#robotics Logs

Feb 21 2014

03:18 Jak_o_Shadows http://letsmakerobots.com/node/40399 Cool design. Probably a fair advantage over mecanum wheels, which while they work, but this is cool
09:14 rue_more dont like heat based muscles
17:04 Ademan So I want to have a semi-autonomous robot outside within a rectangular region (think roomba), but there's nothing to reliably use rangefinding against. I was thinking of setting up 3 or 4 retroreflective surfaces one at each corner of the rectangle (3 rather than 4 so that it always has some orientation information). Then I'd give it some sort of light emitter/receiver which allows it to get the direction to each of the points
17:04 Ademan Is that stupid? Are there way better ways to accomplish that?
17:23 chris_99 you could also make it sense a line which would be on the floor in the shape of a rectangle maybe
17:28 Tom_itx have it navigate from the stars
18:03 chris_99 haha
18:04 chris_99 have you guys seen google's project tango
18:04 chris_99 that could be amazing
20:20 MrCurious where is gushh
20:44 robotustra_ are you missing him?
20:47 MrCurious hold me...
20:47 MrCurious no i want to share the good news i shared with you with him...
20:47 MrCurious derp
21:00 micsun anyone heard of willow garage?
21:01 MrCurious yes. they closed
21:25 peepsalot hello, anyone here experienced with bending sheet plastic such as acrylic?
21:39 rue_more yes
21:39 rue_more apply too much heat, bubble and scortch it, I'm quite experianced
21:45 Tom_itx rue_more do you know anything about 'best' or 'first'?
21:45 rue_more I know about FIRST
21:46 Tom_itx $$$
21:46 rue_more yea
21:46 Tom_itx i think best is similar but less
21:46 rue_more whats best? Balmy Engineers for Supreme Technology?
21:48 Tom_itx http://bestinc.org/
21:48 rue_more maybe burning the roommates old sheets would have been easier, but I wouldn't want to be responcable for the resulting reaction
21:50 rue_more BEST (Boosting Engineering, Science, and Technology)
21:57 rue_more I cant do anything when I'm this tired
22:02 Tom_itx sure you can
22:02 Tom_itx sleep
22:34 rue_more armyofevilrobots, I messed up didnt' I?
22:35 rue_more need to build fire alarm loop tester
22:35 rue_more hmm
22:44 peepsalot rue_more, i ordered a bunch of resistance wire to build a little bending jig, but then someone pointed out this thing, http://www.usplastic.com/catalog/item.aspx?sku=37542&gclid=CMfZt6XZyrwCFUxp7AodeTcAfw
22:45 peepsalot so now i'm torn between setting up a power supply capable of running this bare wire, or just getting that little heater strip
22:45 peepsalot i was going to build somehing like this http://www.youtube.com/watch?v=wVEf7PfuKxo
22:46 peepsalot the wire requires about 20V@8A to get dimly glowing, which is what seems to be recommended
22:51 rue_more I think you will have more uck witht he nichrome, it takes about 200c or so to get it to soften though
22:51 rue_more ooo nice bender
22:53 rue_more I pull my nichrome wire out of dead hair driers
22:55 rue_more not often I see a project that I dont see a million improvements to
22:55 peepsalot this 20Ga wire i got is thick as hell
22:56 peepsalot and its Kanthal fwiw
22:57 peepsalot rue_more, that video recommends getting the wire just dimly glowing, which i think is much hotter than 200C
22:58 rue_more yea, goes faster if the source is hotter than your target
22:58 peepsalot yeah. i wish that strip heater said what the damn wattage is
22:59 rue_more have to see about making one of those tommorw
22:59 peepsalot rue_more, so my problem now, if i stick with the kanthal wire, is how i should go about powering it
22:59 peepsalot i don't like the idea of using a variac
22:59 rue_more variac is fine
22:59 rue_more its just a heater
23:00 peepsalot i want to host this tool at my hackerspace and i wouldn't want someone to be able to crank it all the way to 120V and pop the wire, and also deal with dangerous voltages on exposed wire
23:00 rue_more even a dimmer on a low voltage (like 30V or so) would work fine
23:00 rue_more well yea, you dont go full 120 on it
23:00 rue_more a) isolate b) drop
23:00 rue_more use a transformer
23:00 rue_more variac into transformer, output to filament
23:01 peepsalot also, variacs are expensive
23:01 rue_more if you dont already have one use a light dimmer
23:03 peepsalot i think 24V max would be ideal
23:03 rue_more yea he's scarry with the direct 120 on that
23:03 rue_more peepsalot, for heavy guage, maybe
23:04 peepsalot any recommendation where to get a 120->24V, 240VA transformer?
23:05 rue_more well
23:06 rue_more if you cant find a surplus control equipment transformer, rewind an old microwave transformer
23:06 peepsalot i don't know any good electronic surplus places in my area :-/
23:06 rue_more know a recycling place or industrial area?
23:07 peepsalot i was considering getting a 24V 10A DC poewr supply from ebay for like $30, but then would still need something to adjust power
23:08 rue_more get an adjustable one...
23:08 peepsalot well i don't see many of those, i think they would be much more expensive?
23:09 rue_more the 36V 10A I got was about $30
23:09 rue_more it was adjustable down to 5 or less
23:12 peepsalot where did you get that
23:18 rue_more china
23:18 peepsalot most of the ones i see on ebay have a little bit of adjustment, but that just to trim it, can't drop it down significantly
23:20 peepsalot like +-10%
23:20 rue_more http://www.ebay.ca/itm/AC-110-240V-to-DC-12V-10A-120W-Regulated-Switching-Power-Supply-Transformer-/390568649715
23:20 rue_more see the adjustment pot?
23:20 rue_more mines goes down to 5V
23:21 rue_more http://www.youtube.com/watch?v=LIHTECH5ObM
23:21 rue_more hmmm
23:26 peepsalot rue_more, it says on one of the pics +-5% adjustment range
23:27 peepsalot i think yours is more of an exception than common thing
23:29 rue_more http://www.ebay.ca/itm/36V-350W-10A-Universal-Regulated-Switching-Power-Supply-for-CCTV-Led-Radio-/270818028966
23:29 rue_more that one looks a lot more like mine
23:29 rue_more http://eds.dyndns.org/~ircjunk/projects/newpower/p1050871.jpg
23:32 peepsalot yeah, i don't see the adjustment range listed for that one. would rather not purchase on a hunch
23:33 rue_more I can dig and find the same one I got
23:33 rue_more right now its been archived
23:34 peepsalot i sent a question to the seller
23:37 rue_more 291015063681
23:37 rue_more is the item number
23:37 rue_more easyshopping678 | Feedback Score Of 69501 | 98.2%
23:37 rue_more '0~24/10/36V 8.3/10/15/16.5/30A Switch Power Supply'
23:38 rue_more http://www.ebay.ca/itm/291015063681
23:38 rue_more the 36V, 10A one
23:38 rue_more ~$40
23:39 peepsalot now we're talkin!
23:40 peepsalot can't believe i've never found these fully adjustable ones all the times i've searched power supplies on ebay
23:40 rue_more http://www.youtube.com/watch?v=NPLWxxyIJcE aha, prestretch
23:42 rue_more hmm I need those 600V furnace coils I passed up
23:42 peepsalot rue_more, seriously thank you for finding that!
23:42 rue_more I was quite amused it went down so low
23:47 peepsalot ordered! i went with the 24V 15.6A model
23:47 rue_more I think they only varry slighty,
23:49 peepsalot er it was 16.7A from the same listing, they just have different power options http://www.ebay.com/itm/291015063681
23:49 rue_more yup
23:49 peepsalot they all say 0 to xxV
23:50 peepsalot oh, i think i misinterpreted, your "vary slightly" :-P
23:50 rue_more maybe it was just 5V I decided to stop
23:50 rue_more oh yea, I mean the designes are prolly just different transofrmers and diodes
23:50 peepsalot the voltage should vary fully
23:51 peepsalot yeah
23:51 rue_more http://www.youtube.com/watch?v=2FyYF4NxQoI
23:51 rue_more why is there a human in this video?
23:58 peepsalot rue_more, by the way i heard you have done some stuff with air muscles?