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look up videos of the rigol model you are interested in because there are some thorough youtube reviews of scopes
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Jan 7, 2015 22:17
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I really like the look of the rigol 2072 or whichever one is the $800 one with the fast update and density plotting to look like an analog scope EEV blog guy says it's a great "entry level good" dso too so that's a big plus
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Jan 8, 2015 00:09
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Sagebrush posted:I really like the look of the rigol 2072 or whichever one is the $800 one with the fast update and density plotting to look like an analog scope https://www.youtube.com/watch?v=TRy755StMak omfg its a monster
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Jan 8, 2015 00:38
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 that waveform display rate
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Jan 8, 2015 00:39
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 i really want that scope now but i am literally not smart enough to be involved in any project where i'd need something that monstrous
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Jan 8, 2015 00:39
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kwinkles posted:i don't think the edison board ever did this. the first galileo board only had low-speed gpio on expanders, but the current galileo board has 12 high speed gpio pins right off of the SoC and more on an i2c expander. i am pretty sure the edison board has at least that many high speed gpios but i haven't worked with it so i'm not sure and i can't be bothered to look it up. the Edison can be configured for up to 44 GPIO pins, though as always the pins are shared by other interfaces.
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Jan 8, 2015 08:18
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eschaton posted:the Edison can be configured for up to 44 GPIO pins, though as always the pins are shared by other interfaces. this sounds pretty rad. here is what i made with 12 full speed gpios:  
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Jan 9, 2015 06:16
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kwinkles posted:this sounds pretty rad. here is what i made with 12 full speed gpios: sweet! what kind of LED matrix is that? I assume it's i2c?
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Jan 9, 2015 06:21
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eschaton posted:sweet! what kind of LED matrix is that? I assume it's i2c? no its the one they sell at adafruit, it needs more than i2c, i will post the source code in a bit when i upload it. it needs a 3-bit led address, red green and blue values for each LED, and it has to be refreshed many times a screen to display colors.
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Jan 9, 2015 06:24
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i am an idiot forget about this. i broke my internet.
EIDE Van Hagar fucked around with this message at 06:30 on Jan 9, 2015 |
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Jan 9, 2015 06:25
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scope chat: i have an hp 54600b (90s crt dso) and it suits my needs. your fancypants rigol might have fft, but i have tetris. take that.Mido posted:Paging yosposter Raluek, paging Yosposter Raluek gently caress, i dont check yospos over the holiday break and i miss poo poo. just like that. anyway, re: southbay electronics places: halted is alright, their prices are kind of high though. also don't expect them to have anything in stock ever, it's mostly surplus so if you find something you like, you better buy it cause it probably wont be there the next time you're there. unless it's garbage, in which case it will be there forever with a price that is two figures too high. they do have some smt stuff, and aisles and aisles of old through hole components (carbon composition resistors! 85c capacitors!) if you need that poo poo weirdstuff is cool, but more attractive for computery stuff than electronics. havent really found much cool stuff there, unless you like 1U servers. but it's always a good opportunity to ogle the weird poo poo they have in stock. i havent been to anchor electronics yet, next time i go out shopping that way i think i will check them out. overall i guess halted is the best ive found so far, in terms of "ah poo poo i need a handful of passives for my idiot spare time project", and you never know what you'll find there. but there have certainly been times ive left emptyhanded. full disclosure: i used to work at their other store (which was better in almost every way  ) until they closed it a couple years ago. so i may be biased.edit: poo poo i forgot about the flea market during the summer. that is always a good time. de anza parking lot in cupertino, second saturday of the month i think? but only during the summer. starts up again in may i think. gotta get there early or all the real good stuff is gone, although if you manage to find something interesting towards the end of the day you can lowball the poo poo out of people who dont want to move poo poo a second time. Raluek fucked around with this message at 08:42 on Jan 9, 2015 |
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Jan 9, 2015 08:39
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kwinkles posted:this sounds pretty rad. here is what i made with 12 full speed gpios: please tell me theres a speaker too
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Jan 9, 2015 16:40
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hobbesmaster posted:please tell me theres a speaker too you could add a speaker but its just the display right now: https://www.youtube.com/watch?v=Iz_3PlxRLOA 16x32 rgb leds. this video was from testing, it just cycles randomly.
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Jan 9, 2015 19:07
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i feel like you're really missing the full beep-boop experience without a speaker
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Jan 9, 2015 21:17
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You can drive 512 ws2811-type rgb leds at 30Hz with a bog standard avr and a single data line fyi, as long as it has about 2k of ram and >16mhz I.e., an arduino You don't by any means need 12 gpio and an Intel processor
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Jan 9, 2015 21:42
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yeah i really have no idea what on earth quark is for it's built on a super expensive process and is really op for the sorts of things you'd use a microcontroller for
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Jan 9, 2015 22:03
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Sagebrush posted:You can drive 512 ws2811-type rgb leds at 30Hz with a bog standard avr and a single data line fyi, as long as it has about 2k of ram and >16mhz this particular LED panel requires 12 inputs and you have to manually turn every LED on and off, but it's also capable of daisy chaining so you can really drive a lot more LEDs with those 12 pins, you just have to read in the data for the furthest panel, 2nd furthest, and so on until you get to the closest panel. i had two panels hooked up to it at one point and i didn't see any performance problems, i think i am going to do a project eventually with 6-8 panels but this is a fun yosmas gift i thought.
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Jan 10, 2015 00:18
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the gige switch chip I'm working with right now has a neat LED interface, to make it customizable they have all the LEDs run by this little processor that you program in assembly, it has two registers, 2 flags (carry and zero), a few dozen opcodes, and they claim the whole thing is less than 1500 gates. kinda neat. what was not neat was not getting the documentation and having to reverse engineer those opcodes from their example code and trying to figure out what some of the custom assembly ops did. although we finally got the docs today so I guess I could have waited and saved a good few hours of work
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Jan 13, 2015 21:36
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been playing with a we just bought it and got a package deal with pretty much every optional extra included, segmented memory + hardware protocol analyzer is pro as gently caress, record several seconds of serial traffic at 2.5 GSPs and export waveforms + CSV of all traffic like it's no big deal so far pretty much everything i've wanted to do just required some fiddling and yup, it can do it
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Jan 14, 2015 20:09
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imo the best mso money can buy
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Jan 15, 2015 00:02
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so the Intel Edison stuff, with the Arduino board has an Arduino-compatible IDE. how should I go about figuring out what all of the Arduino stuff actually maps to in terms of memory-mapped I/O (or whatever) so I can wire it up to Lisp instead? oh, also, SBCL runs OK on the board. not great, at least in comparison to my MacBook Pro (i7), but acceptably well and probably a lot better than on Raspberry Pi.
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Jan 19, 2015 04:25
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Olivil posted:yo to all my yosbros, frukegate update: ebay gave me my money back  they didn't give me a cheap fluke tho they even did an expedited refund 'in light of the seller's recent activity'
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Jan 19, 2015 21:49
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anyone who thought they were actually going to get a real fluke for $13 was an idiot "yeah it's obviously a scam, but $13 fluke! poo poo i'd better order ten of them"
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Jan 19, 2015 22:16
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if theyre not used to the currency and they're a middle man that only notify a warehouse "this item is paid ship it" it could happen I got a quick refund too
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Jan 19, 2015 22:33
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maniacdevnull posted:frukegate update: What? I got my money back a couple of hours after the account was deleted. Sweevo posted:anyone who thought they were actually going to get a real fluke for $13 was an idiot I think you already made this joke, but I don't remember anyone ordering ten of them. Anyways, there are pricing mistakes or legit clearances all the time on the internet that people score great deals with. With ebay there was literally zero risk to try it, so why not?
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Jan 19, 2015 22:47
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i don't think anyone here did it, but people on a few electronics forums did, and were shocked when the meters that were marked as "shipped" 5 seconds after they purchased them never arrived
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Jan 19, 2015 22:49
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DNova posted:What? I got my money back a couple of hours after the account was deleted. i just opened the claim today, ebay refunded the money minutes after i submitted it was still holding out hope
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Jan 19, 2015 22:49
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yeah there's a guy that ordered like 30 of them anyway i shared it because considering ebays customer protection it was pretty risk free and you'd kick yourself if the listing happened to be a gently caress up
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Jan 19, 2015 23:10
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somewhat unexpectedly a 5V OCXO module showed up in the mail today, just got it installed and tuned in the "new" HP 5335A counter. managed to find the 24V standby that's designed to drive the heaters so it'll stay warmed up when powered off too for $30 it's pretty good, used of course but the supplier was nice enough to write the pinout on the module with a marker pen, even included the "correct" tuning voltage which seems to have shifted a bit during transit keeps around +-1 ppb short term when warmed up, decent enough since the spec was +-30 ppb, a lot of hysteresis in the tuning so it's kind of tricky to adjust very finely kind of disappointed with whoever bought this counter originally, a 10 digit frequency counter with no OCXO is pretty shameful, if they still cost $50 i'd have installed a rubidium oscillator instead
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Jan 23, 2015 23:25
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eschaton posted:so the Intel Edison stuff, with the Arduino board has an Arduino-compatible IDE. how should I go about figuring out what all of the Arduino stuff actually maps to in terms of memory-mapped I/O (or whatever) so I can wire it up to Lisp instead? figured this out! last week I found the source drop on Intel's site that includes the components implementing their Arduino support, which led me to their libmraa low-level C library for interfacing with I/O. just a quick compile against the already-installed headers and library, and I was able to use some C to blink the onboard LED. quote:oh, also, SBCL runs OK on the board. not great, at least in comparison to my MacBook Pro (i7), but acceptably well and probably a lot better than on Raspberry Pi. I also switched from SBCL to CCL for my Lisp, since it's the environment I'm more comfortable in on my Mac and it performs nicely on the Edison too. today I managed to figure out the madness that is CFFI and got a basic wrapper for libmraa's GPIO functionality written. now I can write code:and blink the board's LED for n seconds! next I'm planning to wire up something to a breadboard and just try pushing some pattern of bytes to it as fast as I can and capture a trace with my analyzer, so I can see just what kind of bandwidth I have available (and maybe also check that Lisp isn't adding that much overhead)
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Jan 26, 2015 06:45
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bump
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Feb 1, 2015 05:10
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Bloody posted:bump  tilt
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Feb 1, 2015 08:39
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eschaton posted:so the Intel Edison stuff, with the Arduino board has an Arduino-compatible IDE. how should I go about figuring out what all of the Arduino stuff actually maps to in terms of memory-mapped I/O (or whatever) so I can wire it up to Lisp instead? here's a cool paper about writing code for a space probe back in 1999: Like all spacecraft, DS1 placed constraints on compu- tational and telecommunication bandwidth (both uplink and downlink) resources. For computational resource, DS1 has a total of 128 MB RAM, 16 MB EEPROM, and a 20 MHz RAD6k. During the RAX experiment time, the uplink and downlink data rates were about 1 kbps and 4 kbps, respectively. Based on early estimates, RAX was allocated 32 MB of RAM, 16 MB of file space and up to 45% of the CPU. At the time of this alloca- tion it was not clear if RAX could meet these resource constraints. To fit within the 32 MB memory allocation and the CPU fraction constraints, the RAX team thoroughly analyzed their code for memory and performance inefficiencies and employed a "tree-shaking/transduction" process to the Lisp image. The analysis is, of course, common for any high performance software. However, transduction is Lisp- specific and arises from the tight coupling of the Lisp runtime and development environments. Transduction removes the unneeded parts of the development environment, e.g., the compiler, debugger, windowing system. The result is a significantly smaller image, both in terms of file system and runtime memory. During RAX testing, peak memory usage was measured at about 29 MB, which was more than was actually observed in flight. To reduce the uplink time and the spacecraft file sys- tem usage, we employed a custom Lisp image that sup- ported ground-based compression and spacecraft-based decompression. Upon completion of the transduction process the RAX Lisp image was compressed by a factor of about 3 to 4.7 MB and uplinked to the spacecraft. On-board decompression was initiated at the start of each RAX run, with the file being inflated directly into the 32 MB RAX memory space. Use of this custom compression drastically reduced the file uplink time and kept the RAX file space usage within the agreed upon limits. http://www-aig.jpl.nasa.gov/public/planning/papers/rax-results-isairas99.ps
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Feb 1, 2015 09:43
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welp, my fluke 8520a seems to have bitten the dust. upon powering it on today it put a hardware error on the display, smelled like burning, and then blew the fuse. guess i have to go to halted sometime soon and get some fuses; i dont have a 3ag in half amp onhand. i wonder if theyll have a circuit breaker in such a small current rating. probably not, but cant hurt to dig. trouble is, i cant pinpoint where the burning smell was coming from, so i dont know what has failed. im sure ill go through a bunch of fuses before i figure it out.
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Feb 1, 2015 10:30
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i spent friday night fixing one of my HP 3456As, randomly it would measure 0 ohms with open terminals, but only on the 100k and up range self test threw an error -10, input amp or current source error checking the output voltage on the various ohms ranges showed it produced no output voltage for 100k and up, so obviously nothing would be measured following the 385 page user/service manual I skipped most of the tests and just measured some test point voltages when i found nominal values, in the current source section there's a fairly intricate circuit to generate a wide range of constant currents based on the range, that current is passed through a resistor to measure the voltage across it and indirectly, the resistance the voltage reference test point was spot on for the working ranges and seemed to be hitting a supply rail on the broken ranges here's the list of ranges and currents  the service manual suggested checking some transistors that switch in the two reference voltages, Q201 and 2  this manual seems to have lost some of the little dots that show line junctions, pretty sure U203:2 isn't just connected to a test point for example. anyway, U202 is a quad comparator, HA2 on the input is a TTL signal that's part of the range switching system the purpose is to switch either the -5.5V reference (which is trimmed) or the -9.25V reference through to the rest of the circuitry notice that right in the middle there's some resistors with a line around them, those are precision resistors inside a HP custom hybrid, if that breaks the instrument is junk checking some voltages in here i found that the -9.25V was fine at one end of Q202, but for some reason it wouldn't switch so the 9.25V reference wouldn't get through and no current would flow after dicking around for a bit and trying to remember how a JFET worked, i did some diode tester measurements comparing the two transistors and found there were identical, so Q202 was almost certainly ok as it might not be very clear, the purpose of U202 is to pull the gate of Q201 and Q202 to -18V to completely turn them off, the inputs on the two are inverted so a single TTL signal selects one of the two references finally i used a ohm-meter to measure from the output of U202a and b down to -18V (U202 is a LM339, which has open collector outputs), the b output would switch between 15Mohm and around 40 ohms, the a output would switch from 36 to 39 ohm in the off state.  after checking that the inputs were in fact being set correctly i cut the relevant pin, and the 100k+ ranges worked perfectly, i happened to have around 50 LM339s in my IC box so replacing it was a simple job
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Feb 1, 2015 11:47
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Bloody posted:bump most of my electrical stuff lately has been less "cool projects" and more "learning a poo poo ton of math"
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Feb 1, 2015 13:41
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Tin Gang posted:most of my electrical stuff lately has been less "cool projects" and more "learning a poo poo ton of math" Cool let's talk about math then
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Feb 1, 2015 17:14
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Bloody posted:Cool let's talk about math then did you know that the basic equation describing the attraction between charges has never needed to be corrected in hundreds of years? it is as accurate for systems the size of an atom as it is for entire galaxies take that mechanical engineers! Tin Gang fucked around with this message at 17:31 on Feb 1, 2015 |
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Feb 1, 2015 17:27
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Tin Gang posted:did you know that the basic equation describing the attraction between charges has never needed to be corrected in hundreds of years? it is as accurate for systems the size of an atom as it is for entire galaxies Also, the Pythagorean theorem has never been disproven or needed any additional coefficients added in the thousands of years since it was first created.
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Feb 1, 2015 18:58
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Sagebrush posted:Also, the Pythagorean theorem has never been disproven or needed any additional coefficients added in the thousands of years since it was first created. mathetical proofs are not equivalent to laws of physics!!!
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Feb 1, 2015 19:23
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