#robotics Logs

Apr 23 2012

09:10 rue_house Corry's Law:
09:10 rue_house Paper is always strongest at the perforations.
12:50 katsmeow-afk hyperphacosorbitomyopicosis
12:50 Steffanx Yes yes
12:56 Steffanx wtf is that katsmeow-afk ?
12:56 katsmeow-afk a big word
12:57 katsmeow-afk plase look it up to find the definition you can most understand
12:57 Steffanx I didn't fully understand the wikipedia version
12:57 Steffanx but i guess google images is clear enough
14:00 SolarNRG Hi guys, I'm trying to make a sand cast of a 3D printed gear and I'm having trouble, all the sand keeps sticking to the teeth. Any ideas how I stop this problem?
14:00 SolarNRG Here is a video link of what I tried earlier this afternoon: http://www.youtube.com/watch?v=YoZHta8giAI
14:44 DanFrederiksen SolarNRG, talcum powder is sometimes used for sandcasting slip
14:46 SolarNRG I used it in this example
14:47 SolarNRG I sprinkled it in all directions
14:47 SolarNRG But the video above shows the outcome
14:47 DanFrederiksen and you need a smooth plug. if it has ridges that will obviously stick. you might have to do a 3 or 4 piece mold from the sides
14:47 DanFrederiksen but for a shape like that it has to be much better to just machine it from stock
14:48 DanFrederiksen you might be able to use a plaster mold instead. 3 or 4 piece
14:49 DanFrederiksen or maybe just two to slide it out
14:49 DanFrederiksen maybe
14:49 katsmeow-afk ever hear of "lost wax casting" ?
14:50 DanFrederiksen yeah you could do that too
14:50 furrywolf much better than lost cat waxing!
14:50 katsmeow-afk for real
14:52 DanFrederiksen SolarNRG, you want to cast alu?
14:52 Steffanx I guess have gave up on that :P
14:52 home hey guys :D
14:53 Steffanx Welcome home
14:53 home i got an accelerometer/gyro/temperature sensor XD
14:53 home going to start playing with it :)
14:53 moriarty home, why does an accelerometer have a temperature sensor too?
14:54 home it came with the gyro, no idea.. LOL
14:55 LoRez SolarNRG: you're horrible at filming... seriously, 1:38 of tryign to get the gear out and 12 seconds of holding it nearly off camera the whole time...
14:56 LoRez and what's wrong with sand being in the teeth? does it not come out?
14:57 moriarty lol LoRez
14:58 LoRez you're not going to be able to reuse your sand mold. you have to repack the sand around your form each time
14:59 SolarNRG yeah
15:00 SolarNRG But next time I do it, how can I ensure a nice copy of the teeth?
15:00 katsmeow-afk why are you screwing the eezeout tap in the wrong way?
15:00 LoRez well, how were the teeth fucked? we couldn't see them because they were off camera and covered in sand
15:00 katsmeow-afk you are turning it clockwise, it's threaded counterclockwise
15:01 SolarNRG Doh
15:01 SolarNRG :S
15:02 katsmeow-afk if you want it to bite in that hole and lift out, turn it the right direction
15:02 LoRez other than the sand, they look fine afaict
15:03 LoRez usually when you're taking metal parts out of sand molds they toss the sand and metal into vibrating troughs that have holes in the bottom and it pretty well disentegrates the mold
15:03 katsmeow-afk make a wax copy of the gear, pack the sand around it with a drain out the bottom, heat it to melt the wax out, or just pour the metal on top of the wax
15:04 katsmeow-afk LoRez, he didn't get to the casting part yet, he hasn't make a mold yet
15:04 SolarNRG I can't get hot enough to burn wax unless I do it in the microwave
15:04 katsmeow-afk you don't wanna BURN wax
15:05 katsmeow-afk LoRez, the white part he is pulling out is the platic piece he wasn't to make a mold of, but his sand mold material is sticking to the plastic, destroying the mold when he yanks it out
15:05 LoRez ah
15:06 Steffanx Ah, I thought i just made a new gear too :)
15:06 SolarNRG katsmeow right
15:07 katsmeow-afk SolarNRG, make a multi-part plastermold that you can make wax copies with, then leave the wax in the sand and pour the metal ontop, the wax drains out the hole in the bottom, you let it cool, then pour the sand out
15:07 katsmeow-afk the wax is cheap, the wax, sand, and plaster is reuseable
15:09 katsmeow-afk btw, why are you in favor of autism?
15:10 SolarNRG I'm not in favour of it, I raise money to raise awareness and support for families who have difficulty coping with relatives who suffer from autism
15:11 tsmeow-afk bets the relatives and family suffer more than those with au
15:12 katsmeow-afk i was just thinking that if one wants to end something, then one is usually against it
15:14 katsmeow-afk http://en.wikipedia.org/wiki/Lost-wax_casting
15:15 katsmeow-afk http://www.instructables.com/id/Lost-Wax-Casting/
15:16 katsmeow-afk http://www.submarineboat.com/lost_wax_casting.htm
15:16 SolarNRG I have autism and I don't like living with it as I can't get a job cos I don't know what to say and I can't behave propely
15:17 katsmeow-afk so if those doing the hiring would get over it, you'd have a job and be happy?
15:18 SolarNRG Well then there's the problem of my housing benefit getting cut off and running up rent arrears of a grand a month I have no hope in hell of paying
15:18 SolarNRG Then there's the problem of going private rental, I haven't the cash nor the references
15:18 SolarNRG Private won't accept housing benefit
15:18 katsmeow-afk private has a problem making too many damned rules
15:19 SolarNRG And even if I wanted a job, nobody's going to employ someone who failed their degree, who has mental health problems, a blank cv for 6 years, an ex convict in an area short of jobs anyway
15:19 katsmeow-afk what i am trying to say is it's them making the rules that make life difficult
15:19 SolarNRG yeah basically
15:19 SolarNRG the thing is they don't want the poor to get rich, because then the rich wouldn't have power anymore
15:21 katsmeow-afk right, so i am right, it's not the autism making life bad for you, it's all those without autism making rules againt you because they have a problem with it
15:21 Steffanx Sure katsmeow-afk ?
15:21 tsmeow-afk loks at Stef
15:22 SolarNRG sure
15:22 effanx loks
15:23 SolarNRG So I'm looking into other avenues, like making lots and lots and lots of metal gears
15:25 tsmeow-afk
15:26 Steffanx At least you try over and over again SolarNRG .. i think would've gave up on it :)
15:29 i-make-robots anyone in here succeeded at getting java to talk to an arduino board in OSX?
15:30 katsmeow-afk SolarNRG, i just got an email back from someone who has 100's of gears, asking about sizes and what gears mesh with what other gears. His answer was: 5/65
15:31 katsmeow-afk i have no clue what "5/65" means
15:32 katsmeow-afk Q : what sizes are your gears, and what gears mesh with what other gears?
15:32 katsmeow-afk A : 5/65
15:33 SolarNRG Well there is a metric denomition known as MOD
15:33 SolarNRG My existing solar reflector gears are steel MOD 1, my prototype 3d printed gears are MOD 3
15:33 SolarNRG Gears of different MOD cannot mesh
15:33 katsmeow-afk fine, how does that apply to 1000 different gears with no sizes or teeth count for them?
15:34 katsmeow-afk and what part of "5/65" is the MOD ?
15:34 SolarNRG You've lost me
15:34 SolarNRG www.beltingonline.com
15:34 katsmeow-afk the seller lost me
15:35 SolarNRG They have a lookup table for all kindsa gears there
15:35 SolarNRG I used their lookup table for an opnescad model of two gears
15:35 SolarNRG http://www.youtube.com/watch?v=VmG8_jvi1l8
15:35 SolarNRG Here they are
15:36 SolarNRG openscad modelling
15:37 katsmeow-afk but see, a page like http://www.beltingonline.com/gears-366/spur-gears-367/metric-0-5-to-8-mod-375/1-0-mod-spur-gear-517/delrin-416/ tells me nothing, they use the same picture for everything
15:39 katsmeow-afk then http://www.beltingonline.com/40-tooth-1-0-mod-delrin-500-spur-gear-ds10-40b-6546 sells ONLY 40tooth gears, but the selection chart lists 12 tooth to 80 tooth
15:39 SolarNRG dont bother with that click on one and theres a table
15:39 SolarNRG For each MOD of gear, there are discrete numbers of teeth that will work
15:39 katsmeow-afk http://www.beltingonline.com/80-tooth-1-0-mod-delrin-500-spur-gear-ds10-80b-6555 says the 80 tooth is ~$10usd , that's too pricey
15:39 SolarNRG And it'll tell you their outer diameter
15:40 SolarNRG Don't buy
15:40 SolarNRG Just take the numbers off the lookup table
15:40 SolarNRG That's what I did
15:40 SolarNRG Then I modelled it based on the numbers
15:40 SolarNRG Then I got someone to 3d print two gears for me
15:40 SolarNRG My gears are also stepped!
15:40 SolarNRG I.e. 2 gears in one
15:40 katsmeow-afk i dunno anyone with a printer
15:41 SolarNRG jezmy will print 4 you
15:41 katsmeow-afk what's a jezmy ?
15:41 SolarNRG jezmy from #reprap
15:41 SolarNRG HE printed mine
15:41 SolarNRG for like 30 quid for 2
15:42 SolarNRG Considering said gear made from steel would cost like 300 quid, it was a bargain
15:42 katsmeow-afk and then he'd haveto ship them to usa, that's gonna add up
15:42 SolarNRG Oh forget it then, find a US printer
15:42 katsmeow-afk riiight
15:42 SolarNRG Ask about on freenode, u'll find someone
15:42 katsmeow-afk i am on freenode, and i am asking
15:43 SolarNRG There's more than one channel
15:43 SolarNRG Try #reprap
15:43 SolarNRG #mendelmax
15:43 SolarNRG #openscad
15:43 SolarNRG #blender
15:44 tsmeow-afk logs those n
15:44 katsmeow-afk i need to see what torque can get from the project Tom is making before i can spec the gears to be made, just trying to find some for now, in case i need them
15:45 i-make-robots speaking of gears: http://www.youtube.com/watch?v=D_uAb-iEb_Q
15:46 furrywolf bbl, time for work
15:47 SolarNRG That's pretty awesome
15:47 SolarNRG Personally I like just giant spurs
18:40 katsmeow-afk http://www.projectprometheus.com/ https://www.weylandindustries.com/site/david
18:40 katsmeow-afk MODULE 8.0
18:40 katsmeow-afk INTRODUCING DAVID 8
18:40 katsmeow-afk He has been reimagined, reengineered and brought to life with better technological, intellectual, physical and emotional performance than ever before. Welcome to the eighth generation of cybernetic advancement. Brought to you by Weyland Industries.
18:40 katsmeow-afk With his new 99% emotional sensitivity level, David 8 can enter seamlessly into any environment and carry out an authentic human interaction. David 8 can understand and respond appropriately to even the most intricate emotional cues or subtly stated verbal commands. David 8 has valuable skills in manufacturing, finance, earth sciences and medicine, and he can become instantly competent in almost any other field.
18:41 katsmeow-afk He is polished, practiced, and efficient, by far the most advanced and human-like cybernetic individual on the market today.
18:41 katsmeow-afk David 8 is guaranteed to surprise you. He is extremely versatile, endlessly useful and his database of unique functionality is limitless. Unlike human counterparts, David 8 is willing to perform any task that he is assigned, without question or resistance. He will not flinch at even the most disturbing or seemingly irregular assignment, and he will dutifully persevere until reaching his final objective.
18:41 katsmeow-afk David 8 can be programmed to enter a default neutral state, devoid of emotional engagement. In this state, David 8 reacts to his surroundings using only his logic actuators and does not access his facial mapping sensors or other advanced emotion-response pathways.
18:41 katsmeow-afk His Motivation Sequences are bypassed in favor of a simplified rational response. This state can be useful for applications where traditional non-feeling cybernetic behavior is required.
18:42 katsmeow-afk With a fluid intelligence on the order of 1012 neurons or 200 petaflops, David 8 exhibits twice the neural net capacity of humans. The new sensory-data processor in David 8 combines perfect human reasoning with the most advanced cybernetic computing power.
18:42 katsmeow-afk An advanced polyurethane coating replicates the biological properties of human skin to exact texture, pliability and tensile strength. With a cadmium alloy endoskeleton, David 8�s frame can withstand over 1,000 pounds of compression force.
18:42 katsmeow-afk David 8�s unlimited memory capacity makes storing data from even the most complex models such as the one pictured possible. Additionally, with double the neural net capacity of humans, David 8 can memorize, store and retrieve data faster than ever before.
18:43 katsmeow-afk David 8 is fluent in all known languages through a dialectic implant and can infer the linguistic components of entirely new languages if encountered. Communication between humans and David 8 should feel entirely fluid and natural.
18:57 Tom_itx http://tom-itx.dyndns.org:81/~webpage/temp/cnc/psu/psu1.jpg
18:58 Tom_itx diodes are gonna mount on the bottom
18:58 katsmeow-afk any fan?
18:58 Tom_itx not sure if i'll need it
18:58 Tom_itx i have one i can use
18:59 katsmeow-afk calculate the heat dissipation in the diodes, i expect you'll need a small fan, you don't want the diodes and xformers heating the caps either
19:00 tsmeow-afk would deburr / round those holes where wires go
19:00 Tom_itx i plan to but it was late
19:00 Tom_itx it's just a fit test
19:00 Tom_itx and heatshrink around the wires
19:00 katsmeow-afk ok
19:01 tsmeow-afk easts some discount choco
19:01 katsmeow-afk had another fight with post aweful again, they bring out a package all the way from China, and then refuse to deliver it once it's out here
19:02 katsmeow-afk i haveto follow them back to town, thru town to the other side, and then they'll hand it to me
19:02 Tom_itx good you didn't have to follow them to china
19:03 Tom_itx my drivers should arrive this week
19:07 katsmeow-afk driver for what?
19:08 Tom_itx stepper
19:08 katsmeow-afk oh
19:11 tsmeow-afk gets slower and sl o w e r a n d s l o w
19:15 home so registers.. and register mapps..
19:15 home damn
19:16 home this acceleromater is so hard to read XD
19:41 rue_house accelerate faster when reading it
19:42 Tom_itx got the xfrmrs somewhat mounted
19:42 Tom_itx ^^
20:08 rue_house good stuff
20:10 Tom_itx packs will mound on the bottom
20:10 Tom_itx wires will be mostly hidden under it
20:11 rue_house katsmeow-afk, hah, good one
20:11 katsmeow-afk you mean David8 ?
20:12 katsmeow-afk i wonder if people aren't talking about it because they are scared of it?
20:14 Tom_itx possibly intimidated
20:14 rue_house hah
20:15 katsmeow-afk i guess it's not every day you find out a robot has been built that really is faster and smarter than humans
20:16 tsmeow-afk looks at rue and sh
20:17 rue_house so much to do
20:53 e_shop loads up a strand of ribbon cable wit
20:54 Tom_itx :)
20:54 Tom_itx need more 'fuse' lemme know.. i got plenty
20:57 rue_shop its not burning out
20:57 rue_shop its warma nd its dropping a bit of voltage, but its holding
20:57 Tom_itx how many wires?
21:05 zhanx http://www.dispatch.com/content/stories/science/2012/04/22/chasing-fusion.html not sure if that made it
21:17 rue_shop oops
21:17 rue_shop Tom_itx, just testing one
21:17 rue_shop I oopsed tho
21:18 rue_shop the current detectors I made dont wotk with the motor drivers
21:18 rue_shop difference in the way the grounds are done on the drive
21:18 rue_shop I think its not too hard to correct
21:18 rue_shop but I get to correct is 18x
21:19 Tom_itx i got lotsa 4 cond if you run low
21:32 Tom_itx rue_shop, how big a resistor would you use to bleed off 20,000 uf cap on power off?
21:32 rue_shop one time or continious attached bleed?
21:33 Tom_itx on a relay
21:33 rue_shop 50V?
21:33 Tom_itx to bleed them off on power off
21:33 Tom_itx yeah
21:33 rue_shop 500 ohms, 5W
21:34 rue_shop wire wound
21:34 rue_shop ceramic
21:34 rue_shop jukebox needs more rave
21:38 Tom_itx mmm i'll see what i can come up with
21:38 Tom_itx may need a good relay for that too
21:38 Tom_itx i got a good 500 ohm 175W one :)
22:01 rue_shop gee, buddy 3 has a significant weight just in jumper wire
22:02 rue_shop at 1.75A, the ribbon cable dosn't get significantly warm
22:29 rue_house well
22:29 rue_house I started 18 power cables, finished 3
22:30 rue_house also started 30 signal cables
22:30 rue_house have to modify the 18 driver boards
22:30 rue_house one controller board needs to be replaced (sidegrade)
22:31 rue_house need to make the battery backplane
22:31 rue_house design up the power inverter
22:31 rue_house by the time I'm done I might need bigger motors
22:36 Tom_itx ok uploading...
22:43 Tom_itx http://tom-itx.dyndns.org:81/~webpage/temp/cnc/psu/psu_bottom1.jpg
22:49 Tom_itx theBear
22:52 Tom_itx katsmeow-afk, you think 19,000�F may be enough?
22:52 Tom_itx that's all 9 of those
22:52 Tom_itx 19,800
22:52 katsmeow-afk yeas
22:52 Tom_itx not sure they'll all fit on there though
22:53 katsmeow-afk your diode blocls are not down flat on the channel, one is up on the radius, i think
22:54 Tom_itx i checked for that
22:54 Tom_itx i think it is
22:54 Tom_itx but i'll double check
22:54 Tom_itx i need paste under them anyway
22:54 katsmeow-afk use heatsink grease, use a lockwasher as a spring to deal with thermal expansion
22:54 Tom_itx it's got a cerated washer under the screw
22:55 Tom_itx may switch to a split one
22:55 katsmeow-afk that left-most waire hole to the xformer has some sharp corners
22:55 katsmeow-afk i use splits
22:55 Tom_itx i need to check it all over
22:55 Tom_itx just brought it in to look over
22:55 katsmeow-afk oem recommend cones, but those can be hard to find, and they aren't reuseable
22:56 Tom_itx i think it's the light on the diode packs
22:56 katsmeow-afk that left-most diode sure looks up on the radius to me, but i am not as close to it as you are
22:56 Tom_itx pretty sure they're flat
22:56 katsmeow-afk ok
22:57 Tom_itx i'll check again though
22:57 katsmeow-afk another thing, i got some of those metal box blocks off ebay, everyone had to be gone over with a flat file to remove burrs from the heatsink face
22:57 Tom_itx gotta clean up the holes and add heatshrink
22:59 Tom_itx i need to debur all the tapped holes anyway
23:01 Tom_itx figure out a fuse block and switch
23:04 katsmeow-afk fuses are good, no doubt, but you can add overcurrent to your drivers with prolly just a resistor, opamp, and transistor or two
23:06 katsmeow-afk fuses are a good thing too
23:06 katsmeow-afk most fuses take so long to pop, all the damage is already done
23:07 katsmeow-afk ever been in that situation, you're replaced all the smoked and exploded parts, so the electronics work again, but you're waiting on the replacement fues to arrive, and wondering why there were any fuese?
23:23 Tom_itx the drivers have a current limit resistor i need to add
23:24 Tom_itx they have reverse, thermal, overcurrent etc shutdown
23:27 delinquentme_ ok I * think * these two capacitors are interchangeable
23:27 delinquentme_ http://www.mouser.com/Search/ProductDetail.aspx?R=140-50N2-220J-TB-RCvirtualkey21980000virtualkey140-50N2-220J-TB-RC
23:27 delinquentme_ http://www.mouser.com/ProductDetail/Vishay/1C10C0G220J050B/?qs=%2fVYrxewl4mYopKLzL8PbyA%3d%3d