#robotics Logs

Mar 29 2015

02:18 rue_shop3 1.5:1
02:19 rue_shop3 1.500 = 06 : 09
02:19 rue_shop3 1.500 = 08 : 12
02:19 rue_shop3 1.500 = 10 : 15
02:19 rue_shop3 1.500 = 12 : 18
02:20 rue_shop3 want the main gear to be about 5.5cm
02:21 rue_shop3 so thats either the 9, 12, 15, or 18
02:22 rue_shop3 all too small
02:23 rue_shop3 my largest gear is only 38mm
02:23 rue_shop3 might have to scale
11:22 SquirrelCZECH guys
11:23 SquirrelCZECH is thre some project to control 2xpwm outputs attached to arduino with PC that is connected to that arduino?
11:23 SquirrelCZECH ideally keyboard
11:23 uirrelCZECH got RC Car here, that he want's to tes tbut it's too lazy to figure out somet
11:23 SquirrelCZECH P.S: RC without rc controller
11:45 deshipu SquirrelCZECH: my robots do that
11:45 deshipu except it's 12xpwm
11:45 SquirrelCZECH :D
11:46 SquirrelCZECH Firmata saved the day
13:06 rue_house I have one that controls 8
13:06 rue_house uses an atmega328
13:07 rue_house its raw C, but can be loaded onto an ardiuno just the same
13:08 rue_house SquirrelCZECH, ?
13:16 deshipu rue_house: there is one for atmega328 that controls 18: https://github.com/thebiguno/stubby/tree/master/avr/lib/pwm
13:18 deshipu hmm, why did they make the VL6180 take 2.8V :/
13:18 deshipu and not 3.3
14:06 rue_house mine is better
14:06 rue_house trust me
14:09 rue_house mine has about 11 bits of precision
14:09 rue_house and is completely stable
14:10 deshipu well, hexapods need 18 servos
14:10 rue_house if you put 18 of them on an avr, you will NOT get consistant control pulse timing
14:10 rue_house it WILL have glitches
14:11 rue_house glitches that will probably casue servo jitter
14:11 rue_house I wrote mine to have rock solid timing
14:12 rue_house its 1 or 2 cycles as close as you can get to perfect
14:13 rue_house it looks like this uses an 8 bit timer,
14:13 rue_house if so...
14:16 SquirrelCZECH guys
14:16 SquirrelCZECH Firmata was still perfect :D
14:16 SquirrelCZECH but just for testing
14:16 SquirrelCZECH for final stage I need something different
14:16 SquirrelCZECH question is: WHAT? :)
14:17 rue_house the range is from about 8 to 31 units, leaving 23 units of operability for the servo, so less than 5 bits precision
14:17 rue_house mine has 24000 units of operability
14:18 SquirrelCZECH A. it's going to be arduino
14:18 SquirrelCZECH because it's easy to obtain
14:18 rue_house so I'm over 14 bits
14:18 SquirrelCZECH B. I must have abillity to control 2 servos, but more can be better... I think that if I use full capabillity of Uno it's nice
14:18 rue_house the code I wrote uses an atmega328, the same one found on all the cheap arduino boards
14:19 rue_house you can load my code on there with arduino tools
14:19 SquirrelCZECH C. it should be able to talk on: USB, i2c, with RC controllers for first 2 channels
14:19 rue_house it controls 8 servos with over 14 bits of precision
14:19 SquirrelCZECH the last one need interrupts
14:19 SquirrelCZECH read PWM -> output PWM
14:19 rue_house it uses a 2 byte serial protocol, at 9600 baud
14:20 rue_house meaning your good for 480 updates/sec
14:20 SquirrelCZECH that's overkill :D
14:20 rue_house if you update every servo on every pass, thats 60hz per channel
14:20 rue_house which is the pwm update rate of the servo
14:21 rue_house (I used 60Hz update and not 50Hz)
14:21 rue_house by all means, please use an arduino library that promises to give you 8 bits and only provides 5 or 6 that jitter like hell instead
14:22 rue_house iirc, the range on arduino is 0-100 anyhow
14:24 rue_house I'm just bitter that nobody but me seems to have done it properly yet
14:24 rue_house its not hard
14:24 SquirrelCZECH :D
14:24 SquirrelCZECH it's open source world
14:24 SquirrelCZECH nobody does unles somebody really needs it
14:25 rue_house there is not ONE wav player library out there for arduino that works properly
14:25 rue_house NOT ONE
14:25 rue_house WTF!?!?!?
14:25 rue_house this is not hard people!
14:28 SquirrelCZECH :D
14:29 rue_house trying to use arduino libraries should not result in me teared up, bashing my head on the desk crying "WHY!?"
14:30 rue_house I dont have time to write every library ever
14:30 rue_house cant anyone write a library function that works properly?
14:31 rue_house there DO seem to be a few, dont get me wrong
14:33 SquirrelCZECH :D
14:33 SquirrelCZECH PID I once found seemed nice
14:34 rue_house pid can always be fun to get working
14:34 SquirrelCZECH yeah
14:34 rue_house what did you have it controlling?
14:34 SquirrelCZECH airship motors
14:34 SquirrelCZECH + gyro
14:34 Anniepoo 8cD be the revolution you wish to create 8cD
14:35 SquirrelCZECH so
14:35 SquirrelCZECH what I need:
14:35 SquirrelCZECH or, what is goal of my controller unit
14:35 SquirrelCZECH 6xPWM output, i2c controol, serial control, 6xPWM reading
14:37 SquirrelCZECH temperature control
14:38 SquirrelCZECH (when sensor is overheated, shut off PWM output)
14:39 rue_house well, work out your precisions
14:39 SquirrelCZECH hardly any significant I would say
14:39 rue_house 2 bit pwm control is easy
14:39 SquirrelCZECH I suppose that making it on one arduino would kill me
14:40 SquirrelCZECH but splitting the job into two arduinos would make simple solution
14:40 SquirrelCZECH board A: 6xPWM output, i2c, serial control, board B: 6xpwm reading, serial/i2c communication with A
14:41 rue_house the main() loop of my control code could watch an analog channel and do a shutdown
14:42 rue_house using the arduino i2c library will make life easy, but will take up must of the space on the controller
14:42 SquirrelCZECH I can imagine
14:42 SquirrelCZECH nah
14:42 rue_house "WHY!??!" thump, thump, thump...
14:42 SquirrelCZECH Arduino UNo can handle only 2x interrupt the easy way
14:42 SquirrelCZECH fuck this
14:43 uirrelCZECH doesn't need 6xPWM reading so
14:43 SquirrelCZECH either I will use the arduino controller by i2c/serial to control the robot/rover
14:43 SquirrelCZECH or I attach RC Receiver instead of the arduino
14:43 SquirrelCZECH DONE, next();
14:43 rue_house http://www.robot-electronics.co.uk/acatalog/I2C_Tutorial.html <-- when you decide to resort to bit-banging it, that seems to be a fine reference
14:45 SquirrelCZECH nice, thanks! :D
15:20 SquirrelCZECH I hate my brainstorming
15:20 SquirrelCZECH frew minutes thinking about what I could do
15:20 SquirrelCZECH "led battery intidactor", "follow line system", "better wheels", "automatic charging"
16:07 rue_shop3 ARG, WRONG PRINTER, THE DATASHEETS ARE COMMING OUT IN 3D!
16:08 SquirrelCZECH :D
16:09 niepoo . o O ( That particularly sucks with the plasma cutt
16:44 rue_shop3 why are my old audio caps half the ESR of the new "low esr" caps?
16:44 Tom_itx not made in china?
16:49 rue_shop3 were talking caps that are also about 15+ years old
16:50 rue_shop3 and they beat some that are less than 8
16:50 Tom_itx are you really surprised?
16:59 rue_shop3 yes, esp cause the "low esr" caps came off a motherboard that was fine
16:59 rue_shop3 they aren't bad caps, they all read the same
18:10 bindigoat https://indymedia.org.au/files/starship_0.pdf
18:33 armyofevilrobots rue_shop3: I had a pin-header-tastrophe :( Are you around? Could I come beg/borrow/steal some more headers?
18:36 rue_house yup
18:36 rue_house would you like to come by?
18:53 rue_shop3 armyofevilrobots, ping
19:12 armyofevilrobots Sorry, yes I would :D
19:13 armyofevilrobots Was in fullscreen mode making Diane’s table into a usable drafting/drawing.
19:19 armyofevilrobots @rue_shop3: ^pingback
19:33 rue_shop3 I'm home for hte evening
19:49 armyofevilrobots OK. I’ll pop over shortly.
22:22 rue_house there is a drive that works like a harmonic drive but dosn't require a cup that gets disorted, who can remmeber or find a reference to it?
22:25 armyofevilrobots gerotor?
22:25 rue_house thats a pump... but...
22:26 armyofevilrobots torchoidal
22:26 armyofevilrobots but I don’t know how well they can be driven backwards...
22:26 armyofevilrobots usually they are good for very close ration reduction, like 50:49 or something like that.
22:26 rue_house hmmm
22:27 rue_house did you remmeber supper?
22:27 armyofevilrobots I did.
22:27 rue_house good show
22:27 rue_house you got back fast
22:27 armyofevilrobots Helen had told me “I want you to get a 5 patty burger. And Imma watch you eat it”. She was joking. I…. I was not :D
22:28 armyofevilrobots Turns out extra patties on a papa burger are only $1 each.
22:28 rue_house heh
22:28 armyofevilrobots and yeah, I ate it.
22:28 rue_house I put a new driver on that axis, waiting for results
22:29 armyofevilrobots Oh. Cycloidal? Kinda like an inside out rx7 engine? http://en.wikipedia.org/wiki/Cycloidal_drive
22:29 rue_house that looks closer
22:30 rue_house ah, maybe that is it
22:30 rue_house harmonic drive without bending anything
22:31 rue_house http://garysclocks.sawdustcorner.com/animation_cycloidal_gears_undercut_radial.gif
22:31 rue_house I think I just learned the trick to finding the pitch radius
22:34 rue_shop3 ok, its not the driver
22:55 rue_shop3 oh I wonder,
22:55 rue_shop3 I have an interesting issue where hooking up one of the fans causes the drivers to randomly step
23:31 rue_shop3 its not losing steps, its adding them, I can hear it
23:35 rue_shop3 I think the error in my test object is in the slicer output
23:45 armyofevilrobots Hmmm, if you have bridging, then you’d get extra steps every time the fan kicks up.
23:52 rue_shop3 they aren't controlled fans, I redid my grounding and I'm noticing a few differences
23:53 rue_shop3 but I'm watching the machine do steps in what should be a straight line
23:53 rue_shop3 I dont know if its the gcode file or the heater
23:53 rue_shop3 http://gcode.ws/
23:55 rue_shop3 ok its not in the gcode
23:55 rue_shop3 so, where are these steps comming from
23:55 rue_shop3 I checked the drivers, turns out I'm not at a fraction of the motors capability
23:56 rue_shop3 so I dialed em up
23:56 rue_shop3 apparently I'm at .5A of 1.2 motor rated
23:58 rue_shop3 correction, these are using .01R and not .02R
23:58 rue_shop3 so I'm at 1A