue_more and it can only take a 30V power rail
02:49 rue_more and your power supply goes to 30V
02:53 Jak_o_Shadows http://youtu.be/k5542wp15hw?t=1m14s is an interesting design.
02:53 rue_more yea, suddenly everyones using it
02:54 Jak_o_Shadows Well, Omni/mecanum wheels are expensive, and not actually that great in the other direction.
02:55 rue_more balancing ball robots
02:55 rue_more the ultimate in unidirectional
02:55 Jak_o_Shadows They are a fun control task.
02:55 rue_more then do a balancing cube robot
02:56 rue_more the other end of the scale all togethor
02:57 rue_more hahaha
02:57 rue_more I just designed a lamppost toolholder for my lathe
02:58 Jak_o_Shadows I think I remember seeing that. Store a bunch of energy in spinning disks, then brake the disks. It still wants to move, so it flips it
10:43 GuShH_ rue_more: the difference with your solder pot is you enclosed the halogen, and you are using a lot more energy, this is free air, 25W, mostly dissipated outwards
10:44 GuShH_ The motor does heat up close to what you mentioned, but it's not in contact with the oil by 10-15CM
10:44 GuShH_ the bowl is sealed, and there's not enough temperature or a proper ignition source to ignite any possible volatile fumes
10:44 GuShH_ you should know better.
10:45 GuShH_ But if you can find cases of fires started by these lamps, I'll reconsider your concerns.
10:45 GuShH_ It shouldn't include mishaps by pets or roaming retards.
10:45 GuShH_ Namely captive flybacks and the like.
10:46 GuShH_ Either way, 30W oil is too thick for this, I need thinner mineral oil. Other than that, it's working.
10:46 GuShH_ But it's NOT a design I would use for the lathe oil pump, should I choose to make my own.
10:47 GuShH_ I know the tiny pond pumps use the same centrifugal setup, I don't like them either which is why I haven't bought one yet.
10:48 GuShH_ I was thinking about using a drillbit as the screw for a simple screw pump (low pressure) however it may prove difficult to support the bit on both sides, and machining HSS is a pain in the arse.
10:48 GuShH_ so if anything I would cut a screw from aluminum rod...
10:49 GuShH_ I think the benefit for a screw pump is that it doesn't churn up the oil, so less air is introduced
10:50 GuShH_ And for low pressure, the tolerances shouldn't be too hard to reach. Damn, that centrifugal pump had NO concept of tolerance, it was all wiggly and you could fit a coin in all the gaps...
10:50 GuShH_ but given it's simplicity it means you can submerge it without having to worry about seals, just use a long shaft.
10:53 GuShH_ and since you're pumping oil, you don't have to worry about lubrication
10:54 GuShH_ of course we assume the oil is filtered first.
10:54 GuShH_ and strained before, plus a magnet.
11:19 GuShH_ better idea... delrin impeller!
11:19 GuShH_ well, screw.
12:40 rue_more dont let me get you wound up about it if your not worried
13:27 Agent86 hi all
13:40 rue_more high
15:04 GuShH_ rue_more: huh?
15:04 GuShH_ rue_more: surely tight tolerances are only required for high pressure applications
15:05 GuShH_ I can get it pretty good, but I don't want to waste material.
15:05 GuShH_ already got the blank shaft and both ends turned down to take the 608 bearings
15:05 GuShH_ nice tight press fit
15:05 GuShH_ also the "barrel"
15:06 GuShH_ need to turn the screw portion, fittings, etc
15:07 GuShH_ we'll see if it works, otherwise it should teach me a thing or two about screw pumps surely
15:07 GuShH_ I know the gap between the screw and the housing / barrel needs to be as small as possible, but a bit of leakage is OK with this thick fluid
15:08 GuShH_ what I don't know is how short I can make it
15:09 GuShH_ is screw length an important variable? does it determine how much pressure it's able to build up? or does it not matter with positive displacement pumps?
15:19 SquirrelCZECH it matters I would say
15:19 SquirrelCZECH :)
15:20 rue_more http://www.ebay.ca/itm/DATA-COMM-32-2024-WH-2-4-GHZ-COAX-WALL-PLATE-WHITE-/231154862833
15:20 rue_more ya know, I'm pretty sure I can get those for $1 locally
15:20 rue_more money laundering?
15:21 rue_more all their prices are crazy
15:28 MrCurious masked soldiers bearing no flag patches in the ukrane... i think we are witnessing the rise of COBRA...
15:33 GargantuaSauce http://www.youtube.com/watch?feature=player_detailpage&v=-TKBG3ZRAyY#t=49
15:39 ferdna when building your own arduino... you need a 25v, 35v or 50v 10uf decoupling capacitor for your power supply?
15:39 MrCurious putin should totally have opted for cobra themed uniforms
15:40 MrCurious have a sense of humor and style when invading another country to blunt the response
15:40 MrCurious like clown themed uniforms...
15:40 MrCurious so reporters can ask "just who are these killer clowns, and where they from? space?"
15:40 MrCurious or would that cross the line into taste based war crimes...
15:54 ferdna when building your own arduino... you need a 25v, 35v or 50v 10uf decoupling capacitor for your power supply?
15:59 GuShH_ ferdna: 10kV capacitors
15:59 GuShH_ 100W resistors
15:59 GuShH_ 200KA power supply
16:00 GuShH_ 1 cricket, alive.
16:00 GuShH_ It's called a Foundrino.
16:01 GuShH_ Have your own foundry in a tupperware at home!
17:45 rue_shop2 oh yea, I have to find a drum for a tumbler
18:03 eadthem are there any other good places to get miter gears than stock drive products
18:04 eadthem i need 1 side .375 bore other .250 bore
18:04 eadthem both with set screws or other locking method
18:04 eadthem the 375 i could use locknuts on the 250 is just rod
18:05 eadthem stock drive is charging about 10$ for each of 4 gears i need
18:05 eadthem but they have no set screw
18:08 rue_more to finish the tumbler I need to use the tablesaw
18:08 rue_more to use the tablesaw I need to set it up on the deck
18:08 rue_more to make space on the deck I need to build the new shelvs in the shop
18:10 eadthem mmm sounds faimilar
18:11 eadthem to put in the LED lighting i shuld build the kitchen cabnets first else ile have to do it agan
18:11 eadthem to build that i have to finish building my tablesaw
21:20 eadthem anyone have some 8020 tube like some 1x2 or 1x3
21:21 eadthem i need mesurements on the internal dimentions of the tube
21:21 eadthem im trying to mount a 3/8 inch coupler nut inside it to mount to a slideing beam
21:21 eadthem to use as a leadscrew
22:48 rue_shop2 building new bench power supply
22:48 rue_shop2 high side current sense, where "high" is from 0 to 30V
22:49 rue_shop2 so, the first thing is a dc-dc supply that sits on the rail to generate 9V for the sense amps
22:49 rue_shop2 an opamp for the current sense, and a fet current reflector
22:49 rue_shop2 but I did it,
22:50 rue_shop2 its gonna be a much larger circuit than I was going for
22:50 rue_shop2 but I used the new supply (which apparently only wants to go to 3.85 or the 5A its supposed to do) to test it, and its good
22:53 rue_shop2 then I get to deal with the synchronous buck converter, I might not go synchronous tho
22:53 rue_shop2 dosnt' suit discontinious mode well
22:56 rue_shop2 gizzard, my 16 bit dacs are gonna arrive by the time I get the regulator sorted out
23:04 rue_more and their comming from china
23:04 rue_more I ahve much software to sit down and figure out
23:41 rue_more kitty litter! arg the agony
23:43 MrCurious that needs to be automated
23:44 MrCurious suppose if i can make a cnc, i should be abe to make a kitty litter scooper
23:44 MrCurious hoppefully one that wont eat cats
23:45 armyofevilrobots Obtains sentience, eats cat anyways.
23:45 MrCurious well yeah, it has a shitty job
23:46 armyofevilrobots http://image.legios.org/var/albums/random/0.jpg?m=1366637391
23:46 armyofevilrobots :D
23:48 MrCurious thank you! i will be here all week