#robotics Logs

Oct 11 2015

00:55 rue_shop4 ?
01:13 rue_shop4 it was the 7824, apparently they need some input capacitance
03:19 deshipu why do people always want to start with huge robots?
06:08 ace4016 flashy
11:09 verak wanted small robot, because he wants to take it everywhere poss
15:09 niepoo wants a big robot that goes everywhere with me on own p
15:11 deshipu Anniepoo: I'll take two of those
15:12 deshipu Anniepoo: and large frites
15:12 Anniepoo 8cD
15:13 Anniepoo my partner has an excavator - backhoe type machine on treads
15:13 Anniepoo I would SOOO love to make it autonomous
15:15 Anniepoo I had a dream one night where for some reason they'd let Kevin enter it as a battlebot, but got pissed when he ran over the saws in the floor and smashed them
15:19 rue_house Anniepoo, seeing the price of hydraulic servovalves will shatter your dream
15:19 rue_house keep the dream alive!
15:20 Anniepoo not to mention thinking about designing a servo system to keep that thing from shaking like heck
15:20 rue_house servo valves are proportionate
15:20 Anniepoo PID controller probably won't cut it
15:21 rue_house I made a standard solinoid do position control just with PD
15:21 rue_house did you see it?
15:21 Anniepoo no
15:22 rue_house https://www.youtube.com/watch?v=4tG2bTOGxK0
15:22 rue_house it only got away when I pushed it too hard
15:22 Anniepoo is the fast shake controlled?
15:22 Anniepoo 8cD
15:23 rue_house no, its from the magnetics latching up
15:23 rue_house but its just a regular solinoid, on/off type
15:23 Anniepoo whats the encoder?
15:23 Anniepoo yup
15:23 rue_house its a strip encoder from an HP printer
15:24 Anniepoo first robot I ever made was pneumatic. Used a length of nichrome wire and a slider as encoder
15:24 Anniepoo worked surprisingly well
15:24 rue_house cool
15:24 rue_house what did you use as a brush?
15:24 Anniepoo piece of beryllium copper
15:26 rue_house so it was a lienar machine?
15:26 rue_house cylinders?
15:26 Anniepoo I'm kind of surprised the whole thing worked as well as it did. 4 washing machine style valves, PVC pipe & leather gasketed piston,
15:26 rue_house oh good show
15:26 Anniepoo compression fitting drilled out, with o rings in it as a packing
15:27 rue_house so, now shall I show you how to do proportionate control of a washing machine valve?
15:27 Anniepoo about 4 ft long
15:27 Anniepoo sure
15:27 rue_house you pulse them
15:27 Anniepoo yes
15:27 rue_house there is a pulse time range that they are almost linear
15:27 rue_house https://www.youtube.com/watch?v=fq1uXv_NfrQ&list=PLEAC147CDF6E03FEA
15:28 rue_house appologies for the audio
15:28 Anniepoo I worked on a Burroughs B800 computer that had a coffee can sized permag solenoid to move the disk heads
15:28 rue_house oh they play to the end of the audio now, skip it
15:29 rue_house https://www.youtube.com/watch?v=A-WgzH-UZgM&index=2&list=PLEAC147CDF6E03FEA
15:29 rue_house that one you can hear the pulsing
15:29 Anniepoo you said before you used a balloon?
15:29 Anniepoo what's the air pressure?
15:29 rue_house https://www.youtube.com/watch?v=_JPpA1llSm4&index=3&list=PLEAC147CDF6E03FEA
15:29 rue_house thats exhaust pulsing
15:29 Anniepoo also, how far away is the valve?
15:29 rue_house thats an air mulcle
15:29 Anniepoo yes
15:30 rue_house its right there, my appologies for now zooming out
15:30 Anniepoo did you make it, if sowhat's the air bladder? a balloon?
15:30 rue_house https://www.youtube.com/watch?v=s7rxZD09rcc&list=PLEAC147CDF6E03FEA&index=4
15:30 rue_house yes, its a balooon
15:30 rue_house there you can see the setup
15:30 rue_house thats non-servo
15:30 rue_house then I servod it
15:30 rue_house https://www.youtube.com/watch?v=z2xWgEdiTwc&list=PLEAC147CDF6E03FEA&index=5
15:30 rue_house in that one, and described the setup
15:31 Anniepoo and why are you wearing welding gloves?
15:31 rue_house so you can tell if I'm an alien masquerading as a native
15:32 SpeedEvil https://www.youtube.com/watch?v=zMQjcukphpA - in case you need a 300kW drive.
15:33 Anniepoo oh, don't you have the 'look like a native' transforming app?
15:33 rue_house too much work
15:34 niepoo has a 50ma 50KV supply in next room
15:34 Anniepoo =8cO don't want to get caught across that puppy!
15:37 deshipu Anniepoo: would a swarm of small robots following you not suffice?
15:37 deshipu Anniepoo: or a small robot riding on your arm?
15:37 Anniepoo sitting in lap 8cD
15:38 Anniepoo hey, that was KW, I read W!!!
15:46 deshipu it would be interesting to come up with a body navigation algorithm
15:46 deshipu so the robot would know where on your body it is
15:46 deshipu and how to get to other places
15:47 Anniepoo be hard - it's got to navigate in a shifting accelerating field
15:47 deshipu also, it would move around depending on your posture
15:47 Anniepoo of course you too would move around depending on where it was
15:47 deshipu when you stand up, sit on your arm, when you sti down, move to your lap, etc.
15:47 Anniepoo so there would be feedback loops
15:48 Anniepoo aaah... aaah... get it off me!!!
15:48 deshipu when you lie down, sit on your chest and start strangling...
15:48 Anniepoo like a steel kitten
15:49 deshipu but mostly just hold onto you
15:49 niepoo is here, with a robot tangled in her
15:50 deshipu if it was small enough, it wouldn't tange
15:50 deshipu tangle
15:50 Anniepoo yes, then it'd be more like having spiders crawling on you
15:50 Anniepoo =8cO
15:51 Anniepoo I think you have some RHI problems to work out with that!
15:51 deshipu I don't mind spiders
15:52 deshipu now I'm thinking about a special shirt
15:52 deshipu that would have holding points for the robot
15:52 deshipu and maybe some sensors and/or markings for it to read
15:52 Anniepoo of course the shirt moves on your body
15:52 deshipu sure
15:52 Anniepoo that's the problem with data gloves
15:53 deshipu it wouldn't be accurate
15:53 deshipu but better than nothing
15:53 Anniepoo well, it's accurate for the shirt - and it's the shirt it's holding onto
15:53 deshipu the holding points could have beacons in them
15:54 Anniepoo so it can know 'I'm over hold point 17, hold point 18 is 2 " thatway
15:54 deshipu right
15:54 Anniepoo shirt could be loop side of velcro, robot could have hooks
15:54 deshipu hmm, velcro you say...
15:54 deshipu probably not strong enough for a running person
15:55 niepoo is here, wondering if this velcro top makes her look
15:55 Anniepoo also, you could cover a wall with hook side material and have a lot of fun
15:55 deshipu more like some rings that you could lock on
15:56 Anniepoo velcro can be quite strong
15:56 deshipu so that the robot could hold on onto you while you do rapid movements, and move around when you are still
15:56 Anniepoo dunno, I don't think I'd like a thing moving around on me
15:57 deshipu how about a shirt with some displays on it, having this "moving" creature
15:57 deshipu so it would be more virtual
15:57 deshipu much easier for the start
15:57 deshipu but would still move around based on your posture
15:57 Anniepoo that makes more sense from RHI standpoint, yes
15:58 deshipu a display shirt crawling with spiders, that would congregate towards places where something touches you :D
15:58 deshipu great for ahlloween
15:59 Anniepoo and treating arachnophobia by the exposure method
16:00 Anniepoo also great for behavioral approaches to schizophrenia
16:01 deshipu why?
16:02 Anniepoo I'm joking - such a shirt would be the LAST thing you'd want to expose them to, I'd guess - being covered in spiders is a common hallucination
16:03 deshipu well, it's one thing our nervous system has hardcoded
16:03 deshipu but it's more a touch sensation, not visual, no?
16:03 Anniepoo a more approachable way to have a virtual robot that 'moves' over environment would be a projector and a gnomen
16:04 Anniepoo if you could project an image anywhere on any surface in the room you could do some interesting things
16:05 Anniepoo like have it remember and point out where you kept the baking soda
16:05 Snert sounds like clockwork orange where they re-programmed that guy.
16:05 Anniepoo a shirt with display would be great for clubbing
16:06 niepoo starts thinking how to weave display c
16:06 Snert how about a dog coller?
16:07 Anniepoo depends on the kind of club =8cO
16:07 Snert not enough utility for the display prolly, on a dog.
16:08 Snert wearable pet stuff I mean.
16:08 Anniepoo business idea - take one of those vest things like seeing eye dogs have
16:09 Anniepoo mount advert on either side
16:09 Anniepoo run lots of dogs through neighborhood
16:09 Snert your seeing eye dog makes bank? lol
16:09 Anniepoo =8cO
16:09 Anniepoo somebody did na art project in SF
16:10 Anniepoo put LED signs atop taxis, and had a website, you could type stuff in and it appeared on the taxis
16:11 Snert a medical vest?
16:11 deshipu get a lot of cars, put a bright RGB led and a localizer on each, crowd them in one place, and display stuff with them
16:11 deshipu s/cars/cats
16:11 deshipu I can't type
16:11 deshipu guinea pigs would work too
16:12 Anniepoo LOL
16:14 deshipu hmm, that projector thing, it doesn't have to be that complex
16:14 deshipu just a bunch of laser leds and two servos
16:14 deshipu you could have a pet space invader
16:15 deshipu or you could use one of those car projectors, the ones that display the manfufacturer's logo on the sidewalk when you open the door
16:15 Anniepoo back in 70's/80's concerts often had a 'laser show' - visual laser steered by galvenometers with morros
16:16 deshipu the thing is, you are displaying the same thing all the time
16:16 deshipu you don't need to have pixels in there
16:16 Snert thems was the days. Pink FLoyd :)
16:16 Anniepoo people eventually realised, on an overcast day you could write on clouds
16:16 Anniepoo 8cD
16:18 deshipu so, are there electrosensitive paints?
16:19 Anniepoo as in paints that darken on application of current?
16:19 deshipu http://www.madsci.org/posts/archives/1998-10/905478465.Ch.r.html
16:20 Anniepoo there should be. I used to have a telex machine, it uses electrosensitive paper - it was purple, you had to use an iron stylus, so probably a reaction with it
16:20 deshipu but that's permanent
16:20 Anniepoo yes
16:21 deshipu I suppose the easiest way is to use uv paint and have some uv diodes in there
16:21 SpeedEvil deshipu: bats
16:22 deshipu SpeedEvil: baseball bats?
16:22 SpeedEvil not cats
16:22 deshipu SpeedEvil: drunk ducks
16:41 veverak rules[i] = dict(zip(range(1, alphabet_n+1),[int(n) for n in next(s).split(' ')]))
16:41 veverak this is so evil!
16:41 veverak I love it
16:41 veverak :)
16:43 deshipu meh
16:43 deshipu seen worse
16:44 deshipu ok, transparent uv-glow paint and uv LEDs ordered
16:45 deshipu will see how that works out
16:51 veverak glowing tote?
16:51 veverak P.S: update
16:51 veverak rules[i] = dict(zip(string.ascii_lowercase[:alphabet_n],[int(n) for n in next(s).split(' ')]))
16:51 veverak I love school projects :)
17:30 veverak deshipu: have you thought about different way of running "annimations" ?
17:30 veverak or running the moves?
17:30 verak thinks that actuals totes way is good, but is curious about alternat
17:31 veverak I mean, if I know only one way ho to solve problem... I want to know more ways :)
17:31 deshipu veverak: yeah, but I can't be bothered to program it all
17:31 deshipu veverak: there is a million ways
17:32 deshipu veverak: I'd love to have different motion tweens
17:32 deshipu also, to plan the leg movement better than just "get all the servos in position as fast as possible"
17:33 deshipu for instance, make all the servos reach the destination at the same time
17:33 veverak that would overflow i2c I am afraid :)
17:33 veverak deshipu: what way?
17:33 veverak speak :D
17:33 deshipu not really, the servos are 50Hz anyways
17:33 deshipu plus, you can have the motion controll on the avr
17:34 deshipu and only send the destination over i2c
17:34 veverak yeah
17:34 veverak nah
17:35 veverak have to get proper idea about how much can i2c handle
17:37 deshipu https://hackaday.io/project/6748-127-towerpro-servos-one-i2c-interface
17:37 deshipu btw
17:38 veverak P.S: I would not definetly sync
17:38 veverak more like get general idea
17:38 veverak servo.set_angle(angle, time)
17:39 veverak where time is after what time it should get there
17:39 veverak deshipu: that looks awesome
17:40 deshipu i2c is 10kbits/s in the low-speed mode
17:41 deshipu you need 12 * 16 * 50 = 9600 bits/s to control the 12 servos at 50Hz
17:42 deshipu hmm, that's actually too close
17:42 deshipu fortunately you don't need to send a new position every frame
17:43 shipu -->
17:43 veverak good
21:52 rue_shop4 what?
21:53 rue_shop4 12 servos...
21:53 rue_shop4 oh, maybe
21:53 rue_shop4 but if your running more than 8, your gonna collide timer interrupts and have unstable timing
22:26 RobotDuty Last night, we discussed axle, shaft and gear. I didn't understand it. Today, I do and I wonder a thing : where can we buy cheap and solid equipment around the axle, like gears, pulleys, elastics and so on?
22:28 RobotDuty Most importantly : How can I be sure I the have the right gear set to the axle. Do I need to draw everything in software like Autodesk Inventor before or I can use other simple tools online?
22:34 rue_shop4 RobotDuty, missed it, waht are you making?
22:41 RobotDuty rue_shop4, a robot (weight less than 300 lbs) (30 x 30 x 30 cm³) with a drill (permagnent magnet motor) and 4 wheels (two wheels for stability) and 2 wheels for movement.
22:43 RobotDuty according to my calculation, the maximum possible weight I can add (suppose I put lead on) will be around 90 kg.
22:44 RobotDuty For now, I'm thinking about the design for the wheel, motor and axle solder to the base frame of my robot.
22:45 RobotDuty I wonder where I can buy cheap and solid axle with gear and pulley.
22:51 RobotDuty (I will be back in 1-2 hours, but you can comment if you have suggestions. Thanks :))
23:24 rue_shop4 ugh
23:24 rue_shop4 why so big?
23:24 rue_shop4 drill motors are kinda small
23:25 rue_shop4 dont solder structure it'll let go
23:25 rue_shop4 drill + bolt
23:53 psYbR hi guys. I'm having some real trouble locating matching sprockets/spurs and appropriate chain. Can someone point me in the right direction? (common chain types etc?)
23:53 psYbR cheers
23:53 psYbR bicycle size
23:56 rue_shop4 hmm
23:57 rue_shop4 I get scrap bikes from the dump