#robotics Logs

Mar 05 2014

00:08 rue_shop3 GargantuaSauce, gonna take with me and make servos now?
00:09 e_shop3 tries to draw GargantuaSauce to the dark
00:09 GargantuaSauce if and when i do, they'll be uniform and not a hodge podge of scrounged crap
00:10 GargantuaSauce when i scale up the hexapod i might not strictly use servos
00:10 GargantuaSauce something compliant might be a better idea
00:10 rue_shop3 woos
00:11 rue_shop3 software compenstion is needed anyhow
00:11 GargantuaSauce i know
00:12 GargantuaSauce tbh my Big Overarching Idea is to develop software that can fully learn and characterize and model its hardware platform with minimal a priori knowledge
00:14 GargantuaSauce but i am not going to use that an excuse for building egregious variability into the actuators
00:17 GargantuaSauce air muscles or double-acting pneumatic cylinders would be a pretty interesting approach
00:17 GargantuaSauce or perhaps fancy direct-drive motors i build myself
00:17 GargantuaSauce or series elastic actuators
00:35 rue_shop3 ok
00:35 rue_shop3 I'v gone thru almost all the PNP bipolars Ihave
00:35 rue_shop3 I'v done lots of datasheet digging and calculations
00:35 rue_shop3 my conclusion is to not use a pnp bipolar
00:36 rue_shop3 I conclude its possable to get less loss with an NPN bipolar operating in a 2V overhead of the converter
00:36 rue_shop3 tommorow I will search all my npns
00:36 rue_shop3 tho I have to draw that one
09:33 rue_mohr2 the battery packs came in for my 4-20 ma loop tool, I need to finish building it
19:49 rue_mohr2 ok
19:49 rue_mohr2 I been crunching numbers during all the job waiting I been doing today
19:50 rue_mohr2 I wont use an npn
19:50 rue_mohr2 instead, I'll use a N channel fet, and I'll make the dropout in the regulator used to charge a boost cap for the fet driver
19:51 rue_mohr2 33V in, 30V out, with losses give it 95% max duty
19:52 rue_mohr2 now to try and design the driver
20:00 GuShH_ rue_mohr2: I guess even cheap eye protection is better than none http://gushh.net/tmp/p_20140305_212313.jpg
20:00 GuShH_ a chunk of rust hit the left side at high speed.
20:01 GargantuaSauce ya that would've ruined your day
20:01 rue_mohr2 what were you diing??
20:02 GuShH_ power washing a motorcycle car trailer using a 0� nozzle.
20:02 GuShH_ prior to sanding and painting
20:03 GuShH_ rust would fly away, except for one big chunk, it hit a sharp corner and went right back at me :( stupid rust.
20:03 GuShH_ GargantuaSauce: I've had an incident with my right eye not long ago, but I wasn't doing anything other than staring up on a tree, a branch fell right into my right eye. I wasn't wearing protection...
20:04 GuShH_ Why would I, in theory you are just "walking on the park" what could possibly go wrong
20:04 GuShH_ Anyway, safety first!
20:10 orlock GuShH_: dude, remember to turn off the heat vision
20:10 GuShH_ lawl
20:13 GuShH_ yey... got a gasket and diaphragm kit for the walbro chainsaw carb, time to rebuild it!
20:13 GuShH_ one of the reed valves is bent slightly upwards, the diaphragm looks tired
20:18 orlock Why not just ANGLE GRINDER!
20:34 GuShH_ orlock: for what?
20:34 GuShH_ a 3 bike trailer? no thanks sir.
20:34 GuShH_ I would sand blast it, but I don't have the means for such big parts
20:35 GuShH_ so power wash and orbital sander it is, plus I'm not looking for a brand new finish, just looking to protect the steel, it's been over 10 years since it was last painted.
20:43 Triffid_Hunter just for fun I whipped up http://triffid-hunter.no-ip.info/astar/ to play with A* pathfinding algorithm :)
20:44 orlock oh, nice
20:44 orlock Hows the 3d printering going?
20:44 Triffid_Hunter nowhere to set them up here unfortunately
20:45 orlock I meant the business - still selling bits?
20:46 rue_mohr2 <rue_mohr2> the battery packs came in for my 4-20 ma loop tool, I need to finish building it
20:46 orlock loop tool?
20:47 rue_mohr2 for measuring or setting 4-20ma loops
20:47 orlock milliamp loops?
20:47 rue_mohr2 uh
20:47 rue_mohr2 industry uses 4-20ma current circuits for conveying sensor and control data
20:48 rue_mohr2 cause it negates resistance effects
20:48 rue_mohr2 you can power with the first 4ma
21:04 Houshalter Hello.
21:06 Houshalter I have a project I am considering and don't even know where to begin.
21:07 Houshalter I want to make a robot (or something) go around and sample hundreds of test tubes, do an automated test on them, and possibly dump them and refill them.
21:08 rue_mohr2 wait here for some answers
21:08 rue_mohr2 atleast a half hour
21:08 Houshalter ok
21:14 rue_mohr2 so you want an xy plannar robot?
21:14 Houshalter what does that mean?
21:15 rue_mohr2 sorta like a cnc router, can work over a plane area
21:15 Houshalter it will be a fixed environment
21:16 Houshalter i have no plans on how to organize it but something like that sounds good
21:16 rue_mohr2 well make a drawing of a thought, post it, show us, and we can make suggestions
21:17 Houshalter ok, just a sec
21:17 rue_mohr2 I'll start you with 3600 seconds
21:17 rue_mohr2 if thats not enough dont fret, I'm generous
21:17 Houshalter that sounds sufficient
21:21 Houshalter hmm well there isn't much to draw. I just want to have test tubes stored in some arrangement, and then automatically sample and replace them.
21:26 orlock Houshalter: Somebody else has been in here asking about similar stuff
21:29 orlock Houshalter: you could maybe use one of the 3d printer robots, actuator instead of extruder
22:15 Houshalter i don't have any experience with robotics. Where would I even start on a project like this?
22:16 orlock Houshalter: watch some viseos of 3d printers
22:17 orlock Houshalter: do you understand what rue meant when he said XYZ ?
22:17 Houshalter ya
22:17 orlock Houshalter: is this for bio samples, or other chemicals, etc?
22:17 Houshalter bio
22:18 orlock Houshalter: One thing you also have to worry about is cross contamination
22:18 orlock Houshalter: my brother actually works at one of the market leaders in making those exact things
22:18 Houshalter that is sort of a concern
22:18 orlock Houshalter: he said every 6 months or so, the software QA guys go to the abbitour/butchers and get a few gallons of bigs blood
22:19 orlock pigs blood, for testing
22:19 orlock (or half a big, for the endoscope guys)
22:19 orlock s/big/pig
22:20 orlock Houshalter: anyway - i'd say, look at some of the mechanisms the 3d printers use to move the extruder around, and figure out what sort of working area you will need
22:20 orlock Houshalter: actually - i think some guy on LMR made something similar already, using one of the industry standard sample trays
22:20 orlock they are not test tubes, more trays with dimples?
22:26 Houshalter I don't know what I am going to use yet
22:26 Houshalter any kind of small liquid container
22:26 orlock ok, well there are several standards in the "industry"
22:27 orlock https://www.google.com.au/search?q=laboratory+sample+trays&source=lnms&tbm=isch&sa=X&ei=QPUXU8T_LcTCkwWYv4CQDQ&ved=0CAkQ_AUoAQ&biw=1265&bih=489
22:29 orlock Hmm, cant find one
22:29 Houshalter pretty much any of those are ideal for my purposes
22:29 orlock its what they are made for!
22:30 orlock now you need to make an actuator that opens/closes a syringe or similar
22:30 Houshalter but how expensive are they?
22:30 orlock the trays are likely to be dirt cheap
22:30 orlock http://www.marcmart.com/makeblock-xy-plotter-drawing-robot-kit-compatible-arduino-with-electronics-for-adults.html
22:33 orlock Houshalter: Uni i assume?
22:34 Houshalter i'm thinking something different so i can expand it or have vertical rows
22:34 orlock Houshalter: I know that you are intending on looking at this stuff for anything relating to human consumption, the FDA should be your first place to call
22:35 orlock Houshalter: Easy enough to expand - but i'd be worrying about your actuator, and sample cross contamination, etc
22:35 Houshalter no, it's my own private project surprisingly
22:36 orlock also, breast pumps
22:36 Houshalter breast pumps?
22:36 orlock may be usefull in some way
22:37 Houshalter thats not a bad idea
22:37 orlock or something like a servo/linear actuator hooked up to a syringe
22:37 orlock they can vary widely in price - i think i saw some cheap, but "name brand" consumer pumps for under $10
22:38 orlock the "industrial grade" ones are thousands
22:38 Houshalter my main concern is the robotic stuff. microcontrollers and servos and stuff. I don't know how to use them or where I would get them or what to get
22:38 orlock microcontrollers - you can get something that easy to experiment with called an arduino reasonably cheaply
22:39 orlock servos - ebay, or local hobby store
22:39 orlock also, look at printers - inkjets, etc. they have lots of bits for moving heads left and right, feeding paper, etc
22:40 Houshalter i have a few dead printers, will those motors work on DC?
22:40 orlock yeah, they are all DC internally
22:40 orlock but they need drivers
22:41 orlock there will be some in the printer
22:41 orlock got soldering iron?
22:41 Houshalter ya
22:43 Houshalter would it be difficult to connect the microcontroller to an external computer? Like have it do it's task and then come up and "dock" with it somehow, feed it it's data and wait for instructions.
22:45 orlock trivial, depending on what you want to do - you would generally have it connected via USB all the time
22:45 orlock go and get an arduino starter kit
22:47 Houshalter that might work, I just didn't want it to have to be permanently anchored to a usb, but it might not matter
22:48 orlock Houshalter: they dont have anything much in the way of usable long term storage
22:48 orlock so any data to keep either will go out via serial over USB, or get written to a card
22:48 Houshalter ah that sucks
22:49 orlock nah, nature of what they are
22:49 Houshalter it doesn't matter if I use an external computer though
22:49 orlock Which state/country are you in?
22:49 Houshalter ohio, US
22:50 orlock ok, you should have no problems finding stuff
22:51 orlock also, try a hackerspace
22:52 orlock you have almost 20 in the state
22:52 Houshalter how difficult would reading and writing to a card or something be
22:52 Houshalter I've never heard of it
22:53 orlock http://hackerspaces.org/wiki/Ohio
22:53 orlock Never had to do it, but not hard. google arduino
22:54 Houshalter im reading about them right now
22:55 rue_shop3 I'm gonna have to do math, design the inductor for this
22:56 rue_shop3 5A 40V switching inductor @ hmm 100khz or 300khz
22:56 rue_shop3 maybe 100k
23:13 Houshalter would I need analog outputs or digital ones?
23:47 TELunus Houshalter: If you don't want it constantly tethered by USB you could use wireless comunication. There's a simple one called XBee that can pretty easily be connected to an Arduino.
23:48 Houshalter that would be cool
23:49 orlock yeah, or bluetooth or whatever
23:49 Houshalter that sounds expensive though
23:49 orlock nah, bluetooth is cheaper than xbee
23:50 orlock xbee is relativly niche, bluetooth gear is everywhere - then you could store data directly on a phone
23:50 orlock go and look at letsmakerobots.com and hackaday.com