#robotics Logs

Aug 10 2014

02:16 rue_shop2 <rue_shop2> didn't even use a driver transistor
02:16 rue_shop2 <rue_shop2> 5.01V, rock stable (not tested to much current tho)
02:16 rue_shop2 :)
02:16 rue_shop2 but the 3842 only goes down to 2.5V
02:16 Jak_o_Shadows http://www.youtube.com/watch?v=DfznnKUwywQ&feature=share is cool
02:16 rue_shop2 so I have to work out how to make an arrangement for going down to 0
02:22 rue_shop2 neat
02:26 GargantuaSauce rue_shop2: do the last 1V of drop or so with a linear regulator?
02:26 GargantuaSauce will eliminate the switching ripple also
02:27 rue_shop2 nonono
02:29 rue_shop2 the controller can do 0%,
02:29 rue_shop2 one of the methods is to move the controllers ground down 2.5V
02:29 rue_shop2 but I have other ideas
02:31 rue_shop2 I'm also thinking that using a controller chip is a bit silly, but I cant get my normal pwm circuit up to 100Khz
02:31 rue_shop2 and this one is happily ticking away at 250Khz
02:44 rue_shop2 or an external comparitor
02:49 rue_shop2 haha I'm falling asleep!
02:51 rue_mohr2 the uc3842 only goes to 95% duty
02:51 rue_mohr2 I didn't use the TL494 because it only goes to
02:52 rue_mohr2 ..96%
02:52 rue_mohr2 maybe I should look at the tl494 again
02:55 rue_house I want 30V out, I have up to 36 available
02:56 rue_house so 83+% is ok
11:02 robotustra http://www.instructables.com/id/Make-Flexible-Circuit-Boards-Using-A-3D-Printer/step9/Other-Possibilities/
11:29 rue_house hmm tl494
11:32 robotustra PWM for power supply
11:32 robotustra why do you need it?
11:35 Tom_itx efficiency
11:58 rue_mohr2 its analog, 0% chance of it locking up
11:59 rue_mohr2 and unlike the ul3842, its comparitor is not locked to 2.5V
12:03 rue_mohr2 http://volpinprops.blogspot.ca/2010/06/budget-build-mini-vacuum-former.html
12:03 rue_mohr2 hmmm
12:03 rue_mohr2 I think I'll do mine, completely different
12:11 Tom_itx no surprise there
12:13 Tom_itx i would hesitate to put those elements that close to the wood
12:13 rue_mohr2 I'm thinking a metal frame lined with concrete board
12:14 Tom_itx at least the part near the elements
12:14 Tom_itx the rest could be wood
12:15 rue_mohr2 I'm out of room int eh shop, mine has to be weatherproof
12:16 Tom_itx make room in the shop
12:16 Tom_itx half that crap you really don't need
12:16 Tom_itx honestly....
12:16 rue_mohr2 I'v done that too many times, there is none left
12:16 Tom_itx build a bigger shop
12:16 rue_mohr2 it'll be the lower floor of the new house
12:16 rue_mohr2 1200'^2
12:17 Tom_itx it will end up being the whole house
12:18 rue_mohr2 nope, I'm putting minor living provisions in the new shop
12:18 rue_mohr2 I'm not gonna work int eh house, I'm gonna live in the shop
12:18 Tom_itx a chair?
12:19 rue_mohr2 couch, tv, coffeetable, bar fridge, tea machine
12:19 rue_mohr2 hmm, SCR has the gate off the cathode
12:20 rue_mohr2 this needs one of those ones with the gate off the anode
12:20 rue_mohr2 whats that called now
12:56 rue_mohr2 PUT, its called a PUT
13:06 Tom_itx never heard of it
13:44 rue_mohr2 PUT and UJT are realated
13:49 robotustra pute de merde
14:30 robotustra rue_mohr2: building new house?
15:15 cambazz2 hello. when using dc brushless motors, is there anyway to have a driver that would eliminate the need for encoders?
15:26 Tom_itx inductive feedback
15:26 Tom_itx ?
15:33 Hyratel cambazz2, doubtful
15:33 Hyratel oh, brushless?
15:33 ratel read bru
15:33 Hyratel cambazz2, you get a sensored motor and a sensored driver
15:34 robotustra https://www.youtube.com/watch?v=ykBnFywRZYE&feature=youtu.be
15:34 robotustra printed a bracket
15:35 robotustra for rack
15:38 rue_mohr2 cambazz, you have questions pending
15:39 Hyratel rue_mohr2, what kind of materials do you have on hand for to build a vacuuformer
15:45 cambazz2 Hyratel: any recomendations for a sensored motor and driver?
15:45 cambazz2 and any recomendations on any dual-motor drivers that does current sensing for each channnel?
15:47 Hyratel I've never even seen dual brushless drivers
15:47 Hyratel but go on hobbyking.com
17:11 anonnumberanon https://www.youtube.com/watch?v=uIaPYj399VI
17:36 rue_mohr2 Hyratel, I have the element from a dryer
17:36 rue_mohr2 I ahve elements from stoves
17:36 rue_mohr2 I have a bunch of light angle iron from an old server cabinet
17:36 Hyratel the dryer element might be overkills
17:36 rue_mohr2 cambazz, did you hear the inductive feedback suggestion?
17:36 rue_mohr2 Hyratel, not at 1/4 power
17:36 Hyratel aha ok
17:37 Hyratel how are you power limiting
17:37 rue_mohr2 1400W or so
17:37 rue_mohr2 thermal regulator
17:37 Hyratel oh, cyclic power?
17:37 rue_mohr2 might just grab something from china that can do a 300c or so
17:37 Hyratel or just thermal thresholdcutoff
17:37 rue_mohr2 yea
17:37 rue_mohr2 dosn't need to be fancy
17:37 Hyratel you could use a (sufficiently high-amperage) Triac circuit for it
17:38 rue_mohr2 not much point
17:38 Hyratel it's just a resistive load and those take well totriac control
17:38 rue_mohr2 I'm just playing with how to make the heating box
17:38 rue_mohr2 I dont know if I want to use the open dryer element or the insulated stove element
17:39 Hyratel dryer elements are meant for forced air heating
17:39 rue_mohr2 at 5500W they didn't even slump
17:39 rue_mohr2 I suspect they wouldn't have a problem with 1400w
17:39 Hyratel so you might need a blower with it. stove elements are built asradiant
17:39 Hyratel you need a radiant heater for this
17:40 rue_mohr2 kinda
17:40 rue_mohr2 its all IR light
17:40 Hyratel bare nichrome has poor IR projection
17:40 Hyratel that's why oven/stove elements are shrouded
17:41 rue_mohr2 I see your point
17:41 Hyratel the inner wire heats up and gets the airspace or electricall insulation glowing red hot and that transfers to the shell which does the actual radiating
17:41 rue_mohr2 well, the radiation vectors way it all
17:41 rue_mohr2 say it all
17:42 Hyratel stovetop elements with an aluminum reflector would do well
17:42 Hyratel also an alu 'diffuser'
17:42 rue_mohr2 I like the stove element cause of the electrical insulation
17:42 rue_mohr2 no worry about a spark show
17:43 rue_mohr2 I was polling google, there seem be a a variety of both
17:43 rue_mohr2 I suspect its hard to go so wrong it downs't work
17:46 rue_mohr2 http://volpinprops.blogspot.ca/2010/06/budget-build-mini-vacuum-former.html
17:46 rue_mohr2 I have a propane tank for a vacuum accumulator
17:47 rue_mohr2 and a compressor thats good for sucking
17:47 rue_mohr2 er, hmm, come to think of it, a few
17:47 rue_mohr2 I ahve some that aren't good for more than a few psi,
17:47 rue_mohr2 technically a vacuum is only 14 psi
17:48 rue_mohr2 I'm gonna go grocery shopping
18:18 Tom_itx rue_mohr2
18:18 Tom_itx bring back something good for me too
18:41 rue_mohr2 I brought back cookies, but theres only half as many in the package as there's supposed to be, so I'm keeping it for me
18:42 Tom_itx you ate your half on the way back!!
18:45 rue_mohr2 no, they packed it with a lot of air space
18:45 Tom_itx they tricked us!
18:49 rue_mohr2 its ok, I came out all right
18:49 rue_mohr2 :P