#robotics Logs

Dec 01 2019

12:46 AM rue_shop2: I think the serial keybaord that I already made would do a fine job of the tiny13 based water dispenser controller
12:51 AM rue_shop2: I mean an i2c slave library is great and all, but I'm not sure I need to
02:54 AM Jak_o_Shadows: ah, dammit
02:54 AM Jak_o_Shadows: I didn't actually measure the part before I hit print
02:54 AM Jak_o_Shadows: of course it's too small - nothing was designed.
02:54 AM Jak_o_Shadows: the shape is good though, and it printed the overhangs ok
03:07 AM Jak_o_Shadows: Also, australians in the channel - where do you get your filament?
03:32 AM chisight: from crocodiles, where do you get yours mate? :-))
03:35 AM Jak_o_Shadows: Honestly, I got the last lot from Aldi
03:42 AM chisight: just kidding of course.
03:57 AM rue_bed2: ok
03:58 AM rue_bed2: so, do I work on the software i2c slave library I dont really need right now, or the code for the water dispencer I'm trying to get myself to actually build
04:03 AM Jak_o_Shadows: I mean, once you have the software i2c slave, you'll use it more
04:04 AM rue_bed2: yea, but I want to get my water dispencer done
04:04 AM rue_bed2: I did a serial keyboard, its only 2 lines
04:04 AM rue_bed2: clk, data
04:04 AM rue_bed2: and I have an i2c screen
04:05 AM rue_bed2: so, at worst thats 4 pins
04:05 AM rue_bed2: that gives me 1 pin for the solinoid
04:05 AM rue_bed2: which is all I need
04:05 AM rue_bed2: oh
04:06 AM rue_bed2: AND I did a 2 wire 74hc595
04:06 AM rue_bed2: so I dont even need to use the i2c screen I have
04:06 AM rue_bed2: it was so much easier when I was a beginner and there was only one way to do something
04:12 AM Miyu is now known as hackkitten
04:32 AM veverak: lol
04:46 AM rue_bed2: ok I found my program for fixed division and got the code to divide a number by 33.3333
12:37 PM Solifugus: In rough terms, how much weight could a 12 vdc motor pull?
12:37 PM Solifugus: Could it lift say 200 lbs at a reasonable speed?
12:38 PM Solifugus: I am trying to determine if a need 12 or 24 VDC for the legs of a full sized humanoid.
12:39 PM Solifugus: Then I will buy controllers and motors, accordingly..
12:40 PM Solifugus: Speed isn't super important becausse it will balance using a flywheel... however, not too turtle-like slow.. don't want to have to gear down too much.
12:40 PM Tom_L: 5 tons
12:40 PM Tom_L: if you gear it right
12:41 PM Solifugus: I presume 5 tons moving at about 1 rotation per month?
12:41 PM gartt: Yeah, all depends on gearing
12:41 PM Tom_L: you need at least one more parameter to that equasion
12:42 PM Solifugus: Right so.. if I want a leg to move at a typically human like pace.. I am not sure how many rpms that is.. maybe no slower than 1 rpm?
12:42 PM Solifugus: or 2rpm??
12:44 PM Solifugus: I just need a rough idea... I will experiment based on that.
12:47 PM Solifugus: OK.. Maybe I can just buy this and some of each 12VDC and 24VDC motors.. https://www.sparkfun.com/products/retired/9665
12:50 PM Solifugus: But I am not sure if the "feedback" is talks about is electrical resistance or just for position from 4-wire servos
12:51 PM Solifugus: I was hoping for electrical resistance to measure pressure applied.
12:54 PM gartt: If you're working on a full-sized humanoid robot, you're going to need a team of phds and hundreds of dollars in funding
12:54 PM Solifugus: No.. I really don't.. the money is no problem.. It's simple.. I am focused on softare.. just need help with electronics part..
12:57 PM gartt: hundreds of thousands of dollars*
12:57 PM rue_mohr: how big?
12:58 PM gartt: At least to make something that does anything cool in a full sized humanoid. Look at how many minds and the enormous funding behind ASIMO and how crappy it was in the beginning
12:58 PM gartt: And you had teams of very very smart people working on the software and hardware
12:59 PM gartt: And the circuit boards were blessed by priests before being installed
12:59 PM rue_mohr: gartt, priests dont detect crossed traces
01:00 PM gartt: Ok, I might have lied about the last part
01:01 PM rue_mohr: well, my 12' mecha is using pneumatic muscles, everyone should just do that
01:01 PM gartt: Why not hydraulic?
01:02 PM gartt: I thought pneumatics got too bouncy and imprecise in anything larger than small robotics
01:14 PM rue_mohr: if a hydraulic robot falls it breaks,
01:14 PM rue_mohr: pneuamatics just take up impact
01:15 PM rue_mohr: compliance
01:17 PM gartt: rue_mohr: Interesting. How about different performance in different temperatures?
01:17 PM rue_mohr: closed loop control
01:18 PM gartt: Doesn't it act funny under loads due to the elasticity?
01:18 PM rue_mohr: closed loop control
01:21 PM rue_mohr: are you familiar with a solenoid ?
01:23 PM rue_mohr: like for engaging clutches in printers?
01:42 PM gartt: rue_mohr: I wouldn't even remember my own name if it wasn't written on my underwear
01:43 PM gartt: But I know the basics
01:48 PM gartt: But I thought for larger robots, it was very difficult to take the springyness out of pneumatic actuators due to the gas compression under load. How would solenoids help that? By putting them at different points like a poor man's circulation cut-off?
01:53 PM rue_mohr: I'm just trying to help you understand closed loop control
01:55 PM Tom_L: rue_mohr, your toys coming from china?
01:55 PM Tom_L: so ~4 weeks out...
01:56 PM gartt: Right, but how could even closed loop control anticipate the springiness of a sudden load? For example, I give your mecha a heavy dumbbell and the pneumatic arm sinks a bit to do the weight compressing the gas before it lifts to maintain position
01:57 PM gartt: Then, I take the dumbbell from your mecha and its arm goes up before it adjusts to set it lower back to the position it should be at. With hydraulics, this is minimal or unnoticeable. That's all I meant by springyness
02:20 PM gartt: Then, after demonstrating springyness, I proceed to dance. Dance like I've never danced before. The room spins around me. The beat echoes through my chest. I feel really alive
02:22 PM gartt: The mecha tries to one-up me by trying to do the robot and falls, like ASIMO's bad spill when it missed a steps down a set of stairs
02:22 PM gartt: It may be 12' tall, but no match for the slippery wax of the dance floor
02:26 PM rue_mohr: you should play more with closed loop control
02:28 PM rue_mohr: https://www.youtube.com/watch?v=5iV_hB08Uns
02:28 PM rue_mohr: gartt, ^^ closed loop control
02:34 PM gartt: rue_mohr: Thanks
03:27 PM sinnded69157 is now known as sinned6915
11:58 PM sinned6915: rue_mohr: i am lusting for one of your solderservers
11:58 PM sinned6915: where can i find more info on it?