#robotics Logs

May 31 2014

00:38 rue_shop3 1.4 degrees
00:41 GargantuaSauce wat
00:48 rue_shop3 a bingree
00:48 rue_shop3 a bingree is 1/256 of a rotation
00:55 GargantuaSauce wouldn't bytegree or debyte be a better name?
00:55 GargantuaSauce just using the base for the name is pretty ambiguous
00:55 GargantuaSauce i'd say 16 bit representations are at least as common
00:56 GargantuaSauce bytian
00:57 GargantuaSauce and really, go ieee754 or go home :V
01:01 GargantuaSauce man i want to experiment with making magnetic ball joints but i cant find all the ~1cm steel balls i had
01:01 rue_shop3 wholy ***
01:01 GargantuaSauce i had one of those magnetic polyhedral ball+stick toys but cant find the damn thing
01:02 rue_shop3 I have two "T+R D7218" absolute encoders, I was gonna use one on my robot for wheel postion, but while digging thru the internet for data, I cound out its worth like $400
01:02 rue_shop3 maybe I'll sell it instead...
01:02 GargantuaSauce good encoders are so stupidly expensive
01:02 GargantuaSauce use them for the hip or knee joints on your mech
01:03 GargantuaSauce hip is probably the most important to have super accurate
01:03 rue_shop3 http://www.plccenter.ca/en-CA/Buy/T-AND-R+ELECTRONIC/D7218
01:03 rue_shop3 http://www.ebay.ca/itm/T-R-ELECTRONIC-D-7218-USPP-D7218-/310847572481
01:03 rue_shop3 I could make an encoder for myself
01:04 rue_shop3 spend the $400 on other things
01:04 rue_shop3 but I still cant find the damn pinout
01:09 rue_shop3 hmm
01:33 rue_shop3 that sucks, it uses HV outputs
01:33 rue_shop3 hmmm
01:34 rue_shop3 suppose I could still use sine/cosine pots for absolute positioning
01:48 rue_more need to make some warped sine tables
02:18 just_corey greets
02:30 GuShH rue_more: you should get some cobalt bits... plain hss just doesn't cut (!) the mustard specially on interrupted cuts, I just abused a cobalt roughing tool and no damage at all, the plain hss would have lost the edge or the radiused tip.
02:30 GuShH slightly harder to grind and hone, but it's worth it
10:39 rue_more aka solid and not plated?
10:48 Tom_itx freezer only gets down to 27F now
10:48 Tom_itx compressor?
10:48 Tom_itx low freon?
10:48 Tom_itx low freon = leak
11:17 rue_more mine died too
11:17 rue_more carefull, compressors running 24/7 will cause large electricity bill
11:18 rue_more adding ascii characters to number interpretation for my command line calculator wasn't as easy as I thought
11:28 rue_more if I have to scape a single equote for a character in c, do I have to escape and escape?
11:28 rue_more I think its '\'' and '\\' respectivly
11:47 GuShH Tom_itx: solved your freezer issue?
11:47 GuShH I would recommend you clean the coils first.
11:48 GuShH -then- figure out if it's low refrigerant, stuck valve or what.
11:48 GuShH Not an expert in HVAC but I've fixed mine a couple times, enough to know the basics and not to pay some bananaboy to do it for me.
11:48 rue_shop3 I wonder if regrigerant lights up as easy as propane
11:48 GuShH some newer mixes are butane-propane and some other crap
11:49 GuShH with uv tracers in some of them
11:49 GuShH mine is R22
11:49 GuShH you know why I fix it twice already, because I don't want the new crap.
11:49 GuShH I know it won't last 30+ years.
11:49 GuShH heck it won't get past the warranty period
11:50 GuShH I did an icemaker conversion on it ... just missing the solenoid :(
11:52 GuShH it's just an insulated box with a closed circuit heat pump, as always they want you to believe it's harder than it really is. you actually don't need a gage / manifold set to recharge it if you know what you're doing
11:52 GuShH anyway my bet is his coils are dirty.
11:53 GuShH worse than a low charge is an overcharge, so make sure it's all clean to start with
11:53 rue_shop3 mine has no open coils
11:54 GuShH mine are on the bottom, you have to remove a couple access panels
11:54 GuShH inside, there's also a panel to be removed
11:54 GuShH but of course, inside you don't get dirt and hair buildup heh
11:54 GuShH I metered the amount of refrigerant by looking at the frost pattern on the coil
11:55 GuShH mine has a recharge valve, so it's common for them to very slowly leak over time
11:55 GuShH I added R22 until the entire coil was covered in frost, uniformly. you don't want the frost to start showing up near the compressor though, that's an overcharge
11:55 GuShH I know since I did it the first time, compressor wouldn't start after that.
11:56 GuShH Hey how else would you learn!
11:57 rue_shop3 whats the free air speed of an opened up, unlaiden tiny13? 4Mhz?
11:57 GuShH rue_shop3: it's neat how the evaporator coils instantly begin to frost up
11:57 ShH hands Tom_itx a brush to clean the condenser c
11:57 rue_shop3 if you can even get at them
11:57 rue_shop3 I think thats only valid for fridges
11:58 rue_shop3 never seen a freezer with an open evap coil
11:58 GuShH you should be able to access
11:58 rue_shop3 I'd have to tear the sides off mine
11:58 GuShH one way or another there should be access
11:58 GuShH but maybe it's the freezer on his fridge that's showing high temp issues
11:58 rue_shop3 not if their built into the walls
11:58 ShH doesn't like disposable applia
11:59 GuShH older stuff was meant to be serviced properly
11:59 rue_shop3 if the t13 had a uart, I'd be able to get 4800 baud from it
11:59 GuShH my fridge for instance has rear access panels with double gaskets and thick foam insulation that can be removed, for electrical access.
11:59 GuShH sure it's a bit of an energy loss, but you can actually service it.
12:00 GuShH it just costs more to make them like that, so they don't.
12:00 GuShH rue_shop3: z80 adventures?
12:01 rue_shop3 I need to have a tiny13 push data over a serial link from an encoder on a wheel
12:01 rue_shop3 last nights z80 stuff went well
12:03 GuShH oh god reading on skepticals talking trash about the ZX45 mill not being able to bore a cylinder head.. their points are ridiculous it's clear they're armchair machinists.
12:03 GuShH ""As the single point tool rotates, the machine will move and deflect as the backlash in the ballscrews and gibs is constantly taken up. Conventional engine boring machines are massive with massive quills and are designed to handle this. A benchtop hobby machine is not. ""
12:03 GuShH you ALWAYS lock your table, ALWAYS.
12:03 GuShH any friggin machinist knows that for boring, you LOCK everything down.
12:04 GuShH the locks are there for a reason...
12:04 GuShH it's all about the operator, not just the machine.
12:04 GuShH give that guy a massive bridgeport and an engine block, he will ruin the block.
12:04 GuShH then blame it on the machine.
12:06 GuShH "it must make you feel real special that a prestigious gold poster that loves to boast about his vast knowledge and mastery on the worlds greatest machines is skeptical about what a hobbyist might do and report on a hobbyist blog seems to side with your overwhelming mastery of the same machinery. maybe both of you should start your own forum and call it we know more than you all. " haha
12:06 GuShH (cnczone.com)
12:08 GuShH discussion and offtopics are common human nature.
12:08 GuShH we like to argue and measure sausage.
12:19 GuShH rue_shop3: rough cut on left, polished fine cut on the right http://gushh.net/tmp/dscn5534f.jpg it's an M16 I turned down for a project, not wanting to use regular mild steel. it's going to be a straight arbor for a cheapie chuck, threaded on one end. So, cobalt tooling for interrupted cuts, thumbs up. I thought it would be more brittle, but it took a pounding just fine.
12:19 GuShH and that was a grade 8
12:20 GuShH HSS eventually chips under those conditions, with those coarse threads.
12:21 GuShH between centers you can take the coarse threads in two passes without much effort
12:21 GuShH I tried one pass, it was cutting it but sounded angry.
12:22 GuShH lowest feed is not low enough
12:26 robotustra a barrel?
13:24 GuShH robotustra: what barrel? arbor, shank
13:24 GuShH straight arbors are used on collets or sometimes chucked on a bigger chuck where precision doesn't matter
13:24 GuShH well, also toolholders
13:25 GuShH I really want to build a drilling jig for the lathe one of these days
13:25 GuShH similar to a toolpost grinder, but for drilling.
13:26 GuShH robotustra: since collets usually have at least 1mm range, the polished surface doesn't have to be perfectly on a specific size, but it's nice to aim for it at least.
13:26 GuShH 1 to 2mm isn't uncommon
13:27 GuShH I'm not sure if precision is lost the closer you get to it's absolute maximum closed position, shouldn't?
13:27 GuShH it should close uniformly
13:27 ShH ponders turning his first jacobs t
15:33 Tom_itx GuShH, wouldn't that be a GuShH taper?
17:04 GuShH Tom_itx: well, a jacobs inspired taper.
17:06 MrCurious what is all this talk of tapping gush
17:10 ShH h
22:29 GuShH yey first machine taper! alas on aluminum..
22:29 GuShH really sucks to feed using the compound
22:50 X-Scale http://www.ted.com/talks/raffaello_d_andrea_the_astounding_athletic_power_of_quadcopters
22:57 GuShH holy crap... with just the machined surface (using a scraping tool for the last pass) I got pretty good fit on the taper
22:57 GuShH I wonder if a quick polish would make it better
23:01 GuShH http://gushh.net/tmp/dscn5555f.jpg ... since the stock is hollow I didn't want to push the taper in (I wouldn't have a way to remove it) but... I'm happy with the fit just from pushing it in and out
23:02 GuShH hard to tell from the picture, but at least 50% coverage which is better than I thought it would be from just machining it, no extra finishing.
23:02 ShH throws a jacobs taper at Tom
23:03 GuShH it was in there good just from sliding it in.
23:03 GuShH I'd like to try a morse taper next, but it would have to be machined in steps...
23:03 Tom_itx a stepped taper?
23:04 Tom_itx hmm
23:04 GuShH the compound doesn't have enough travel
23:04 GuShH JT1 is short enough to machine it on a single pass with this lathe, but nothing longer than that.
23:05 GuShH I'd like to make a taper attachment one day though
23:05 ShH likes the finish the 'scraper' type tooling g
23:05 GuShH it's like a skew with a big contact area on the work