EEVblog #450 - Ebay Unboxing - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: April 05, 2013, 10:15:15 am
content: Dave unboxes a random bit of gear from ebay. What is it?Spoiler:http://bit.ly/11lzphL

author: Cognito
author_rank: Newbie
timestamp: April 05, 2013, 01:19:12 pm
content: Interesting bit of gearOn the video it seemed like the CRT was lagging by 2-3 seconds before the phosphor lost its color.Is it inherent for that type of CRT or is it just because it's old?Also; would it be possible to do a entanglement experiment with this kind of gear?

author: nitro2k01
author_rank: Frequent Contributor
timestamp: April 05, 2013, 01:33:49 pm
content: I noticed that too. Maybe the display brightness is turned all the way up and that's why.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: April 05, 2013, 01:57:40 pm
content: Wow, very poor packaging. Don’t think I would have accepted it if I had to pay a premium priced for it. But for 50 bucks guess it is hard to complain. I bought a Sencore CS-61 scope off eBay that was packaged poorly. Found the front bezel cracked and the trace was shaky once turned on. Cost me 200 bucks plus 50 for shipping. When I opened the case found a connected had fell off one of the bottom boards. Plugged it up and the scope worked fine for 2 years. But now giving me a problem I have to research.Can’t wait to see the tear down Dave.Interested in what the inside looks like, especially the bent area.

author: Fezder
author_rank: Regular Contributor
timestamp: April 05, 2013, 02:39:48 pm
content: hey, nice unboxing video, terrifying example of how-not-to-pack-package....and, other notice, i remember when i was opening something, took little bit too long knife or pushed it too far, result: nice scratch on otherwise black metal case...i saw victorinox's logo on your knife, good choise Dave, their steel is excellent, only that its pretty hard to sharp, but pays off in its durability.i kind of disliked when you cutted cardboard with it, perhaps i'm just over-protecting my own knives, i use carbon steel one for cardboard, sorry, dont hate me for that note Dave. but, i'd love to see what's inside of that.

author: firewalker
author_rank: Super Contributor
timestamp: April 05, 2013, 02:56:10 pm
content: How much could you sell it?Alexander.

author: HarryWeston
author_rank: Newbie
timestamp: April 05, 2013, 03:49:01 pm
content: Dave, one of the items that came up on the screen , at 8 mins 36 secs, as you pressed the buttons, was "Operating Hints" ....

author: Rufus
author_rank: Super Contributor
timestamp: April 05, 2013, 03:56:54 pm
content: Send the seller this example

author: grumpydoc
author_rank: Super Contributor
timestamp: April 05, 2013, 04:13:21 pm
content: Ouch!

author: Fezder
author_rank: Regular Contributor
timestamp: April 05, 2013, 04:15:26 pm
content: Quote from: Rufus on April 05, 2013, 03:56:54 pmHmm, i wonder did he keep he's job when/if boss saw that?

author: Rufus
author_rank: Super Contributor
timestamp: April 05, 2013, 04:26:27 pm
content: Quote from: Fezder on April 05, 2013, 04:15:26 pmHis mistake would be getting videoed. I doubt the package handling within depots is much different. Fragile stickers and this way up arrows are worthless. You need inches of shock absorbing material around anything and more if it is fragile.Assume anything you send could be dropped on a concrete floor from a height of 6 feet and you will probably be OK.

author: Fezder
author_rank: Regular Contributor
timestamp: April 05, 2013, 04:29:22 pm
content: Quote from: Rufus on April 05, 2013, 04:26:27 pmyeah, thats true allright :S...

author: fthebest
author_rank: Newbie
timestamp: April 05, 2013, 04:29:46 pm
content: Nice instrument. I'm attending a master in particles physics and we have scalers in the laboratory but, as I can see, this one is more complicated and has data analysis capabilities.A scaler is just a pulse counter, for counting photons or whatever particle you want a detector is needed. In this particular unit you can set a threshold value for the input signal, every time the input is above (or below some detectors generate negative outputs) the threshold the scaler count a pulse. In this one you can select a time bin and it gives you the number of counts in every bin, the trigger signal is a start signal for the acquisition and the timer used in the time bins.IMHO you need a particle detector if you want to do something interesting, at least a photodiode.Flavio

author: grumpydoc
author_rank: Super Contributor
timestamp: April 05, 2013, 04:31:46 pm
content: QuoteGood advice.

author: BiOzZ
author_rank: Regular Contributor
timestamp: April 05, 2013, 06:12:51 pm
content: damn thats the biggest SD card slot i have seen yet!where do i plug in my ipod?

author: SeanB
author_rank: Super Contributor
timestamp: April 05, 2013, 06:41:19 pm
content: I know that driver's cousin, he works for a courier company..............I always try to pack a parcel so that you can play football with it, or drop it in a scrum ( not American football, a proper Rugby scrum) and have it come out unscathed. Plenty of tape, plenty of packing and strong cardboard. I send lamps that way, and they so far have all arrived intact except for 1 that broke a filament in transit.

author: BobC
author_rank: Unknown
timestamp: April 05, 2013, 07:22:56 pm
content: A Multi-Channel Scaler is fundamentally concerned with measuring pulses: When they arrive, how wide they are, how tall they are, how they are shaped, their total energy, and other parameters. They are typically called "photon counters" because the pulses being analyzed are most commonly from sensors that detect photons, such as photomultiplier tubes or photodiodes.The photons themselves often come from radiation sensors (scintillators mated with photomultiplier tubes), though when non-photonic radiation sensors are used (such as ion chambers), these instruments are then magically called "gamma counters". Other popular photon sources include lidar and many types of fiber optic based sensors.The general field of pulse analysis has many components with overlapping terms and many synonyms and redefinitions: Multi-Channel Analyzer, Pulse-Height Discriminator, Pulse Analyzer, Pulse Dwell Analyzer, and the list goes on and on and on.Fundamentally, we care about several key pulse attributes:Polarity (direction) of leading edgeTime of leading edge detectionRate-of-Rise of leading edgePulse height (peak amplitude)Time of peak heightTime of trailing edge detectionRate-of-Rise (well, fall) of trailing edgePulse widthPulse area (energy)The first and most critical feature of an MCS is clearly to obtain and amplify pulses with extreme linearity and precise timing fidelity: If you look at a narrow tall pulse, its frequency content can be staggering: MCS analog inputs must contain extremely good pulse amplifiers.In any pulse sensor, it is common for more than one sources of pulses to be present. For example, a radiation detector used in medicine (such as in a PET scanner) will also pick up pulses from cosmic rays and natural background radiation, not to mention the X-Ray machine in the next room. So an important feature of an MCS is to "gate" the pulses based on any or all of the above pulse characteristics.Once pulses of interest are identified, what is to be done with them? We count them. But since the pulses of interest will have characteristics that distinguish one from the next, we can choose characteristics of interest to create counting bins, or a histogram. For example, most radiation sensors convert gamma strength to pulse height, so we create bins according to pulse height. A lidar sensor cares more about pulse timing, so we would bin the pulses according to their delay following the initial laser illumination pulse.An important characteristic of many pulse sources, especially radiation detectors, is that the pulse source is inherently random. Pulses may overlap, and there will be arbitrarily long or short delays between pulses. And every pulse detector has a characteristic of its own: It has a "recovery" or "dead" time after detecting a pulse before it is able to detect a subsequent pulse. This is where the "multi-channel" aspect comes in: Multiple pulse detectors are used in parallel, timed to hopefully ensure that at least one is always out of its dead-time, with anti-coincidence logic present to ensure that pulse detectors triggered by the same pulse don't cause that pulse to be counted twice.Even with such precautions, every use of an MCS must be paired with a dead-time analysis, and an ensuing dead-time correction process (a statistical correction). The best MCS units will monitor themselves and provide dead-time alarms (no free pulse detector) and an estimate of the pulses missed due to dead-time effects. Many sensors also exhibit dead times, so the sensor itself must be carefully characterized, and its behavior statistically combined with that of the MCS to determine the overall dead-time penalty.Some SR430 links:http://www.physics.rutgers.edu/ugrad/389/muon/SR430m.pdfhttp://www.thinksrs.com/products/SR430.htmEnjoy!

author: marshallh
author_rank: Unknown
timestamp: April 05, 2013, 07:57:15 pm
content: BobC thanks for your informative post

author: komet
author_rank: Unknown
timestamp: April 05, 2013, 08:21:22 pm
content: In the context of an electronics lab I think it would be useful to measure clock jitter. Apart from that, no idea.

author: EEVblog
author_rank: Unknown
timestamp: April 05, 2013, 10:33:16 pm
content: Quote from: Fezder on April 05, 2013, 02:39:48 pmI cut component pins with the scissors

author: Smokey
author_rank: Super Contributor
timestamp: April 05, 2013, 11:31:27 pm
content: Of all the things to swipe when you leave a company, Dave swipes manuals for test equipment he doesn't haveTell me you at least have a box full of pens and staplers tooThose old manuals do usually have full schematics which are a good source of circuit ideas.

author: EEVblog
author_rank: Unknown
timestamp: April 05, 2013, 11:53:11 pm
content: Quote from: Smokey on April 05, 2013, 11:31:27 pmI bought a ton of stuff when Sercel shut down, but SWMBO found out how much it was all worth and made me sell it all

author: ftransform
author_rank: Frequent Contributor
timestamp: April 06, 2013, 04:47:21 am
content: just in case the fundamental constants change LOL!Did you ever see the movie the quiet earth? Australian film.

author: Fezder
author_rank: Regular Contributor
timestamp: April 06, 2013, 07:27:10 am
content: Quote from: EEVblog on April 05, 2013, 10:33:16 pmhaha, well, its all about personal prefers

author: ninonpas
author_rank: Contributor
timestamp: April 06, 2013, 10:41:59 pm
content: hi dave !you may want a get this from ebay for a next teardown :http://www.ebay.com/itm/NASA-ARTIFACT-VPI-Vehicle-Power-Interface-Rack-Console-Hubble-Space-Telescope-/261090432601i’d buy it myself to convert it into a fancy coffe machine but i don’t have enough room in my kitchen!

author: dexters_lab
author_rank: Unknown
timestamp: April 06, 2013, 11:16:37 pm
content: Quote from: ninonpas on April 06, 2013, 10:41:59 pmNice, but i shudder to think what that cost the american taxpayer!

author: Ferroto
author_rank: Frequent Contributor
timestamp: April 06, 2013, 11:34:16 pm
content: Quote from: ftransform on April 06, 2013, 04:47:21 am

author: G7PSK
author_rank: Super Contributor
timestamp: April 07, 2013, 09:20:56 am
content: Remember the photographs that came in an envelope printed "Photographs Do not bend" and they would come through your letter box doubled over and the postman wrote in pencil on them " Oh yes they do"

author: BobC
author_rank: Unknown
timestamp: April 07, 2013, 06:58:50 pm
content: Quote from: komet on April 05, 2013, 08:21:22 pmWith an MCS at hand, it becomes possible to perform measurements that would otherwise be impractical, generally due to needing an entire bench full of equipment made of unobtanium. You soon develop the mindset of trying to convert almost any signal parameter into an analog pulse train by adding simple circuitry to convert the parameter(s) of interest into pulse characteristics.Let's take your clock-jitter example. Pulse analyzers are very good with short-time events, but less good with longer term events (their clocks are accurate only over relatively short windows). Since jitter is, by definition, the irregular timing of individual edges, we would then want to convert each edge, both positive-going and negative-going, into a pulse. There are many ways to do this, most of them needing less than $5 in parts.The neat thing about working in the pulse domain is that you can get away with some really primitive pulse conversion circuitry, not even caring much about the component values. This is true simply because we tend to care about differences between pulses, the relative measurements, rather than the absolutely correct values.One of the hardest things to do in many analog circuits is to correctly analyze noise in multiple domains (voltage, current, amplitude, phase, harmonics, short-term vs. long-term, etc.). Moving things into the pulse domain can simplify such characterization. I once had to characterize extremely low frequency noise on a 2KV DC power supply: The equipment being fed by the supply was exhibiting long-term semi-periodic irregularities, and every part of the system had to be examined to find the cause. My job was the power supply.The first obvious thing to do was to scale the output voltage down and feed it to a 6-digit DMM. But the DMM itself wasn't stable enough over the long times we were interested in (hours to days). Even the 12-digit meter in our calibration lab wasn't stable enough for long-duration measurements.What I did have access to was a simple voltage-to-frequency converter (VCO), a well-controlled oven, and high-precision voltage reference that WAS stable for days and even years at a time (even inexpensive references are generally more stable and far cheaper than the expensive instruments needed to measure them). I put the VCO into the oven, let it stabilize at a temperature a bit above ambient, fed in my precision voltage reverence, routed the VCO output to a simple pulse converter (also in the oven), and let the MCS run for a few hours. I got a very tall and skinny Gaussian distribution of pulse times that represented the stability of the pulse conversion circuit.I then fed in the supply and took another few hours of data, and got another Gaussian distribution (I used the narrowest timing bins the MCS could provide). The neat thing about Gaussian distributions is that they provide a mathematically simple way to extract meaningful characteristics from huge amounts of data. I first normalized the distributions, then subtracted the reference data from the supply data, and got a distribution that reflected the instability of the supply.For the few hours data I took, the result was barely a wiggly line barely distinguishable from zero. Were a variation present, I would expect the DoG (Difference of Gaussians) to have one or more distinct humps of its own. I repeated the experiment for both the reference and the supply for a full day each, and got nearly the same low-level result: The power supply was not the source of the data variations!The only possibility that I was wrong would require the time-domain instability of the pulse conversion circuitry, the MCS, and even the voltage reference to PRECISELY match that of the supply under test: Not likely at all, unless you include an infinite number of parallel universes, in which case it is certain to occur in one of them. But not in our universe.In today's world of cheap, fast, wide ADCs with almost unlimited sample depth, tricks such as the above are needed less often, and the MCS market has dwindled away accordingly. One unfortunate result is that technicians and engineers have become less familiar with domain conversions in general, especially quick & dirty ones in the lab, as well as the statistical analysis chops needed to make sense of the results.Not that I'm complaining! I did the above while I was a technician at a company that made control systems and instrumentation for commercial and military nuclear power plants. When I went to college, I majored in Computer Engineering (CS + digital parts of EE), and today I make a nice living applying some of those old tricks in the software domain, to make nasty sensors and touchy control systems play nice.A primary key for me has been knowing how to transform between domains: From voltage to frequency, from edges to pulses, from whatever you can't easily measure or analyze, to things you can. To know when you've done the conversion correctly (by creating and performing tests that yield unambiguous results), and to detect when it is no longer correct.That's why I'm an engineer: I get to apply a world of tools to solve nasty puzzles, and I get to do it every day. Learning a new tool, and using it correctly, keeps me jumping out of bed every morning eager to attack my next problem. My favorite problems are the ones that kick my butt and make me feel like an idiot, for I know I will be less of an idiot when I finish!

author: Smokey
author_rank: Super Contributor
timestamp: April 07, 2013, 09:14:03 pm
content: ^^^^^ BobC wins post of the day.

author: BobC
author_rank: Unknown
timestamp: April 08, 2013, 04:29:40 am
content: Quote from: Smokey on April 07, 2013, 09:14:03 pmI should probably share what caused the instability: After exonerating the HVPS, I was asked to compare the problem data behavior to the variations in various environmental parameters: Line voltage, line frequency, humidity, temperature, EMI (electro-magnetic interference), and so on.And wouldn't you know it, the observed variations approximately tracked the daily temperature changes in our test bay. Once I shared this with the engineers, a heat gun and a can of cold spray soon identified the culprit: Our instrument contained a logarithmic amplifier created using a matched Darlington pair in the feedback path of an op-amp. The transistors were precisely matched electrically, but they exhibited thermal effects the initial design had failed to account for. The transistor and op-amp parts were carefully selected to have matching thermal characteristics, but in reality they didn't: Specs lie! Adding a suitable thermistor nicely eliminated the effect, with the thermistor, Darlington pair and op-amp all mounted to a common heat spreader.That logarithmic amp was a true work of art: It was dead-accurate over 6 decades of operation. Then they "improved" it to cover 9 decades, and I was asked to validate the implementation and create the calibration procedure. While the amp was well shielded in normal operation, I had to remove the shields for my tests.When you are operating down at the bottom of 9 decades, you need to measure to 10 or 11 decades, which means measuring quantities that start with "femto" and "atto". I had to enclose my lab bench in a Faraday cage (copper window screen material), and had to avoid using any instruments that emitted significant noise (which included most digital instruments in the early '80's). I had to feed the AC power for my instruments through a 60 Hz resonant isolation transformer to eliminate line noise, and also to get ground isolation (as Dave so brilliantly demonstrated in one of his videos). I did need an extremely low impedance earth reference, so we drilled though the slab near my bench and drove an 11 foot copper-jacketed steel rod into the ground, to which the Faraday cage was connected.This setup was so sensitive that even small arm motions would affect the readings. Including the arm motions needed to write things down. So I would set up a measurement, go to the other end of my lab bench, wait for the setup to stabilize, then use binoculars to read the instruments. Took nearly two weeks just to take the data needed, and a month and a half to get the job done.We didn't quite reach the 9 decade goal, but we did get a rock-solid 8 and a half decades. Left our competitors in the dust: They needed two very expensive systems to measure the range we covered with one. It took them most of a decade to catch up to us. (A "decade", get it? Nudge-nudge, wink-wink.)

author: Fezder
author_rank: Regular Contributor
timestamp: April 08, 2013, 02:42:48 pm
content: woa, nice length for a post! hey, not in negative way.....and all was in sense too.

author: stratogazer
author_rank: Contributor
timestamp: April 08, 2013, 06:10:29 pm
content: Dave,One of the uses for a photon counter is in radiation dosimetry. Certain crystalline compounds absorb radiation. When these crystals are heated they give off photons proportional to the amount of radiation absorbed. The size of the crystal being known, one can calculate the amount of radiation absorbed by the crystal.How ya gonna test it?

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 11, 2013, 04:09:02 pm
content: Quote from: Rufus on April 05, 2013, 03:56:54 pmI actually caught Yodel driver throwing,one of my parcels over the gate, then the very following day City Link did the very same thing, despite seeing me come to the front door to take the very expensive ham radio transceiver off him, however he still threw it over the gate, "TWATS"

author: majki
author_rank: Contributor
timestamp: April 19, 2013, 12:06:19 pm
content: Something related:Hidden camera captures a package's journey from shipment to delivery:http://www.dpreview.com/news/2013/04/18/hidden-camera-captures-packages-journey-from-shipment-to-delivery/printThe camera was controlled by an arduino to record 3 second video every minute and make longer videos while the box was moving.