#robotics Logs

Feb 14 2012

18:43 orlok http://hackaday.com/2012/02/14/arduino-lawn-care-is-web-controlled/
18:44 orlok chopping board!
20:15 trylob In 5 years I want all lawnmowers to be controlled with a playstation controller by RC
20:15 trylob putting a seat, and a steering wheel and all that jazz technically should cost MORE MONEY to manufacture
20:16 theBear interesting point
20:16 trylob The RC lawnmower would look like an old push mower with nothing on top by an engine and a RF antenna sticking out.
20:16 trylob No handlebars... nothing
20:17 Tom_itx or a couple goats
20:17 Tom_itx let them have the grass
20:17 Tom_itx you get milk in return
20:18 Tom_itx perfect for all you friggin tree huggers
20:18 theBear trylob, i know, i seen rue's one ;)
20:19 Triffid_Hunter Tom_itx: problem with goats is they like veggies more than grass
20:19 Triffid_Hunter and they have an unbelievably incredible knack of defeating fences...
20:37 rue_more mine is autonomous
20:37 rue_more I just have to check every so often that its not either humping a shrub or upside down at the bottom of a precifice
20:38 rue_more or digging itself a pit, it does that too
20:38 rue_more Tom_itx, goats = lawn poo
20:38 rue_more and aparently goats eat everytning BUT the grass
20:38 Tom_itx no need to fertilize
20:38 Tom_itx always something
20:39 rue_more I like to lay on my lawn
20:39 Tom_itx when do you have time>
20:39 Tom_itx ?
20:40 rue_more it happens
20:43 Tom_itx man, i'm running out of parts
20:43 theBear and i can't for the life of me find a single fet !
20:44 rue_more no CRT multisync monitors?
20:44 theBear i wonder... low freq switching, maybe 20khz give or take, a big mosfet should be drivable in place of a small one shouldn't it ?
20:44 theBear rue_more, ahh rue, my hero of the junkyard, so yer saying i SHOULD walk across the road and grab that late-model crt ?
20:45 theBear trying to replace one of those err, 1.8*2.8mm smd ones
20:45 theBear heck, that little 15" up there in the cupboard probly isn't worth fixing (gets blurry as it heats up) ... maybe i should just rip the boards out and dump it while there's already a pile of rubbish across the street
20:46 theBear then i would officially own no crts !
20:47 theBear so fets being all super high impedance gates, a somewhat larger one SHOULD be fine right ?
20:47 rue_more multisync monitors use gets to switch horzontal caps
20:47 rue_more usually IRF640
20:48 rue_more sure, try it
20:48 rue_more http://www.facebook.com/photo.php?fbid=10150721326843626&set=a.153023343625.145922.752038625&type=1&ref=nf
20:48 rue_more can you get that?
20:49 rue_more if so, remember, if at first you dont succeed, get new batteries
20:49 theBear heh nice
20:50 theBear irf640 :) it's a big step up, but still
20:50 eBear looks out the front wi
20:50 rue_more GO GET IT!
20:51 theBear grr, who put that stupid tree there
20:51 theBear ok, what the hell, it'll have some other handy stuff, coils and hv transistors and crap i spose
20:55 theBear hmm... do i gotta spark-bang the crt on a modern one, or it has a discharger in there somewhere ?
20:56 eBear pokes the caps on the board with a big screwdriver for a s
20:57 Triffid_Hunter I usually use resistors to discharge the power input filter caps.. the current pulse from a sudden discharge can warp the plates and short them internally
20:58 theBear jeez, they make em cheap these days... there's only one 'tiny' big cap in there
21:04 theBear wow, been a LONG time... someone remind me how to get the flyback sucekr off ?
21:05 rue_more theBear, definitly discharge the tube
21:06 rue_more theBear, the HV things is a double sided clip
21:06 rue_more work out which way its on and push it hard sideways,
21:06 theBear rue_more, what, like just squeeze it ?
21:06 rue_more push sideways to undo one side, then unclip
21:07 rue_more (lift, side other way)
21:07 theBear oh cool... i was thinking get that off with big insulated tools then just put the lid back on and drop it across the street... that bang when you discharge 'em always scares the crap outta me
21:07 rue_more stuff a grounded wire under the cap...
21:07 theBear oh :( ok
21:07 rue_more ground it off to the straps across the tube back
21:07 theBear only cos you insisted, and probably know best
21:08 rue_more if its beenpowered down for more than 2 weeks is prolly dead
21:11 theBear pfft, what an anticlimax, not even a click !
21:11 theBear orright, all back together, i go drop the carcass back across the street
21:14 e_more gig
21:14 theBear BALLS ! stubbed my big toe on the way out
21:14 theBear better have a damned fet in there for me
21:14 eBear goes to inspect the big ugly monitor
21:15 rue_more your gonna get me started on you and being accident prone
21:16 theBear damn, i forgot how much that hurts
21:16 theBear c'mon, first injury in 6 months
21:19 theBear hmmm, so i lookin for a to220, heatsunk ?
21:20 theBear arg stupid big toe... i'm makin a coffee
21:24 theBear ahh, of course, that's the leg i forgot how to use over the last 6 months
21:24 rue_more mmm
21:25 rue_more theBear, they should be by the big caps by the horiz deflector coil
21:25 rue_more deflector coil
21:25 rue_more today that sounds cool
21:25 rue_more deflector coil
21:25 rue_more deflectorrrrrrrrrr coil
21:25 theBear err, aren't all the coils still attached to the crt i just put back out the front ?
21:26 rue_more on the pcb
21:26 theBear got all the neck board and checked the other calibration pcb for no-silicon
21:26 theBear it is ?
21:26 rue_more where the horiz coil plugged into
21:26 theBear hmm, gimme a second
21:26 rue_more there were one or two connectors for the deflector coil
21:26 rue_more s
21:27 rue_more by that there are a few fat bipolar caps
21:27 rue_more by each is a fet, they dont always put heatsinks on them
21:28 theBear i spose once it syncs they are just on or off anyway
21:29 rue_more they just change based on the scan rate
21:29 rue_more keep the flyback in check
21:30 theBear hmm... irf630b
21:30 eBear look
21:31 rue_more 630 640 meh
21:31 rue_more how many you win for the effort?
21:32 rue_more 30/40 is difference in voltage rating iirc
21:32 theBear just one right in there, but several other potentials
21:33 theBear grrr, just found a 2nd one next to a redback, brb
21:33 rue_more redback?
21:34 theBear grrr
21:34 rue_more ?
21:34 theBear you know, very poisonous spider
21:34 rue_more nope
21:35 theBear do spiders tend to live in families in monitors or alone ?
21:35 rue_more I think all spiders live alone
21:35 theBear http://en.wikipedia.org/wiki/Redback_spider
21:35 theBear good, cos i do NOT wanna get bit by one of them
21:36 theBear mmm.... 24hrs of pain they say, i don't want that
21:36 theBear i just come out of 6months of pain, i don't need more
21:37 rue_more http://en.wikipedia.org/wiki/Wolf_spider hmm that just looks like a normal spider to me
21:37 theBear holy crap ! "The Redback spider is one of only two animals to date where the male has been found to actively assist the female in sexual cannibalism. In the process of mating, the much smaller male somersaults to place his abdomen over the female's mouthparts. In about 2 out of 3 cases, the female fully consumes the male while mating continues. Males who are not eaten die of their injuries soon after mating."
21:37 theBear only real identifier is the red strip, otherwise they are much like a normal spider, but much more poisonous
21:37 theBear it's like cobras, everyone is sposed to know about them, even if they never seen one
21:39 rue_more I'm going to the shop to test my overload circuit
21:40 theBear okie dokie, i'm gonna try to stop checking my lap for spiders and maybe replace the worlds smallest fet with a to220 :)
21:40 theBear such a nice pair, i'm tempted to save them for somethign they might actually warm up for :)
21:41 theBear wow, these guys are fascinating, assuming wiki is true :)
21:42 theBear dammit ! i hate times like this, just found a dangerous bug dangerously close to you in something on yer lap, every tickle or itch makes you jump and look for spiders
21:47 Tom_itx :)
22:18 theBear nice, pair of 630s and a single 640 in tehre, and a couple BIG ones
22:18 theBear 800v/1.5r/5.2a and something i haven't looked up yet
22:20 theBear hehehe, you think 18a/200v should be enough to run a few 'pc-fan's ? <grin>
22:24 rue_shop2 the big ones have a gain of 5 or 10, aka USELESS
22:25 rue_shop2 I just found a use for a 555 that has completely nothing to do with timing
22:25 rue_shop2 I needed 1 Rs
22:25 rue_shop2 I needed 1 RS latch and a relay driver
22:27 theBear useless for a lot of things, probly fine for i dunno, playing with flybacks and big switchey stuff
22:27 theBear maybe even have a play with that full bridge + fet style mains switcher (triac alternative)
22:29 theBear wonder what i'll do with a pair of 630's now i got em... wonder if i'll ever stop computering and put this damned thing back together ? who knows...
22:29 theBear gonna run out of supplies and need the shops before long <grin>
22:35 theBear mmm... its ludicrously oversized, but the numbers look good, lets try this sucker
22:43 rue_shop2 whats NE5532...
22:43 Triffid_Hunter rue_shop2: nice op-amp for audio work
22:44 rue_shop2 UGH
22:44 rue_shop2 I demand it be a pin compatible dropin for a 555
22:44 e_shop2 grumbles about not needing mroe op-
22:45 rue_shop2 I dont have 6 555
22:45 rue_shop2 this is stupid
22:45 theBear hehe
22:45 theBear watcha doin ? just make a nice little opamp osc :)
22:47 rue_shop2 no I need it for its RS latch and built in relay driver
22:48 rue_shop2 how the *(&^&%&^% do _I_ not have any 555!?
22:48 theBear c'mon rue, even I got a bunch of 555's, cmos and normal !
22:48 theBear then again, i don't like them as much as you :)
22:48 e_shop2 goes to the tubs, 'i MUST have 6
22:48 rue_shop2 I have a drawr of 556
22:48 theBear well, just cut some in half
22:48 theBear REALLY carefully :)
22:50 rue_shop2 ... lengthwise?
22:50 theBear no silly, it won't fit in the holes then
22:50 rue_shop2 haha I just found a rail of them
22:50 theBear pfft, sip half a 556, i've never heard anythign so silly :)
22:50 rue_shop2 I thought I had totally failed there for a min
22:51 rue_shop2 whats pcf8574?
22:52 theBear erm, that's a tough one, sounds kinda familiar, maybe some kinda (computer) io chip ?
22:56 rue_shop2 the RS latch, latches the overload signal from the op-amps, drives the shutdown relay to kill power to the leg, the discharge pin signals the overload to the computer which can reset it via the reset pin
22:56 rue_shop2 it takes less space than equiv transistors/resistors
22:58 rue_shop2 now here is an interesting thought, do I want to power to the legs to be defalt desconnected on powerup
22:58 rue_shop2 hmmmm
22:59 rue_shop2 its prolly a good idea eh?
22:59 theBear probly
22:59 rue_shop2 less chance of something jumping off the tables during boot
23:00 theBear i did it without isolation off another pcs parallel port, just a resistor and a cap for good luck... sometimes it resets while the other inits the parport during boot :)
23:00 Tom_itx have it jump to attention on boot up
23:10 rue_shop2 next thing being called into question is the 1A dpdt relays I'm using for the 3A of axies
23:10 rue_shop2 hmm
23:11 rue_shop2 I'm prettymuch out of time
23:11 rue_shop2 gonna dig thru boxes for 555's that aren't new I can use up
23:33 theBear hmm... .1ms 2.2 cycles/div ... ummm.... so err, roughly .04ms/cycle, so err, umm, c'mon brain, 1000/.04
23:34 theBear oooh, 25khz, for eyeballing without reading sub-divs, that sounds a lot like the early 20-something khz pwm i was expecting.... i think the fet butchery replacement worked !
23:34 theBear and 16a, damn, that thing'll melt power connector before it blows :)
23:35 theBear i suppose i'd never seen the circuit on the scope AND working yet, but seems even at 25khz the nice square drive across err, 1.1k gate resistor gets awful triangley as it goes in, but i can live with that