#robotics Logs

May 29 2015

04:09 akaziel Good morning
04:09 deshipu hi akaziel
04:12 akaziel Eh, i see it's quiet on every channel at this time of the day ^^
04:13 deshipu well, USA is asleep, EU is at work
04:14 deshipu Asia and Australia are not very talkative
04:15 akaziel makes sense
04:18 akaziel Does anybody know a good library/algorithm to measure speed with a 10.525GHz doppler sensor?
04:41 akaziel I guess not :p
04:44 deshipu tough luck
04:48 akaziel Eh
07:07 SpeedEvil akaziel: what is the output
07:10 akaziel https://www.parallax.com/sites/default/files/downloads/32213-X-BandMotionDetector-v1.1_0.pdf
07:10 akaziel So
07:10 akaziel 3.9V/0V square signal
07:10 akaziel 4% duty cycle
07:12 akaziel I get really low values
07:46 akaziel maybe I could use pulseIn(), properly...
08:25 deshipu rue_house: hey, you said once that you had a way to measure if a servo is loaded with its ADC pin?
08:25 deshipu s/its/an
08:38 SpeedEvil you can measure the input current
08:38 SpeedEvil In principel
08:53 rue_bed you dont need an adc pin
08:53 rue_bed you measure the time is pulls more than is idle current
08:53 rue_bed the longer it pulls current, the more error its correcting
08:53 deshipu right, how do I measure the current then?
08:54 rue_bed you can do it with a transistor and resistor
08:54 rue_bed I shoudl do a setup so I can show values
08:58 deshipu I kinda got compliant motion using an adc pin connected to the pot's middle pin
08:58 deshipu but it requires callibrating
09:03 SpeedEvil There are also fancy servos
09:03 SpeedEvil with position output
09:03 SpeedEvil but they are expensiv
09:04 deshipu yeah
09:04 deshipu I could also put an encoder on them
09:05 deshipu or a separate pot
09:06 deshipu but I want to keep things as simple as possible
09:10 rue_house the pot will only tell you the servos position, not its force
09:11 rue_house do you want to know real position, or force?
09:17 rue_house http://ruemohr.org/~ircjunk/tutorials/elex/hobbyservo/servo101.html
09:18 rue_house iirc the servo pulls about 120mA normally and jumps up to 500mA when the motor is active
09:19 rue_house do you can use a digital detector at about 200mA to track the motor pulse
09:21 deshipu rue_house: I want to know the load and direction, preferably
09:21 deshipu rue_house: but if I know the current position and the position I set, I can deduce the force and direction from the difference
09:22 deshipu ideally, I want to be able to tell if a servo is supporting the robot or hanging in the air
09:22 rue_house not really, it might have just not caught up yet
09:22 deshipu right
09:23 rue_house sounds like you want force then
09:23 deshipu assuming I gave it enough time to catch up
09:23 rue_house my method is probably too hard for ya to do
09:23 rue_house it involves measuring pulse times and stuff
09:24 deshipu I will probably just end up with switches at the ends of the feet
09:24 rue_house besides, if you dont do it, I can still be the first to.
09:24 rue_house and I want to be the first person to do this
09:25 deshipu well then, what are you waiting for? :)
09:25 rue_house I'm putting togethor a robot show for a local fair
09:25 rue_house did you see the video of the arms?
09:25 deshipu yeah, I did
09:26 rue_house hahah TODAY my browser isn't supported by youtube, AGAIN
09:26 rue_house they rolled back for a while
09:27 rue_house I got a program where I can save points and play them back
09:27 rue_house I'd like to set up that force feedback for the grippers on those arms
09:28 rue_house one day
09:50 deshipu hmm, I'm sure I had some mandoline strings somewhere
09:50 deshipu they would make nice whiskers
10:06 deshipu hmm, I wonder if I could solder a wire to the motor directly
10:06 deshipu to just see which way it is turning
10:18 deshipu that actually works much better!
10:30 veverak deshipu: switches sounds nice too though
10:35 deshipu veverak: it's too light for that
10:35 deshipu rue_house: just checking the voltage going to the motor is perfect!
10:35 deshipu rue_house: I get the force and the direction
10:57 Fuqr this seems to be the closest channel i can find to control engineering
11:00 deshipu OBEY
11:01 Fuqr or startup cult, whatevs
11:27 gundamlh hi
11:41 LiohAu rue_bed and rue_house are you the same person?
11:47 deshipu LiohAu: he actually transforms
11:47 deshipu LiohAu: like The Incredible Hulk
11:48 deshipu great success: https://www.youtube.com/watch?v=Ms8yTKYebaI
12:12 LiohAu deshipu: ok :d
14:57 sherrardtr4129 hello
19:32 rue_house all us rue_ are one
19:35 Triffid_Hunter rue_house: I use a znc bouncer and log into it from everywhere :P
19:35 rue_house I dont :)
19:36 rue_house hmm
19:36 Tom_itx rue likes to clone himself
19:44 _moon rue
19:56 Elleo 35
19:56 Elleo oops
20:21 _moon who can walk on thier hands?
20:24 Jak_o_Shadows nope
20:25 _moon :(
20:47 rue_house the nothing thats not holding the outdoor light to my house is now nolonger holding on the siding
20:48 rue_house thanks to a bear that decided to do some modern art with a jug of sunflower oil that was on the deck (last night, not as of this morning)