azonenberg | Tomorrow night's plan - spin coat a quarter of a <110> wafer in Ta2O5 and bake | 06:14 |
---|---|---|
azonenberg | in preparation for a Cu evaporation run later in the week | 06:14 |
azonenberg | also, run some tests of dilute SC2 etch rate characterization | 06:14 |
azonenberg | see how dilute an etch is reasonably fast but still controllable | 06:14 |
bart416 | azonenberg, we just tried to launch a little small rocket | 13:37 |
bart416 | But it started | 13:37 |
bart416 | raining | 13:37 |
bart416 | lol | 13:37 |
bart416 | And it shorted the triggers for the stages | 13:37 |
bart416 | so the moment we turned on power all stages fired at once :D | 13:37 |
bart416 | things left: first stage nozzle was still on the ground | 13:38 |
bart416 | nose cone a few meters further | 13:38 |
bart416 | well, at least that means the explosive bolts for the first stage nozzle worked | 13:39 |
bart416 | well yeah with bolts I mean rings, lol | 13:39 |
bart416 | we use two rings, with spacing in between them in the middle | 13:40 |
bart416 | and then clip them together | 13:40 |
bart416 | But the system isn't water tight it seems :( | 13:41 |
azonenberg | explosive bolts? What was your separation charge? | 17:45 |
azonenberg | And i wouldnt be sure it's water, could be other interference | 17:48 |
azonenberg | next time try doing a power-on test with empty motor casings | 17:49 |
azonenberg | i'd also strongly suggest a software controlled ignition sequencer of some sort | 17:49 |
azonenberg | Which might allow you to isolate from interference better | 17:50 |
azonenberg | also, try using detonators that are more resistant to EMI | 17:51 |
bart416 | the controllers are ATtinys | 18:29 |
bart416 | and the separation charge was blackpowder | 18:30 |
bart416 | it's powerful enough for this | 18:30 |
bart416 | cause the energy has nowhere else to go | 18:30 |
azonenberg | yeah, it'd work | 18:53 |
azonenberg | And is cheaper/safer/easier to get access to than a high explosive lol | 18:53 |
azonenberg | What did you use as the ignition system? | 18:54 |
azonenberg | One of the problems with black powder is that especially the finer grades are afaik pretty static sensitive | 18:54 |
azonenberg | compared to something like RDX | 18:54 |
bart416 | High voltage spark | 19:11 |
bart416 | we put a small CCFL inverter in the nose cone | 19:12 |
bart416 | and distribute that throughout the rocket | 19:12 |
bart416 | and switch it on when necessary | 19:12 |
bart416 | It's easy, and gets the job done | 19:12 |
bart416 | And its reliable | 19:12 |
azonenberg | Interesting | 19:13 |
azonenberg | Problem is that sounds very ESD sensitive | 19:13 |
bart416 | The entire setup, yes | 19:13 |
bart416 | If water gets in it, it's sort of fucked | 19:13 |
bart416 | High voltage + water + explosives nearby = bad | 19:14 |
azonenberg | i wasnt talking water so much as static | 19:18 |
bart416 | static isn't that problematic | 19:18 |
azonenberg | i think you need a less sensitive detonator and/or an anti-ESD trigger device | 19:18 |
bart416 | all the metal parts are grounded until take off | 19:18 |
azonenberg | not necessarily to the extreme of an EBW | 19:18 |
bart416 | actually until about 5 meters altitude it's grounded | 19:19 |
bart416 | Then the launch wire snaps lose | 19:19 |
azonenberg | interesting | 19:19 |
bart416 | aaaargh, stupid shortcut, lol | 19:19 |
bart416 | anyway, its easy enough to do that | 19:19 |
azonenberg | So what was your problem exactly? | 19:19 |
azonenberg | the water shorted out something in the trigger mechanism? | 19:19 |
bart416 | water got near the electronics | 19:20 |
azonenberg | i see | 19:20 |
bart416 | and short circuited the high voltage | 19:20 |
azonenberg | ... | 19:20 |
azonenberg | yeah, that'd do it | 19:20 |
azonenberg | how were you switching the HV? | 19:20 |
bart416 | cheap relays | 19:20 |
azonenberg | And i bet they werent rated for the voltage? | 19:20 |
bart416 | They are weirdly enough | 19:21 |
azonenberg | Hmm | 19:21 |
azonenberg | well in any case you've now learned about a few of the problems involving explosives | 19:21 |
azonenberg | one of which is that they dont play well with others | 19:22 |
bart416 | I know this is one of the problems :P | 19:22 |
bart416 | I've been doing this for years with a bunch of friends | 19:22 |
bart416 | It's just that it suddenly started raining | 19:22 |
bart416 | so we decided to just go ahead and launch | 19:22 |
bart416 | But water got in the wrong spot it seems | 19:22 |
azonenberg | yeah - if you arent sealed and rain-rated i'd say rain is enough to scrub the launch | 19:22 |
bart416 | well, it only did a few drops | 19:22 |
azonenberg | Hmm | 19:23 |
azonenberg | bad luck then? | 19:23 |
bart416 | it wasn't even really raining yet | 19:23 |
bart416 | I guess | 19:23 |
azonenberg | Its also possible there was a short elsewhere | 19:23 |
azonenberg | unrelated to the water | 19:23 |
bart416 | Unlikely, we check the wiring before we load fuel | 19:23 |
azonenberg | ok | 19:23 |
bart416 | Doesn't matter anyway | 19:23 |
azonenberg | in that case then i guess it was water | 19:23 |
azonenberg | Nothing left of the rocket? :p | 19:23 |
bart416 | Not really | 19:23 |
bart416 | the nozzle and nose cone | 19:24 |
azonenberg | lol | 19:24 |
azonenberg | any damage beyond the rocket itself? Launch pad, spectators? | 19:24 |
bart416 | nozzle was pushed against the ground and it's made out of graphite with a steel ring, so yeah not much that can happen to that | 19:24 |
bart416 | launch pad is a slab of concrete :P | 19:24 |
bart416 | With a steel rod | 19:24 |
azonenberg | i meant the rod and related stuff | 19:24 |
bart416 | no real damage | 19:24 |
bart416 | some scorch marks | 19:25 |
azonenberg | Well, if you can have the rocket literally blow up on the pad and not do any harm | 19:25 |
azonenberg | it seems you picked a good launch site | 19:25 |
bart416 | open field | 19:25 |
bart416 | wet ground | 19:25 |
bart416 | Nothing in the immediate area | 19:25 |
bart416 | We were all standing at 150m distance | 19:25 |
azonenberg | Were the motors APCP or black powder? | 19:26 |
azonenberg | and what was the total magnitude of the charge? | 19:26 |
azonenberg | Most of the rockets i've done are single stage with one class C black-powder motor | 19:26 |
azonenberg | lol | 19:26 |
bart416 | I didn't mix the fuel so not sure what was in it | 19:26 |
bart416 | Probably black powder combined with something else | 19:26 |
azonenberg | Yeah, i dont trust my explosives knowledge far enough to make my own propellant charges | 19:27 |
bart416 | I avoid making my own solid propellants | 19:27 |
azonenberg | i limit myself to premade motors from a respectable company | 19:27 |
bart416 | blackpowder I'll do | 19:27 |
bart416 | in small quantites | 19:27 |
bart416 | worst that you get from small quantites of blackpowder like I mix would be some minor burns | 19:27 |
bart416 | The only rockets where I do the fuel are liquid or hybrid fuel rockets | 19:28 |
bart416 | Else I only do the electronics | 19:29 |
bart416 | This time all I did was provide the launchpad, lol | 19:29 |
azonenberg | lol | 19:29 |
bart416 | It'd be easier if it was destroyed | 19:30 |
bart416 | now I had to drag it home again | 19:30 |
azonenberg | Lol | 19:30 |
bart416 | The only rocket that has destroyed a launchpad up to now was liquid oxygen + kerosene | 19:30 |
bart416 | Damn that was one hell of an explosion, lol | 19:30 |
bart416 | You could feel the heat from a rather considerable distance | 19:34 |
azonenberg | lol | 19:44 |
azonenberg | lox + kerosene? I can imagine | 19:44 |
azonenberg | What was the total propellant mass? | 19:44 |
bart416 | That time, don't really remember | 19:47 |
bart416 | Fairly large | 19:47 |
bart416 | The rocket was 2 meter high | 19:47 |
bart416 | and 40cm diameter | 19:47 |
bart416 | single stage | 19:48 |
bart416 | We launched a few of those | 19:48 |
bart416 | If there's ever a civil war I know what I'm going to use to take out a small armored vehicle... | 19:48 |
bart416 | The issue is, the range of our radio is roughly 600 meter | 19:49 |
bart416 | it went higher than that | 19:49 |
bart416 | so we can't really be sure | 19:49 |
bart416 | But of the 6 we launched in total 2 came back to the ground in one piece | 19:50 |
bart416 | First 2 exploded on the pad | 19:51 |
bart416 | (bad mixing ratios + not enough cooling) | 19:51 |
bart416 | third one acted weird | 19:51 |
bart416 | Huge inferno | 19:51 |
bart416 | We thought it exploded | 19:52 |
bart416 | but it started lifting anyway | 19:52 |
bart416 | But exploded a few meters of the ground | 19:52 |
bart416 | Fourth one broke up on decent | 19:52 |
bart416 | (bad parachute attachment) | 19:52 |
bart416 | fifth launch was a large succes | 19:52 |
bart416 | sixth launch we used the same one as fifth with some replaced parts obviously | 19:53 |
bart416 | But it started showing wear | 19:53 |
bart416 | So we scrapped it | 19:53 |
bart416 | That was our liquid + kerosene adventure | 19:53 |
bart416 | That was totally illegal | 19:53 |
bart416 | lol | 19:53 |
bart416 | Hence why no pictures or videos are posted on the internet | 19:53 |
bart416 | Already had enough complaints due to noise | 19:54 |
bart416 | We then switched to liquid oxygen + ethanol | 19:54 |
bart416 | Far more stable, but a lot less propulsion | 19:54 |
bart416 | but a lot less wear on the engine parts | 19:55 |
bart416 | azonenberg, just heard something rather wow o_O | 20:40 |
bart416 | A friend of mine works at TI | 20:40 |
bart416 | And his wife can't get kids due to cancer in the past | 20:40 |
bart416 | And TI covers legal costs o_O | 20:41 |
bart416 | (They're adopting a kid) | 20:41 |
azonenberg | Thats rather nice of them (TI) | 21:04 |
azonenberg | Lol | 21:04 |
azonenberg | And yeah, i never looked up the regulations re liquid propellants | 21:04 |
bart416 | Well, strictly speaking launching any rocket we built is sort of borderline illegal | 21:07 |
bart416 | We generally cover ourselves under the rather allowing fireworks laws in Belgium | 21:07 |
bart416 | Here it's perfectly legal to buy a stack of fireworks and store it on your attic | 21:07 |
bart416 | Yay! | 21:08 |
bart416 | All you need is an identity card stating you're 18 years or older | 21:08 |
bart416 | Also they (TI) seem to have a lot of programs/benefits like that so they can keep their staff for their entire carreer | 21:10 |
swkhan | hello =) | 21:30 |
azonenberg | Hi | 21:30 |
azonenberg | So whats this about memristors? | 21:30 |
azonenberg | I'd suggest you start large | 21:30 |
swkhan | i want to pattern a bottom electrode and a top electron quickly, cheaply, and easily | 21:30 |
azonenberg | My focus right now is on MEMS so i've been putting a lot of work into bulk micromachining of Si | 21:31 |
azonenberg | as well as metal layers | 21:31 |
swkhan | i see | 21:31 |
azonenberg | http://i.imgur.com/ty4lq.jpg is one of my recent experiments | 21:31 |
azonenberg | nyanotechnology ;) | 21:31 |
azonenberg | Might be the smallest nyan cat made to date | 21:31 |
swkhan | omg so cute | 21:31 |
azonenberg | 200um high and 600 long | 21:31 |
azonenberg | pixels are 20um square | 21:31 |
azonenberg | this is 100x magnification | 21:32 |
azonenberg | he's patterned in about 2um of SP24 photoresist over 200nm of copper | 21:32 |
swkhan | you made that at home? o_O | 21:32 |
azonenberg | evaporated onto a glass substrate (microscope cover slip) | 21:32 |
azonenberg | Almost | 21:32 |
azonenberg | I did the copper deposition in a lab on campus | 21:32 |
azonenberg | all of the lithography, as well as the photoresist deposition, was at home | 21:32 |
swkhan | i work in a lab on campus too but it doesn't have all the facilities i'd like | 21:32 |
azonenberg | I overetched a bit (notice the green areas expanded beyond the holes in the mask) | 21:33 |
azonenberg | turns out even five seconds in full strength SC2 is overkill for going through a couple hundred nanometers of Cu | 21:33 |
azonenberg | i'm gonna dilute it like 50:1 for the next etch (tonight) so it's slow enough to be controllable | 21:33 |
azonenberg | I'm also having issues with focuser drift on my microscope objective | 21:34 |
azonenberg | over the 10-ish minute exposure the stage will move down by a couple of microns | 21:34 |
azonenberg | and blur really small features | 21:35 |
azonenberg | i get good results with the 10x objective (so my 200um laser-printed mask becomes 20um per pixel) but the 40x is blurred beyond usability | 21:35 |
azonenberg | Which school is your lab at btw? I'm a PhD student at RPI | 21:36 |
swkhan | well we're at nasa ames. it's a weird collaboration with a lot of different universities | 21:36 |
swkhan | i know a friend who will be going to RPI next year =) | 21:36 |
swkhan | it's a weird collaboration because everyone just gives the facade of collaborating but doesn't actually take many steps to actually get work done | 21:37 |
azonenberg | Lol | 21:40 |
azonenberg | And nice. whats he studying? | 21:40 |
azonenberg | I did my undergrad work at RPI too (computer science) | 21:41 |
azonenberg | graduated last spring and i'm now just starting my doctorate | 21:41 |
azonenberg | But most of my work, as you can probably tell, is leaning toward the EE side of things | 21:41 |
swkhan | i think he's studying materials science | 21:42 |
azonenberg | In that case he'll probably be playing with the same SEM and evaporator i've been using | 21:43 |
swkhan | ooh | 21:43 |
azonenberg | RPI has more than a handful of SEMs | 21:43 |
azonenberg | there's a zeiss supra 55 FESEM in the cleanroom (which is expensive to get on but the best on campus) | 21:43 |
azonenberg | right next to it there's another zeiss, dual beam SEM / FIB | 21:44 |
swkhan | wow a fib | 21:44 |
azonenberg | then outside the cleanroom inthe mat sci department there's an old jeol tungsten-filament SEM, a newer jeol FESEM | 21:44 |
azonenberg | a TEM | 21:44 |
azonenberg | raman spectrometer | 21:44 |
swkhan | wow | 21:44 |
azonenberg | the cleanroom has an AFM | 21:45 |
swkhan | wow a cleanroom afm | 21:45 |
azonenberg | http://www.rpi.edu/dept/cie/mncr/index.html | 21:45 |
azonenberg | Lots of toys - great as long as you arent the one paying for it | 21:45 |
azonenberg | http://www.rpi.edu/dept/cie/mncr/microscopy.html | 21:45 |
smeding | wish i could play in our university clean room (DIMES at Delft UT) | 21:46 |
smeding | but that will have to wait until at least the M. Sc i suppose | 21:47 |
azonenberg | I actually got in as an undergrad but it was for an outside consulting project | 21:47 |
azonenberg | and just for SEM imaging of a sample | 21:47 |
azonenberg | Anyway so re memristors - i'm reading a bit on them now | 21:49 |
azonenberg | What exactly are you trying to build? | 21:49 |
azonenberg | Lol. this is probably the most interesting artwork i've ever put on a PCB | 22:22 |
azonenberg | A scale drawing of a CMOS ring oscillator | 22:22 |
azonenberg | bottom copper = diffusion, top copper = metal 1, silkscreen = poly | 22:22 |
smeding | hmm :p | 22:23 |
azonenberg | http://i.imgur.com/YqjYV.png | 22:32 |
azonenberg | this is missing vias and body connections, plus all of the other fun stuff you'd need for a real circuit | 22:32 |
azonenberg | But as artwork it should wortk nicely | 22:33 |
azonenberg | oh, the gates on the NAND2 at right should be taller *fixes* | 22:33 |
bart416 | smeding, you're at TU Delft? | 22:34 |
smeding | not currently | 22:34 |
smeding | i'm in between my first and second year of the B. Sc EE | 22:35 |
bart416 | Where are you at? | 22:35 |
smeding | i live in Noordwijk because living with the | 22:35 |
smeding | 'rents is cheap | 22:35 |
azonenberg | Here we go http://i.imgur.com/k8BCm.png | 22:35 |
azonenberg | Complete with two little pics at top right | 22:36 |
Action: azonenberg doesnt like empty space in PCBs | 22:36 | |
smeding | me neither! all that copper just dissolving into your etchant, such a waste | 22:36 |
smeding | silly PCB artwork is good for the environment! | 22:36 |
azonenberg | lol | 22:37 |
kristianpaul | considering crosstalk between layers.. well :) | 22:37 |
azonenberg | Well i'm not making the board myself - its a 4-layer design | 22:37 |
kristianpaul | oh | 22:37 |
azonenberg | 3.3V and ground planes are in the middle | 22:37 |
bart416 | smeding, you're not answer my question | 22:37 |
azonenberg | marked by + and - vias | 22:37 |
bart416 | Are you enrolled at Delft or not? | 22:37 |
smeding | bart416: i just said, i am | 22:38 |
azonenberg | kristianpaul: any overall thoughts on the board? | 22:38 |
smeding | bart416: however, don't even have my P yet | 22:38 |
smeding | close though :p | 22:38 |
bart416 | Just answer yes if people as if you're there >_> | 22:38 |
kristianpaul | pic32 is to load bitstream? | 22:38 |
bart416 | Also why the hell are you complaining then | 22:38 |
bart416 | At least you guys have the equipment to do something | 22:38 |
smeding | hm? | 22:38 |
azonenberg | kristianpaul: Lol its overkill for that | 22:38 |
bart416 | We have to beg for new oscilloscopes >_> | 22:38 |
smeding | i was... complaining? | 22:39 |
azonenberg | the plan is for the pic32 to be the main CPU and the FPGA to be a GPU | 22:39 |
azonenberg | as well as offloading heavy computation to it | 22:39 |
bart416 | "<smeding> wish i could play in our university clean room (DIMES at Delft UT)" | 22:39 |
bart416 | ^Sure sounds like it :P | 22:39 |
smeding | not so much a complaint as something i would like to do at some point | 22:39 |
kristianpaul | pci32 is U1 right? | 22:39 |
smeding | it looks like fun, anyway | 22:39 |
azonenberg | Yes | 22:39 |
azonenberg | fpga is U2 - 200k gate spartan-3a | 22:40 |
smeding | but yeah, facilities are definitely very, very good | 22:40 |
azonenberg | in 100vqfp | 22:40 |
azonenberg | U5 and U6 are 1A linear regulators | 22:40 |
kristianpaul | i dont see to much wires between board fpga and pic, os i asume trougput is low? | 22:40 |
kristianpaul | s/to/too | 22:40 |
azonenberg | for the 3.3 and 1.2v rails | 22:40 |
azonenberg | and actually its an 8-bit parallel bus | 22:41 |
azonenberg | which could be clocked at up to 40 MHz | 22:41 |
kristianpaul | he i jsut countent a nibble ;) | 22:41 |
azonenberg | Its not a 64-bit bus or something like that | 22:41 |
kristianpaul | 8 bits seems okay then | 22:41 |
azonenberg | heck, the whole pic is only 64 pins | 22:41 |
kristianpaul | sure sure | 22:41 |
azonenberg | They do have a 100 pin version with a 16 bit parallel port | 22:41 |
azonenberg | but realistically i dont need that much bandwidth | 22:41 |
azonenberg | when i outgrow this board in a few months / a year ish i'll do a 6- or 8-layer design with a 256FTBGA fpga and a softcore CPU (no external MCU) | 22:42 |
azonenberg | and a few hundred megs of SDRAM | 22:42 |
kristianpaul | the sram of the fpga is enought for you app i guess too | 22:42 |
azonenberg | Yeah, i considered an external ram but couldnt route it on 4 layers while also having the IO resources i wanted | 22:42 |
azonenberg | the main purpose of the fpga is to run the video output | 22:42 |
azonenberg | 800x600 VGA in text mode | 22:43 |
azonenberg | curses-type interface | 22:43 |
kristianpaul | that GPIO is what for? | 22:43 |
azonenberg | Seemed a shame to pay $100 for three 4-layer boards and not get access to all the FPGA pins :P | 22:43 |
azonenberg | so i figured i'd break 'em out to a ribbon connector in case i needed them for something in the future | 22:43 |
kristianpaul | considering is just video out vias cross under it.. | 22:43 |
azonenberg | this is meant to be a "play around" board, its not for any specific purpose | 22:43 |
kristianpaul | ah ok | 22:44 |
azonenberg | They're gonna be relatively low speed signals | 22:44 |
azonenberg | and there's power and ground planes between themn | 22:44 |
kristianpaul | :) | 22:44 |
azonenberg | everything is single-ended on this board | 22:44 |
azonenberg | except for USB | 22:44 |
azonenberg | the v2 design will be using more differential stuff like TMDS video | 22:44 |
kristianpaul | he, the cap smile footprint :) | 22:44 |
azonenberg | that isnt a cap | 22:45 |
azonenberg | its just a smiley | 22:45 |
kristianpaul | lol | 22:45 |
azonenberg | i like throwing little pictures in that last unused few mm^2 of a board | 22:45 |
azonenberg | note the stuff under it? Not hooked up to anything either | 22:45 |
azonenberg | thats a 7-stage CMOS ring oscillator :P | 22:45 |
kristianpaul | hum i missed usb, is the CONSOLE? | 22:45 |
azonenberg | top copper = metal1, silkscreen = poly, bottom copper = diffusion | 22:45 |
kristianpaul | and yeah, usbon pic32 is host nice | 22:46 |
azonenberg | and actually, both console and keyboard | 22:46 |
kristianpaul | well no more toughts :) | 22:46 |
azonenberg | console is going to an FT232 usb-serial for debugging before i get the video card working | 22:46 |
azonenberg | the keyboard connector is for a standard usb keyboard | 22:46 |
azonenberg | The ultimate plan is to be able to run PICnix on this board without a PC at all | 22:46 |
azonenberg | console interface with usb keyboard and vga out | 22:47 |
kristianpaul | (ring osc) yeah :) | 22:47 |
azonenberg | Recognizable? | 22:47 |
kristianpaul | yes | 22:47 |
azonenberg | Its just a little inside joke for anyone who's studied VLSI and looks at the board lol | 22:47 |
kristianpaul | i first tought was for RF or something then read you comments | 22:48 |
azonenberg | You cant see in this CAD view but i even cut holes in soldermask where i'd put vias to metal 2 or test points | 22:48 |
azonenberg | i usually throw artwork on most of my boards if i have space | 22:48 |
azonenberg | i threw the smiley on two other boards already | 22:49 |
azonenberg | i stuck a companion cube in the CAD for one but the customer scrubbed the project before prototype fab | 22:49 |
azonenberg | the osc is six INVx1 and one NAND2x1 lol | 22:50 |
kristianpaul | bbl | 22:51 |
--- Sun Aug 7 2011 | 00:00 |
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