#robotics Logs

Mar 17 2015

00:35 rue_house add 4 diodes to shunt it up and down
00:35 Triffid_Hunter rue_house: don't get flyback with an emitter follower
00:37 rue_house hmm
00:37 rue_house I suppose it is held
00:37 rue_house oh I was switching
00:38 Triffid_Hunter need flyback protection when collector connects to the load, but with emitter follower it just goes through the B-E junction of one of the transistors
00:39 rue_house I'm sorry, I was thinking of my switching controller
02:06 MrMobius actually I dont even see how this is supposed to work. I would basically have to create a whole new H bridge outside the motor driver chip. Might as well just use Darlingtons.
02:11 mrdata thell
02:12 mrdata MrMobius, https://www.youtube.com/watch?v=GLFDBAGbtk8
02:13 MrMobius the world lied to me
02:16 MrMobius although everyone else was like "transistors on a motor driver? sounds good"
02:25 Triffid_Hunter MrMobius: if you want a powerful h-bridge, check out the HIP4082 or similar
02:25 Jak_o_Shadows I gotta get a pcb made for that someday
02:25 Jak_o_Shadows my protoboard version failed miserably.
02:25 Triffid_Hunter Jak_o_Shadows: HIP4082?
02:25 Jak_o_Shadows yup
02:26 Triffid_Hunter Jak_o_Shadows: http://imgur.com/a/IDQ5u :P
02:26 Jak_o_Shadows That is a very tiny thing.
02:26 Triffid_Hunter Jak_o_Shadows: yup
02:26 Triffid_Hunter Jak_o_Shadows: the mosfets are good to 15A or so, the PCB can handle that too with a bit of reinforcement
02:27 Triffid_Hunter I blew a track on it the other day, replaced it with a strip of used solder wick
02:29 Jak_o_Shadows yeah.
02:29 Jak_o_Shadows I don't need a motor driver at the moment, but your thing would beo n a list to be onsidered
03:07 deshipu what's with the purple boards?
03:07 Triffid_Hunter deshipu: all oshpark boards are that colour
03:10 deshipu I see
09:16 rue_house usb H bridge?
12:08 crankslider check this out. a new technology (much faster) of 3D printing http://rt.com/usa/241453-liquid-printing-system-faster/
13:07 deshipu crankslider: isn't that exactly how the very first industrial 3d printers worked?
13:07 deshipu the one that is patented into oblivion
13:07 crankslider dunno
14:04 Kasperdk Hello, can anyone provide some input on a path-planning problem I have seen myself blind on?
14:05 Kasperdk Concerns 2d rigid body (x,y,theta) path planning
14:06 Kasperdk In my sampling based algorithm (RRT) I choose a random config and find the closest config already in my tree (euclidean distance), but since my configuration is (x,y,theta) I don't know in which direction to extend/interpolate
14:18 veverak how are called the things
14:19 veverak that allows you to pass 'cables'/'current' to things that are spinning continously?
14:20 Kasperdk http://en.wikipedia.org/wiki/Slip_ring
14:20 veverak thanks a lot!
14:27 veverak hmm
14:27 veverak any tps for spli rings that got hole in the middle?
15:09 deshipu veverak: note that they are usually not suitable for signals
15:09 deshipu veverak: well, not high-speed signals
15:13 Hyratel stoopkid, when are you gonna get a dedicated client?
15:40 veverak deshipu: need more like 'voltage' on led?
15:40 veverak deshipu: maybe PWM ...
15:40 veverak but that should work just fine?
15:46 deshipu veverak: yeah, the pronblem is they tend to be noisy
15:47 veverak https://www.youtube.com/watch?v=sO2-tqoyGik
15:47 veverak it looks awesome
15:47 veverak but I would prefer to make it in way that I would buy 1/2 of parts
15:47 veverak and 3d print the second 1/2
15:47 veverak and just do finish touchers
15:47 veverak *touches
16:24 Hyratel I need to learn Kicad
16:24 Hyratel I really pushed Fritzing way beyond its reasonable abilities with a project I thought was simple
16:28 deshipu yeah, it's simple but limited
16:29 Hyratel I mean
16:29 Hyratel https://dl.dropboxusercontent.com/u/33593534/images/Fritzing/RelayBoard%20for%20StigChristian%20R2A_bb.png
16:29 Hyratel https://dl.dropboxusercontent.com/u/33593534/images/Fritzing/RelayBoard%20for%20StigChristian%20R2A_pcb.png
16:31 Hyratel it's great for planning projects using prefabs
16:31 Hyratel but it breaks down for largert scope projects using components
16:33 deshipu ugh
16:33 Hyratel hm?
16:34 Hyratel I'm downloading Kicad
17:02 Kasperdk Does anyone here know/have experience with motion planning algorithms?
17:04 veverak use dice
17:04 Hyratel don't be an ass
17:05 veverak Kasperdk: udacity got quite a nice course about robotics with nice parts about motion planning
17:09 Kasperdk Yeah I know most of the theory, but I have some theory/implementation trouble
17:09 Kasperdk specifically related to sampling based algorithms (RRT)
17:12 Hyratel general opinion: PDIP-32 or TQFP-32?
21:11 slidercrank https://www.youtube.com/watch?v=n_6p-1J551Y a nice cube :)