**** BEGIN LOGGING AT Mon Aug 27 03:00:00 2018 Aug 27 08:11:52 is there an official mechanical outline drawing for the pocket beagle in a machine-consumable format, e.g. DXF, SVG? Aug 27 08:11:59 I only found PDFs Aug 27 08:12:53 I need something that I can import into a PCB layout program to define board outline, location of extension headers, mounting holes ... Aug 27 08:23:57 jkridner: ^ Aug 27 08:30:19 thinkfat: just checking, you've seen the repository contents here? seems quite a few things including a 3d model. https://github.com/beagleboard/pocketbeagle Aug 27 08:33:50 tbr: the stuff in this "Fritzing" subfolder might be usable after edit Aug 27 08:33:56 whatever "Fritzing" is ... Aug 27 08:34:26 some rather weird "design" software Aug 27 08:35:02 My First PCB software ;) Aug 27 08:36:58 this screenshot says a lot => https://upload.wikimedia.org/wikipedia/commons/4/4d/Fritzing-screenshot.png Aug 27 08:37:24 it's kind of a neat concept Aug 27 08:38:42 yes Aug 27 08:38:48 kind of Aug 27 08:39:01 but that means unusable for my purposes Aug 27 08:40:10 what about that AutoDesk step model in models/? Aug 27 08:41:13 https://github.com/beagleboard/pocketbeagle/tree/master/KiCAD/plots seems to have outlines and such Aug 27 08:42:51 yes, gerbers and PDF, drill files etc Aug 27 08:42:57 and a couple of pdfs Aug 27 08:43:32 well I guess I could just import the whole Kicad project and stop all the stuff I dont need... Aug 27 08:43:40 but the approach is somehow "backwards" Aug 27 08:43:43 .. Aug 27 08:44:19 but it looks like I could open the step model in freecad and then export it as 2D DXF... Aug 27 08:44:22 that might do the trick Aug 27 08:46:29 for the beaglebone black I found a DXF in some forum... nothing official either... Aug 27 11:01:21 Hi. I am a newbie for bbb, used some RPI3 and other platforms. I tried to reach the elinux site, but it seems to be down. Aug 27 11:01:48 is there any mirror for that site? Aug 27 11:02:42 I have connected 2 webcams with my BBB. They are appearing in lsusb. I am using fswebcam to test the images. first camera(video0) is capuring image and i can view it. But second camera (video1) is not capturing images. I am getting following error while running fswebcam command 'Timed out waiting for frame!" than "No Frame captured"'. Please let me know about solving this issue Aug 27 11:15:43 Hi again. Aug 27 11:15:43 I got disconnected and might have missed any answer regarding elinux site? Aug 27 11:16:40 actually, no Aug 27 11:17:06 I'm not aware of a mirror for elinux.org either. Aug 27 11:17:31 thanks. Aug 27 11:17:57 likely, you'll have to wait for the site to come back. I guess there's some maintenance going on. Aug 27 11:18:07 all beaglebone site links direct me to the elinux site, so I now way to start Aug 27 11:19:10 it's not down, it looks like they changed the mediawiki version, and the site can't load Aug 27 11:22:58 lol, fail Aug 27 11:23:31 I don't know who's responsible for elinux.org, but presumably they'll fix this soon enough Aug 27 11:26:19 they're probably in the process of upgrading stuff or something Aug 27 11:26:55 based on a quick twitter search it seems elinux.org was still working yesterday Aug 27 11:27:46 it worked two days ago. yesterday around this time it wansnt Aug 27 11:27:50 okay Aug 27 11:28:23 do you know any other place where I can start from? Aug 27 11:28:44 what do you want to know? Aug 27 11:29:13 I want to start with the kernel sources. does https://github.com/beagleboard/linux.git is the correct place? Aug 27 11:29:27 you want to build a custom kernel? Aug 27 11:29:27 any special things I need to know for cross-compilation of the kernel? Aug 27 11:29:31 yes Aug 27 11:29:38 easiest way is using rcn's build scripts Aug 27 11:29:58 where can I find them? Aug 27 11:30:21 (I am familiar with cross-compilation, as I played with RPI3 and other AM335x based boards) Aug 27 11:30:22 https://github.com/RobertCNelson/bb-kernel for the -bone kernel series, https://github.com/RobertCNelson/ti-linux-kernel-dev/ for the -ti kernel series Aug 27 11:30:36 select branch for the exact series desired Aug 27 11:30:52 copy system.sh.sample to system.sh and tweak contents to taste Aug 27 11:31:14 bb-kernel is empty nowadays Aug 27 11:31:22 no it's not, you just didn't pick a branch Aug 27 11:31:57 then run ./build_deb.sh to build a debian package Aug 27 11:32:15 it'll give you an opportunity to tweak the kernel config (by running make menuconfig) Aug 27 11:32:30 oh. Thanks... Aug 27 11:32:42 and what about the git repository I mentioned? Aug 27 11:32:51 what would be the difference? Aug 27 11:32:52 that contains a snapshot of the patched kernel tree Aug 27 11:33:23 what do you mean? Aug 27 11:33:33 while the repositories I linked to contain the patches and build scripts, and will produce a patched tree (like the one you linked to) from a mainline tree and the patches Aug 27 11:33:48 oh. ok Aug 27 11:33:55 Thanks. Aug 27 11:34:18 And one more question, can you tell which DTB is being used for BBB? Aug 27 11:34:44 depends on whether u-boot overlays are used or not Aug 27 11:35:16 for a start, I want to take the sources "from the box", before I start tweaking it... Aug 27 11:35:39 maybe just insert some "printk" to identify my own code Aug 27 11:35:39 note that if you only want to tweak the dts then you don't need to recompile the kernel Aug 27 11:35:43 ok Aug 27 11:36:13 yeah in that case just first build an unmodified kernel, then make changes in the KERNEL subdirectory it creates (the patched kernel tree) and run tools/rebuild_deb.sh Aug 27 11:36:26 don't run ./build_deb.sh again since that will recreate a clean tree Aug 27 11:37:33 i have several tweaks to do.... as I intend to add peripherals for on the expansion headers and then add drivers for them... Aug 27 11:38:49 if u-boot overlays are not enabled then it'll use am335x-boneblack.dts on the BBB. if u-boot overlays are enabled (they are by default) then I think it uses am335x-boneblack-uboot.dtb and applies various overlays to them based on the settings in /boot/uEnv.txt Aug 27 11:40:58 Looks like I still have a lot to learn about all this... :) Aug 27 11:41:14 Where can I find if overlays are enabled? Aug 27 11:41:41 enable_uboot_overlays=1 Aug 27 11:41:45 in /boot/uEnv.txt Aug 27 11:43:25 thanks a lot... Aug 27 11:43:38 i will start my journey with the bbb now... :) Aug 27 11:43:54 also if you're booting from sd card rather than eMMC I recommend erasing eMMC (sudo blkdiscard /dev/mmcblk1) Aug 27 11:44:29 just a random bit of advice to avoid a source of confusion people run into a bit too often ;) Aug 27 11:46:01 that's why I add some big prints in my sources... :) Aug 27 11:47:13 that won't help for this problem, the issue is that if an old u-boot is present on eMMC then it'll probably correctly load your kernel and boot linux, but it will fail to understand most other directives in /boot/uEnv.txt including everything related to u-boot overlays Aug 27 11:47:54 (rom bootloader prefers to load u-boot from eMMC over sd card, while u-boot prefers to load linux from sd card over eMMC. this is the source of confusing situations) Aug 27 11:50:37 ok Aug 27 11:50:46 that sounds a rather good reason Aug 27 11:51:02 but as long as I don't change the u-boot, just the kernel itself, there is no problem, right? Aug 27 11:52:06 yeah it was just random advice in case you're booting a recent image from sd card while eMMC still contains an old image, which is a frequently-encountered situation Aug 27 11:52:44 flashing a recent image onto eMMC is the best fix for that situation, but erasing eMMC is the alternative in case it's desired to actually boot from sd card for some reason Aug 27 11:53:02 it wasn't specifically related to what you're doing Aug 27 11:53:18 once my version would be stable, I guess I'd flash it to the eMMC/.. Aug 27 11:55:12 I generally work from eMMC entirely. worst case if the system doesn't boot anymore at all I just boot from an sd card, mount eMMC and fix the uname_r variable in /boot/uEnv.txt to point back to a working kernel Aug 27 11:56:15 tip: you may want to append a line to version.sh in the build repo to give your custom kernel a suffix that distinguishes it from the normal one, e.g.: BUILD+=-custom1 Aug 27 11:56:37 that would be a good idea Aug 27 11:57:04 Yet, I think I'd prefer to manually build stuff, rather then use automatic tools that I have no idea what they do... Aug 27 11:58:13 sounds like undue hassle.. the scripts work quite well Aug 27 11:58:42 I bet they do. call me oldfashion, I like "knowing" what's going on behind the scene ;) Aug 27 11:59:29 I can understand that, but I've found it pretty convenient to just be able to run a script and get debian package, plus it makes it easy to stay in sync with rcn's kernels Aug 27 12:00:52 but ultimately it's up to you to find a workflow you're comfortable with of course Aug 27 12:01:39 I guess, after a while, I would switch to these tools. but as a start I prefer not to.. Aug 27 13:18:36 m Aug 27 15:08:31 thinkfat: still need a mechanical drawing? Aug 27 15:08:55 jkridner: for the pocket beagle, yes, that'd be awesome Aug 27 15:09:59 https://github.com/beagleboard/pocketbeagle/tree/master/models is a mechanical model... Aug 27 15:10:24 but I can probably provide Fusion360 source, maybe do a 2D DXF extract? Aug 27 15:10:27 what is needed? Aug 27 15:10:36 jkridner: DXF would be cool Aug 27 15:11:07 jkridner: I tried exporting the step file into DXF using FreeCAD, but I fail to make it Aug 27 15:11:34 jkridner: something's always amiss, some dxf-library can not be found and I can not install it Aug 27 15:12:18 jkridner: I only need the board outline with the location of the connectors Aug 27 15:12:39 jkridner: it seems the board has no mounting holes, the the connectors will be enough to make a cape, I guess Aug 27 15:48:42 the centers of the inside rows are 900mil (0.9") Aug 27 15:49:11 I think I should just make a simple dimensioned drawing Aug 27 15:49:19 and put it in the SRM. Aug 27 16:27:29 use the gerbers if you just need a PCB outline Aug 27 16:28:37 you can convert that to DXF or SVG Aug 28 00:53:49 Otay! Aug 28 00:53:56 Say, say, say. Aug 28 00:57:44 I have a L298 motor driver and do you think it is okay to power the L298 motor driver w/ a 12v 3.3Ah battery if my pins are all associated w/ output on the BBB? There are no input pins from that power source, i.e. 12v Lead Acid. Aug 28 00:57:58 ... Aug 28 00:58:13 Damn it. I know I typed that incorrectly. Aug 28 00:59:16 Okay. 12v 3.3Ah to L298 driver and then all leads go from the BBB to the L298 driver as outputs. Not as inputs. Aug 28 00:59:32 Ah! Aug 28 00:59:59 The BBB has another power source. Aug 28 01:03:51 I think I am going back in time here but, "As long as the BBB does not have an input from that specific battery, the 12v 3.3Ah, things are not going to frizzle fry. Aug 28 01:05:12 I know...boring. Aug 28 01:07:34 Forget it. I am a bit slow right now. Aug 28 01:09:17 Slow.. Aug 28 01:09:55 Yes. Aug 28 01:10:29 GenTooMan: Does the 3.3Ah have anything to do w/ the L298 driver? I am asking b/c I do not want to burn my chip. Aug 28 01:11:18 I have a 12v 3.3Ah battery but I cannot find where the amps cranked per hour could cause harm or be harmful. Aug 28 01:11:28 3.3Ah means that the battery will deliver 3.3A for 1 hour that's just capacity. The thing you must be of keen interest is voltage 12V and the outputs and inputs and the relation. Aug 28 01:12:28 Right! Aug 28 01:12:41 That is all. So, if the driver can handle 50v, I am covered. Aug 28 01:12:54 That is the max. volt rating. Aug 28 01:13:18 I just wanted to make sure there was no way of this 12v supply entering my BBB. Aug 28 01:13:39 ... Aug 28 01:13:57 That little chip is a bad mudda but I have a push button. Aug 28 01:14:11 I might use this push button on another set of software examples. Aug 28 01:14:42 Thank you. Aug 28 01:15:37 The input of the push button has no way to connect to the 12v of the battery b/c of it not being set up on the L298 driver, heh? Aug 28 01:16:26 The push button is solely on P9.4 and P8.8 only. Aug 28 01:17:03 Okay. Here goes it! Aug 28 01:19:05 Boy...that LED never had shown so brightly. Aug 28 01:19:12 HA! Aug 28 01:21:50 It was those stinking terrible batteries. This is awesome! Aug 28 01:22:00 My software is a runnin'. Aug 28 01:23:02 Fuse... Aug 28 01:23:11 Geaux motors, geaux! Aug 28 01:23:20 Fuse? Aug 28 01:24:22 so you were in the state of discharge? Yeah I like a slow blow fuse at normal current rating of the motor or a fast blow for peak currents. Aug 28 01:24:44 So you don't cook anything as you feared. Aug 28 01:25:09 Oh. Aug 28 01:25:15 I think I understand. Aug 28 01:25:26 I have no fuses. Aug 28 01:26:58 I will have to check the schematic again but I do not have any fuses on the outside of the motor driver. Aug 28 01:30:12 well in normal systems fuses exist so extreme pyrotechnics don't occur. Just keeping you aware of why things are the way they are. If you are careful and are working at energies sub 30W you aren't likely to hurt yourself badly. Aug 28 01:30:51 Good to know. I usually keep things below 24v. Aug 28 01:34:05 I have some tiny geared motors anyway. Nothing too severe could happen? At last...geared motors, battery drainers, are hopping. Aug 28 01:39:01 https://pastebin.com/sBizG52f is the software I am running right now w/ a 12v battery and this L298 motor driver: https://store.open-electronics.org/L298DRIVER?search=L298. Aug 28 01:39:09 BBB! Aug 28 01:40:31 I can never remember how to get Wattage out of the rest of those three items, i.e. power, voltage, and ohms. Right? Aug 28 01:40:47 I will look it up once more. Aug 28 01:41:37 39.6! Aug 28 01:41:41 I might be in trouble. Aug 28 01:42:01 Big bang theory no longer is on the TV and not in my room. Aug 28 01:42:09 Hahahhaah. Aug 28 01:43:01 I have to say that the BBB works as normal and this motor driver, not a reseller, can handle some power. Aug 28 01:44:15 excuse me...but it can handle 39.6 WATTS! Aug 28 01:44:30 I better look that up again. Aug 28 01:45:15 Ut oh! Aug 28 01:46:35 Heh GenTooMan: How in the hell can this driver handle 50v and only 25w? Aug 28 01:46:47 That is sort of backwards, right? Aug 28 01:48:22 50V * .5A is 25W? Aug 28 01:48:45 I just checked my battery of 12v and 3.3Ah. That brings me to 39.6w but if I had a 24v battery at 1.3Ah, it would be 31.2. Aug 28 01:48:49 Still too much. Aug 28 01:48:50 Oh! Aug 28 01:49:01 I got you knwo. Aug 28 01:49:08 knwo = now Aug 28 01:49:31 12 * .5 is 6W Aug 28 01:49:35 so the resistance of the L298 comes into play how hot it gets. Aug 28 01:49:41 GenTooMan: Where have you found a 50v 0.5Ah battery? Aug 28 01:50:37 I can only use a 12v 1.3Ah battery. At least, I have found these batteries to be available easily around here. Aug 28 01:50:50 Oh. Aug 28 01:50:51 Okay. Aug 28 01:51:35 GenTooMan: I could have erected into dust earlier. This battery is too much for this motor driver. Aug 28 01:51:44 Yikes! Aug 28 01:53:14 Wait. I was reading dissapation. Oops! Aug 28 01:55:54 Dissapation is beyond my understanding. Aug 28 01:56:31 So, how much heat dissapates is how the chip can or will refuse to react? Aug 28 01:57:19 For instance, w/ the BBB, the chip gets too much heat dissapation, the chip stops being accessible. Aug 28 01:59:47 So lets understand 2 things I^2R law and the Forward voltage in a BJT. If you are running .5A through a device and it's resistance is 1 ohm that is about 0.25W because 0.5^2*I is 0.25. Aug 28 02:00:15 Okay. Aug 28 02:00:50 If you have a BJT whose VCE is about 0.3V (IE at saturation in drops 0.3V across it) at 0.5 amp it disapates 0.3*0.5 (V*I = W) Aug 28 02:01:25 VCE? Aug 28 02:01:28 or 0.15W so that's how calculate dissipation in the driver. Aug 28 02:01:36 Thank you. Aug 28 02:01:50 VCE = Voltage Collector to Emitter in a BJT Aug 28 02:01:58 Oh. Aug 28 02:02:42 So, in one end and out the other (w/ change). Aug 28 02:02:48 Yea! Aug 28 02:02:58 Right .. see no rockets involved! Aug 28 02:03:02 GenTooMan: Thank you. Aug 28 02:03:12 No rockets! Aug 28 02:03:55 GenTooMan: Should I look for those specific names when attempting to understand more about my little driver? Aug 28 02:08:26 yes set_ look for resistance vs current or VCE vs (forward voltage drop?) current Aug 28 02:08:41 That will help you not get things a bit hot. Aug 28 02:09:17 Okay. Aug 28 02:09:27 Also the 3.3Ah battery will run longer so that's is a good thing. SLA (Sealed Lead Acid) batteries like trickle charging so just put it on a charger after you are done experimenting each time. Aug 28 02:09:43 Okay. Yea boy! Aug 28 02:09:51 I got one of them. Aug 28 02:10:25 I found my books on this subject! Aug 28 02:26:54 Those would help anyhow sleep says I go that direction night Aug 28 02:40:47 3.3Ah * a 100uF 10v capacitor = 33.0W. This is by far too much dissipation for my needs = boom makers. No! Aug 28 02:41:42 Nope. I have to find out the VCE of my capacitor now. Aug 28 02:46:03 impossible peligro! **** ENDING LOGGING AT Tue Aug 28 03:00:02 2018