#robotics | Logs for 2016-02-09

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[08:59:52] <veverak> deshipu: http://www.aliexpress.com/af/PCA9685.html?ltype=wholesale&d=y&origin=n&isViewCP=y&catId=0&initiative_id=SB_20160209062830&SearchText=PCA9685
[08:59:55] <veverak> that price
[09:01:20] <deshipu> veverak: yeah, finally
[09:01:26] <deshipu> veverak: still a pro mini is cheaper
[09:01:55] <deshipu> veverak: and handles 18 servos :P
[09:02:47] <veverak> wait
[09:02:55] <veverak> deshipu: what was resolution with your code?
[09:02:57] <veverak> it's 12 bit
[09:03:06] <veverak> but for servo range "only" 4 us
[09:06:20] <deshipu> well, I use integers for the position, so 1µs
[09:06:37] <deshipu> I could probably make it less if I needed
[09:06:45] <veverak> aaand update rate?
[09:13:06] <deshipu> 50Hz
[09:13:26] <deshipu> could change it too, but that could affect the precision
[09:14:31] <veverak> yeah
[09:14:37] <veverak> just for comparasion
[09:14:47] <veverak> deshipu: PCA can do only 4us with 60Hz
[09:15:21] <rue_house> nobody wants high resolution or good timing
[09:15:46] <rue_house> and that PCA9685 is less than 7 bit when you REALLY get down to it
[09:16:31] <rue_house> 12bits is 100% duty :P
[09:16:50] <rue_house> anyone could just use my code, but nobody will
[09:18:03] <deshipu> rue_house: be honest, would *you* use someone else's code?
[09:21:12] <rue_house> I'd look over it and if it looked like it wasn't a hack, then yes
[09:22:06] <rue_house> but your about to buy a hardware solution thats less than 7 bits
[09:22:11] <rue_house> cause ITS a hack
[09:22:24] <deshipu> rue_house: I'm not about to buy it, I have my pro mini
[09:23:03] <rue_house> sorry, "your" wasnt literal, your representing the world
[09:23:40] <deshipu> oh, Them
[09:24:24] <rue_house> it you can do mroe than 10 channels on a m328 without timing glitches I'd liek to see the code
[09:25:08] <deshipu> I linked you to the code already
[09:25:18] <rue_house> hmm pls do again
[09:25:38] <deshipu> https://bitbucket.org/thesheep/controller/src
[09:25:45] <deshipu> it's not mine, btw
[09:25:54] <deshipu> I don't mind using other people's code, see?
[09:27:04] <rue_house> as arduino code its NOT possable for that to work right
[09:27:08] <rue_house> really, it isn't
[09:27:48] <deshipu> it's not arduino code, I just added the i2c handling
[09:28:53] <rue_house> ah the .ino file is for another project?
[09:29:59] <deshipu> look at the pwm.*
[09:30:09] <rue_house> currently am
[09:30:33] <rue_house> software, so its low resolution
[09:31:09] <deshipu> jumping to conclusions, eh?
[09:31:19] <deshipu> well, it's 1µs resolution
[09:31:46] <rue_house> no, the communications and pwm cant be handled by that many channels at a good resolution without glitches
[09:32:08] <deshipu> you only have so many timers
[09:32:22] <rue_house> yea
[09:32:34] <deshipu> fortunately communications have buffers
[09:32:59] <jhylands> deshipu, how many timers do you use to handle 18 servos?
[09:43:07] <rue_house> Wire.onReceive(receive);
[09:43:13] <rue_house> that appears to be an interrupt
[09:43:47] <rue_house> tho, the arduino loop is done after other things
[09:45:30] <rue_house> no again...
[09:47:04] <rue_house> why is the phase of the pwm being adjusted?
[09:51:10] <veverak> rue_house: because i don't have use for it
[09:51:16] <veverak> as simple as that
[09:51:18] <veverak> :)
[09:51:39] * veverak needs more channels per one chip than 8
[09:52:05] <rue_house> then you get glitches
[10:06:20] <deshipu> jhylands: one
[10:12:04] <deshipu> jhylands: it's actually quite smart -- it keeps a sorted array of the pulse widths, and in the trigger sets the trigger to the next count
[10:19:46] <deshipu> got the pcb for the espruino-based quadruped assembled
[10:19:53] <deshipu> seems to work this time
[10:21:01] <deshipu> this will be smallest yet
[10:55:49] <nos> https://www.youtube.com/watch?v=uJoBBagewOw
[11:04:50] <deshipu> creative name
[12:06:03] <circuit> hi
[12:06:14] <circuit> anyone using logview/icharger on windows 10?
[12:06:25] <circuit> I somehow don't get any live data updates
[14:25:57] <veverak> anybody any experience with DSO Nano V3 ?
[14:26:04] * veverak would propably like it
[16:14:52] <deshipu> veverak: I have it
[16:14:58] <deshipu> veverak: it's pretty crappy
[16:15:28] <deshipu> veverak: the default firmware is so buggy, it's unusable
[16:16:26] <veverak> damn it
[16:16:30] <veverak> and it could be awesome :/
[16:19:22] <deshipu> there is alternate firmware that I'm using
[16:19:39] <deshipu> but it doesn't work well with the new display and without an sdcard
[16:19:45] <deshipu> which is how the new V3 is
[16:19:57] <deshipu> someone will probably port it soon, though
[16:20:27] <deshipu> veverak: have you seen that logic analyzer made from a beagle bone black?
[16:26:11] <veverak> nope
[16:26:41] * veverak is thinking about something portable to tell him voltage (up to 12V at max), analyze PWM output out of arduino (range of Servos -> 600-2400us and 60hz) and current
[16:26:46] <veverak> I know I can't have it in one device
[16:26:56] <veverak> but nano looked like it could handle first two :)
[16:27:50] <jhylands> veverak, I just bought a LabNation SmartScope
[16:27:57] <jhylands> its pretty cool
[16:28:05] <jhylands> works with a PC or a phone/tablet
[16:29:25] <veverak> and price is not so cool
[16:29:27] <veverak> :)
[16:29:30] <veverak> jhylands: but looks good
[16:30:10] <veverak> hmm
[16:30:17] <veverak> afaik alternative for smarscope would be dslogic thing?
[16:30:22] <veverak> http://www.dreamsourcelab.com/order.html
[16:31:24] <jhylands> the smartscope has both 2 channel scope and 8-channel logic
[16:31:50] <veverak> yeah, I see now
[16:33:42] <veverak> or
[16:33:48] <veverak> maybe fu it
[16:33:56] <veverak> hmm, how reliable is arduino to measure PWM signals?
[16:33:58] <veverak> :)
[16:34:12] <jhylands> the problem is buffering
[16:34:23] <veverak> buffering?
[16:34:27] <jhylands> the arduino has almost no RAM
[16:34:32] <veverak> nah
[16:34:36] <jhylands> so you need to send all the data in real time to the host
[16:34:37] <veverak> measure => send to pc instantly
[16:34:39] <veverak> :)
[16:34:44] <veverak> jhylands: not a problem here
[16:35:04] <veverak> because, with arduino I should be able to somehow check it, measure voltage somehow and current too
[16:35:10] <veverak> even if I would have to use one arduino per job
[16:35:27] <veverak> it could work, would be interesting to do, would be exactly the way I like it and would be much less expensive
[16:35:36] <SorcererX> I have a BitScope Micro, I'm quite happy with it
[16:35:39] <jhylands> I find to analyze fast traffic (like SPI) I need to run my Saleae logic at 16 or 24 MHz
[16:35:54] * veverak wants to analyze only current/voltage/servo pwm
[16:36:13] <jhylands> well, sure, for that you could probably just use a single arduino
[16:36:25] <veverak> well
[16:36:26] <jhylands> how many servo pwms?
[16:36:30] <veverak> maybe multiple for practical reasons
[16:36:37] <veverak> jhylands: at least two is what I wanted originally
[16:36:49] <veverak> but that was only because multiple channel osciloscope is expensive
[16:36:58] <veverak> all of them (14 at the moment) would be much better ofc :)
[16:37:46] <jhylands> you could probably do six with an arduino, if you can use capture/compare on the PWM lines
[16:38:13] * veverak bought 10 arduino pro micro for cheap price
[16:38:19] <veverak> and eve nwilling to buy next batch
[16:38:24] <veverak> so there are enough arduinos
[16:38:47] <jhylands> current is a little more tricky, depending on what resolution you want
[16:39:13] <jhylands> I found to get down to 1 mA resolution, I needed a clean power supply and a 16-bit A/D
[16:39:50] <veverak> 1 mA is overkill
[16:40:06] <veverak> under 100mA would be nice
[16:40:23] <veverak> SorcererX: looks much better pricewise
[16:40:24] <jhylands> yeah, depends on the magnitude you're after as well
[16:40:25] <veverak> :
[16:40:29] <veverak> :)
[16:40:40] <veverak> jhylands: it's for measuring the entire thing
[16:40:42] <veverak> ie, entire robot
[16:40:52] <veverak> (arduino, some servos and it's 5A top)
[16:40:55] <jhylands> so 5 amps is probably plenty
[16:41:10] <veverak> well
[16:41:18] <veverak> it's 3A stable, 5A spike
[16:41:27] <veverak> or, that's the rating of UBEC that makes the 4V
[16:41:28] <jhylands> you just need a current sense op-amp
[16:41:29] <veverak> *5V
[16:41:31] <veverak> :)
[16:41:43] <jhylands> and a decently stable resistor
[16:42:42] <veverak> hmm
[16:42:44] <veverak> ok
[16:42:50] <veverak> for now I can skip the PWM part propably
[16:42:59] <veverak> it's important but there should not be much bugs there
[16:43:09] <jhylands> the pwm part is easy, its just software
[16:43:26] <veverak> I imagine that most of the problems with signal for servos would be bad signal width calculated
[16:43:35] <jhylands> as is voltage (although you'll need a voltage divider if you're trying to measure > 5 volts)
[16:43:36] <veverak> and that's calculated before it's send to arduino in program
[16:43:43] <veverak> so don't have to bother much I suppose
[16:43:58] <veverak> only V/A, and that should be doable with arduino ::)
[16:44:07] <veverak> jhylands: yeah, should not be problem
[16:44:20] <veverak> 12V top rating
[16:44:25] <veverak> ok, let's make it 14V to be sure
[16:44:46] <jhylands> so to measure 15 volts, you need a 15K/5K resistor divider
[16:45:04] <jhylands> actually, that will do 20 volts
[16:45:09] <jhylands> for a 5 volt system
[16:45:23] <jhylands> sorry, last one I did was for a 3.3 volt system
[16:45:28] <jhylands> so we needed a larger divider
[16:45:38] <jhylands> 5K/10K should be enough
[16:45:57] <jhylands> I try and find 0.1% resistors for the dividers
[16:45:57] <veverak> yeah
[16:46:09] <veverak> also
[16:46:12] <jhylands> they cost a bit more, but normal resistors are terrible
[16:46:15] <veverak> hmm
[16:46:23] <veverak> esp8266 got only 1 adc?
[16:46:27] <veverak> I would have to use two :/
[16:46:35] <jhylands> esp8266 is 3.3 volts
[16:46:44] <veverak> that's the smaller problem
[16:46:46] <veverak> :)
[16:47:40] <jhylands> The micropython guys are doing a kickstarter right now with the esp8266
[16:48:02] <veverak> yeah
[16:48:08] <veverak> tried that, would not again for now
[16:48:10] <veverak> :)
[16:48:20] <veverak> it works to some degree, it looks nice
[16:48:30] <veverak> but I will wait propably till it's in more advanced phase
[16:48:34] <veverak> than it will be awesome!
[16:49:20] <jhylands> well, that's the point of the kickstarter
[16:51:21] <jhylands> dinner time, back in a while
[16:52:05] <veverak> :)
[17:05:35] <maiden> and progress is progressing: https://plus.google.com/u/1/115118068134567436838
[17:09:48] <maiden> veverak: http://www.ebay.com/itm/New-USB-Cable-24MHz-8-Channel-24M-Logic-Analyzer-Device-Set-Flux-Workshop-SN-/151850499960?hash=item235afebf78:g:uyYAAOSwT5tWIHNm
[17:10:34] <maiden> veverak: http://www.ebay.com/itm/1pcs-5A-range-Current-Sensor-Module-ACS712-Module-NEW-/381374424345?hash=item58cbafe519:g:k0UAAOSwr81UN9UJ
[17:10:50] <veverak> interesting
[17:10:52] <veverak> :)
[17:11:59] <maiden> i have used the "Current Sensor Module" with the BBB, but i have the 30A version.. the 5A version should have been better for my use...
[17:13:08] <maiden> just to note, i got a real saleae: https://www.saleae.com/
[17:14:57] <veverak> that prices looks good
[17:14:59] <veverak> hmm
[17:25:02] <Snert_> I've often wondered if you can adjust the resistors on those current sensor modules to get a smaller range.
[18:42:01] <veverak> hmm
[18:42:15] <veverak> more I think about it, the more idea of logic analyzer sounds good
[18:42:30] <jhylands> I have an original saleae, and it is so worth it
[18:42:37] <jhylands> saved my ass more times than I can count
[18:42:48] <veverak> it's more like
[18:42:50] <veverak> I don't really need it
[18:42:55] <veverak> it's my hobby that would appreciate
[18:43:10] <veverak> but hey, I am student, last time with enough time to actually play with things and learn
[18:43:12] <veverak> :)
[18:43:46] <veverak> and if I get good enough with these things, range of thinks I will be able to do increases...
[18:44:05] <jhylands> its so nice when you're doing stuff like I2C and something doesn't work
[18:44:12] <jhylands> or even straight serial
[18:44:16] <veverak> exactly
[18:44:18] <veverak> well
[18:44:21] <jhylands> its also good for timing stuff very exactly
[18:44:22] <veverak> usually you can somehow try to debug it
[18:44:28] <veverak> but I suppose it makes things faster a lot
[18:44:30] <veverak> ;)
[18:45:08] <veverak> but, for paycheck I would be able to afford only saleae logic 4
[18:45:20] <jhylands> I've never used more than 4 channels at once
[18:45:26] <jhylands> and 90% of the time I only use 2
[18:45:31] <veverak> and, everything I do is digital
[18:45:56] <veverak> hmm
[18:46:07] <jhylands> there are cheap fake ones on ebay
[18:46:39] <jhylands> but the saleae software is so awesome
[18:46:49] <veverak> hmm
[18:46:52] <flyback> well my new aoyue 2930 struggled on some rohs thru hole today but did way better than the irons before it
[18:47:03] <flyback> also I think I just need a thick tip with thermal mass for thru hole
[18:47:06] <jhylands> I hate rohs
[18:47:13] <flyback> built quality is pretty good
[18:47:13] <veverak> servos got 600-2400 us pulse range
[18:47:22] <flyback> think I am going to repair my old irons mabye mod them
[18:47:25] <flyback> keep them for leaded stuff
[18:47:32] <veverak> 1 us = 10^-6 s ?
[18:47:37] <flyback> so I don't have to buy $15 tips for my new one for leaded stuff
[18:47:43] <jhylands> measuring down to sub-microsecond is no problem with the saleae
[18:47:54] <veverak> jhylands: point is
[18:47:57] <flyback> you talking about that cheap logic probe or whatever it is
[18:48:04] <veverak> that alternative to this is dslogic
[18:48:09] <veverak> which got 16 channels
[18:48:11] <veverak> :)
[18:48:38] * veverak could than make setup where he watches everything at once during debugging
[18:48:41] <veverak> which sounds attractive
[18:48:55] <veverak> but, it means that the device have to be able to handle it, so have to check that out
[18:48:58] <veverak> and also watch references
[18:49:02] <veverak> nah, this will be long process
[18:49:19] <jhylands> yeah, not sure about the software - might be worth downloading it and running in simulation mode (if it supports that)
[18:49:28] <jhylands> the saleae software supports that, in any case
[18:49:46] <jhylands> but it looks reasonable
[18:49:52] <anonnumberanon> sup jhylands have you seen my robot video
[18:49:59] <jhylands> no idea anonnumberanon
[18:50:15] <anonnumberanon> https://www.youtube.com/watch?v=JQdXDg9PtzY
[18:50:26] <veverak> jhylands: they say it's good protocol analyzer
[18:50:29] <anonnumberanon> You're not subscribed?
[18:50:30] <anonnumberanon> heh
[18:50:33] <veverak> i2,SPI,Serial,1-wire
[18:51:21] <jhylands> veverak, yeah, saleae does all that and more
[18:51:31] <veverak> yeah
[18:51:48] <veverak> even on all 16 channels, dslogic got 100Mhz sample rate
[18:51:56] <jhylands> that's handy
[18:51:56] <veverak> and if I count correctly that should handle servos with ease
[18:52:07] <veverak> goes up to 400Mhz on 4 chanels
[18:52:11] <veverak> *channels
[18:55:12] <jhylands> anonnumberanon, it would be nice if you gave some indication of what specifically you're doing to the robot
[18:58:23] <jhylands> I built a GUI to do that sort of thing when I was playing with that kind of robot
[18:58:25] <jhylands> http://huv.com/~bioloid/tiki/show_image.php?id=108
[19:01:04] <veverak> ok
[19:01:06] <veverak> wait a sec
[19:01:11] * veverak realized one must have feature
[19:01:16] <veverak> I need API access to the thing itself
[19:01:24] <veverak> or CLI tool or anything
[19:03:10] <veverak> http://sigrok.org/wiki/Supported_hardware#Logic_analyzers
[19:03:20] <veverak> well, now we are talking
[19:03:22] <veverak> :)
[19:03:35] <flyback> now that I have a new iron I can rebuild my parallel bus flash programmer and make 2-3 more
[19:03:48] <flyback> using old mediatek optical chipset dvd or dvd-rw or cdrw drives
[19:04:03] <flyback> although I eventually want to switch to serprog running on a mcu with a lot of i/o
[19:04:12] <veverak> daaaaamn
[19:04:15] <flyback> since the mediatek will do 512KB max
[19:04:22] <veverak> jhylands: it looks like saleae wins propably
[19:04:29] <flyback> it just abuses "firmware recovery mode"
[19:04:38] <flyback> you can flash pron to a blank chip on startup
[19:07:23] <jhylands> veverak, I have no complaints about mine
[19:07:54] <veverak> jhylands: but, sigrok webpage shows some more alternatives
[19:07:57] <veverak> will look into it
[19:09:12] <jhylands> I haven't done anything to mine - no new firmware, nothing
[19:09:14] <jhylands> it just works
[19:09:27] <veverak> yeah
[19:09:45] <veverak> but I've got the feeling that it may be too good and I could get more channels per same prace which sounds ... attractive
[19:09:48] <veverak> so, reaserach -> decide
[19:09:51] <veverak> :)
[19:10:12] <jhylands> yep - for usb analyzers, it really comes down to how good is the software
[19:10:21] <veverak> yeah
[19:10:28] <veverak> and I itend to use sigrok anyway so...
[19:11:41] <veverak> http://sigrok.org/wiki/Openbench_Logic_Sniffer
[19:11:45] <veverak> NOW we are talking
[19:11:48] <veverak> :)
[19:12:34] <jhylands> cool
[19:12:43] <anonnumberanon> jhylands, yeah, that'll come with the next video, when it can take a step
[19:13:25] <jhylands> anonnumberanon, https://www.youtube.com/watch?v=wOsNJCwrm6Y
[19:13:44] <jhylands> that was MicroRaptor walking, using poses and sequences from that GUI
[19:14:18] <veverak> ok
[19:14:20] <veverak> afaik
[19:14:30] <veverak> we got some alternative of openbench logic sniffer at hackerspace
[19:14:37] <veverak> so, will look into that
[19:14:44] <veverak> hacking FPGA looks fun also, so will see :)
[19:15:05] <jhylands> yeah, that stuff wasn't available when I bought my saleae
[19:15:58] <anonnumberanon> jhylands, yeah my video should be like that if I ever make it, that is, if I don't die.
[19:16:59] <rue_house> needs some rubber feet
[19:17:11] <rue_house> its not walking its ice skating on wood
[19:17:32] <jhylands> yeah, I had some cut out, but never got around to attaching them
[19:22:36] <anonnumberanon> If you get a hold of a set of stronger servos, might be worth a try.
[20:55:32] <rue_shop3> yea, I'm totally overflowing in gears, I need to make lots of servos
[20:57:46] * Tom_itx read that as years
[21:02:52] <rue_shop3> its not far off
[21:22:28] <rue_shop3> I spent 15 minutes making a spring, it flew over here somewhere.. have you seen it?
[21:32:22] <z64555> sorry, I don't have permissions to your webcam
[21:49:47] <mrdata> lets fix that
[22:08:15] <z64555> D:
[22:32:04] <rue_house> theBear, what do I do with like 0.5 degree spot lights?
[22:33:24] <rue_house> hmm they are 6V