#robotics Logs

Jul 13 2015

01:56 rue_house I have a universal joint, and I'm actuating it with 3 cablse instead of 4
03:20 rue_bed WHO THE HELL MEASURED THE TOQUE IN FOOT-KG!?!?!
03:22 deshipu who the hell still uses non-metric system
03:23 rue_bed all of the usa
03:23 rue_bed and the bits of canada that have to work with the usa
03:23 mrdata ugh
03:24 mrdata foot-kg is unacceptable
03:24 mrdata may as well use a staqndard viking oar
03:25 rue_bed maybe you would like cm-lbs?
03:25 rue_bed lb-cm
03:26 rue_bed the mecha design is comming along well
03:26 rue_bed I'm confident I'll have atealst one hand done before I die of old age
03:27 rue_bed it can be a legcay for someone to send to the scrapyard cause they have no clue what it is
03:34 Jak_o_Shadows foot-kg is horrible
03:35 Jak_o_Shadows lb-cm is worse, because lb-force or lb-mass?
03:46 rue_bed I seem to be at that point where I'm slipping between being awake and nodding off
03:55 deshipu Jak_o_Shadows: kg is also a unit of force and mass
03:57 Jak_o_Shadows kg is a unit of mass
03:58 Jak_o_Shadows and for that matter, lbf is a unit of force, with the unit of mass being slug
04:00 deshipu https://en.wikipedia.org/wiki/Kilogram-force
04:01 deshipu and that's the unit used in torque specs
04:02 Jak_o_Shadows Well, as a non-standard unit, it should die.
04:06 deshipu well, wake me up when you get rid of inches and farenheit
04:06 deshipu then we can talk about non-standard units
18:44 rue_shop3 but the USians ( the people who live in the country without a name) want to keep their imperial measurement system
18:47 ace4016 not all of us :P
18:48 rue_shop3 appologies, I meant as a political body
19:04 ace4016 true. if you try converting the US to metric/SI, you'll get an uproar that the liberals are trying to take over
19:10 ace4016 i believe you can than Reagan for that :P
21:52 bostonmacosx good evening
21:52 Jak_o_Shadows yo
21:53 bostonmacosx so I'm building or attempting to build a simple 4 wheeled cart which will travel along a solid track...
21:54 bostonmacosx I have an estimate of 20-30 lbs of force to move it. It need to get up to 5MPH maximum
21:54 bostonmacosx it will have some resistance
21:55 bostonmacosx but that is taken into account in the 20-30 lbs
21:58 bostonmacosx It also need to stop at each end of the track
21:59 Jak_o_Shadows Does it need to be powered on the track? Is like a pulley system feasible?
21:59 Jak_o_Shadows ie. is the track straight?
22:04 bostonmacosx cart should be self powered
22:05 bostonmacosx track straight and 50m longest length
22:05 Jak_o_Shadows What's your actual question?
22:06 bostonmacosx I'm debating what typw and power of motor
22:07 bostonmacosx There is DC with an encoder or a stepper motor or a servo motor...
22:08 Jak_o_Shadows DC motor
22:08 Jak_o_Shadows Through, I question the need for an encoder
22:08 Jak_o_Shadows DC motor because you have a decent size power/speed requirements
22:08 Jak_o_Shadows anyway, can you not sense the ends?
22:24 bostonmacosx it would be hard to sense the ends ..I will have two cameras already tracking movement around the device
22:25 Jak_o_Shadows Can't use push buttons of some kind?
22:25 bostonmacosx but a DC motor will "wind" down
22:25 bostonmacosx so it will still have momentum at the end of the track
22:26 Jak_o_Shadows springy push button on a stick?
22:26 bostonmacosx I was thinking encoder
22:26 Jak_o_Shadows also, it's probably more that the cart has momentum rather than the push-button
22:26 Jak_o_Shadows also, you could just use a brake.
22:26 bostonmacosx then I could stop the motor after a certain number of revolutions...
22:27 bostonmacosx and reverse its direction
22:27 Jak_o_Shadows Yeah, you could. TBH though, you could almost do this whole thing without a uC
22:28 bostonmacosx yeah I'm just wondering how the push button would work...
22:29 Jak_o_Shadows Make it sort of actuated by a long hinged lever
22:32 bostonmacosx what about a normal switch that would "flick" when it got to a certain point in the track. If the switch is open the motors work in one direction. If closed then they only run in the other
22:46 zhanx Jak_o_Shadows, yes i did to answer your mythtv question but that computer is now DOA
22:47 Jak_o_Shadows well done