#robotics Logs

Aug 10 2013

11:18 rue_more I wonder if it'll drop hard right a thte last few volts
12:48 CrazyThinker Hi
12:48 CrazyThinker Is there any other mechanism to make a robotic arms without using servos?
12:48 CrazyThinker or stepper motor?
13:46 rue_shop2 how about pneumatics?
13:46 rue_shop2 why dont you want ot use servos?
15:07 GuShH rue_more: gears look brand new, needs a new 6000Z bearing that's all.
15:08 GuShH been using it all day long, I should fix it soon though otherwise the bushing will need to be replaced as well
15:08 GuShH no leak from the oil, great idea
15:41 rue_more yea, I was sure it was a silly idea, have gear oil pouring out eveywhere
15:41 rue_more just another win for an old fart
15:41 rue_more at this rate, in another year, I'll be screwing jam jar lids to the undersides of shelvs
15:42 RifRaf lol, since when did you get old fart status?
15:43 rue_more not me, the guy who aid to stuff gear oil in the angle grinder
15:43 RifRaf ah
15:43 rue_more the 20 hr discharge curve on this battery is taking a fine shape
15:44 RifRaf these reprints are a nice shape too
15:44 RifRaf had to redo every part
15:45 rue_more I have a landfull trip to do
15:46 rue_more 5 hours left on the battery test
15:46 rue_more it plate resistance might be off, but I think its capacity is still atleast 7.2Ah
15:53 RifRaf bit small to power a truck no?
16:15 rue_more I'v got some 4.9Ah li-ion I'm gonna evaluate for the truck
16:25 RifRaf for the interior light?
18:02 yahweh Hey, Rue
18:02 yahweh I'm coming over
18:07 MrCurious is that a threat?
21:24 MrCurious oh beagle... why you tempt me so... http://www.newark.com/jsp/search/productdetail.jsp?sku=65W6016&COM=embedded-link_DevKitsLearningCenter
21:24 MrCurious average rating 5 out of 5. there are no ratings other than 5
21:27 Tom_itx you should get one then
21:27 Tom_itx or two even
21:27 MrCurious i know riht
21:28 MrCurious but that would make all my other arm boards jealous
21:28 Tom_itx what makes it better than the others?
21:29 MrCurious $45, 1ghz, lots of io
21:31 Tom_itx linux support
21:31 Tom_itx reprap support with linuxcnc
21:33 Tom_itx what would you do with it?
21:34 MrCurious i would put it on my arm board shelf just to piss off GuShH
21:37 Tom_itx does reprap have a motor board for it yet?
21:37 MrCurious probably
21:37 MrCurious would you like me to google it for you
21:37 Tom_itx of course
21:37 MrCurious 1 sec
21:38 Tom_itx read it to me too
21:39 MrCurious http://circuitco.com/support/index.php?title=BeBoPr_Cape
21:39 MrCurious i am almost done chewing masters steak. is master ready for me to spit it in his mouth?
21:42 Tom_itx i saw one of those running linuxcnc on a mendlemax
21:42 MrCurious guess the answer was satisfactory then
21:42 Tom_itx i suppose
21:44 Tom_itx does the bbb have SD support?
21:44 Tom_itx ie a slot for one
21:45 MrCurious uSD i believe
21:45 MrCurious also has 2g of on board emmc
21:48 Curious meditates on doing software PWM with tim
21:48 MrCurious got a timer ISR going off 11x/sec
21:48 MrCurious 100x
21:48 Tom_itx avr?
21:48 Tom_itx or bbb
21:49 Tom_itx arm
21:49 MrCurious avr
21:49 Tom_itx i got an arm board but it's sitting in the drawer
21:50 MrCurious which one
21:50 Tom_itx stm32f4
21:51 MrCurious i gave one of those away
21:51 MrCurious not super hacker friendly with the pin arangement
21:51 Tom_itx yeah
23:02 rue_more ok, at 630mA the battery lasted 62000 seconds
23:02 rue_more how many Ah is that
23:04 rue_more .05C
23:05 rue_more 17.2hrs
23:05 rue_more and it should have lasted 20
23:05 rue_more 86%
23:06 rue_more my tester said 80%, but its graduations at 10%
23:06 rue_more so I'm guressing 6.2Ah
23:07 rue_more ok, so
23:07 rue_more if I dont know C
23:08 rue_more I'd be looking for what current would make it take 20 hrs to discharge
23:08 rue_more if I know at 630mA it took 17.2 hrs, then maybe I can try scaling
23:09 rue_more 542mA should take 20 hrs
23:10 rue_more 20*542 is 10.8Ah
23:10 rue_more thats not right
23:25 rue_more ok, cool, a few directions I get 6.2Ah
23:30 rue_more but I find it interesting that they show the voltage level till it dies
23:30 rue_more this batterys votlage gradually dropped off till it died
23:31 rue_more http://www.rctoys.com/pr/pr-images/tp-extreme-5000-discharge-curve-graph.gif
23:31 rue_more ok, manufacturers chart is garbage
23:36 R0b0t1 lol, the charts are always garbage
23:36 rue_more http://www.batteryweb.com/manuals/techman.pdf
23:36 R0b0t1 (I swear they get two data points and make the middle up)
23:36 rue_more this is a good doc
23:37 Jak_o_Shadows How many batteries are you looking at for your truck? What capacity
23:38 rue_more it looks like I'm going to 12kwh
23:38 Jak_o_Shadows Nice. What distance and recharge time are you hoping to get?
23:38 rue_more if the vacuum cleaner motors work out, 90V array
23:38 rue_more iirc distance is like 80km
23:38 rue_more dont care about recharge time
23:39 Jak_o_Shadows ha
23:39 rue_more 135km/h abs top speed
23:39 Jak_o_Shadows No need for any faster
23:39 Jak_o_Shadows Acceleration is going to be ok?
23:39 rue_more 100km/he is fine real limit, max limit here is 80km/hr anyhow
23:39 rue_more 200hp
23:39 rue_more er
23:39 rue_more sorry
23:40 rue_more 80hp, 200 foot/lbs
23:40 rue_more ish
23:40 rue_more 5000rpm
23:41 rue_more I need another version of 'figure 3' with finer grain on the 0-5Ah range
23:43 Jak_o_Shadows 80km/h is pretty low lol
23:43 rue_more http://files.qrz.com/w/wx3w/MVC-009F.JPG
23:43 rue_more hes gonna be pissed when the batteries on one end all fail
23:43 rue_more you cant get up to 80 either, too many tourists doing 40
23:44 Jak_o_Shadows Fail to short
23:44 rue_more even small differences int eh bresistances between the parallel batteries will drastically change the fail times