Insanely cheap Chinese electronics on Ebay.

Discussion in 'computers, web and general tech' started by gentlegreen, Dec 11, 2016.

  1. gentlegreen

    gentlegreen sproutarian

    I've bought several cheapo amp/volt meters, and I just realised that when you order them with shunts, they're likely to not have the 10 amp shunt soldered to the board.
    I fitted them in a circuit I wasn't expecting to exceed 10 amps, so didn't fit the shunt, and found the load not coming on and with the meter indicating 55 amps.

    I was initially casting aspersions about "value engineering" until it clicked that a 10 amp shunt would significantly impair the accuracy when using a 50 amp shunt.

    :facepalm:

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  2. gentlegreen

    gentlegreen sproutarian

    I couldn't think of anywhere else to fit my mini vice so I've fitted it to my anatomical model.

    I'm likely to use it most for dremelling, so will have to rig up a spark/dust catcher.
    Once I finish the lighting on my magnifier, I will be able to lose the MR16.
    And I've decided that even though solder flux is no more than pine rosin with the high notes removed and I will probably use a wood stove in my dotage, I might as well use up my endless supply of small PC fans to carry the fumes away from my lungs - and coincidentally am able to rotate it and have a small desk fan.

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    Last edited: Jan 12, 2019
  3. gentlegreen

    gentlegreen sproutarian

    And having a bench in the next room with wood-cutting equipment I needed practice on, means I now have more storage (using the plywood back of my parents' 1950s wardrobe to keep the weight down.
    I upgraded the 12 volt supply I use for lighting because I'm already up to the 3.3 amp limit of the old one.
    The ultra-warm Screwfix COB MR16s are so candle-flame warm, I find I still need a decent injection of 4000K for actual work, so am putting the warm whites behind pelmets and adding two adjustable task lights to each bench.

    The "tower of power" in the middle is a one metre high retort stand.

    hobbydesk.jpg
     
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  4. gentlegreen

    gentlegreen sproutarian

    The new second bench featuring the monster "helping-hands" I have yet to actually use in anger ...
    I now have the space to assemble some minimalist test equipment - starting with two linear PSUs based on some very large transformers I have recently acquired and which I am also unlikely to use much in the short term.


    secondbench.jpg
     
  5. gentlegreen

    gentlegreen sproutarian

    My first ESP32 module arrived today.
    Cheaper than most suppliers - perhaps because I had to solder the headers on myself and I thought I was doing OK with a teeny 2mm bit, but next time I will put a foil screen over local sensitive components.
    I suspect it was a plume of my rustic home-made flux that melted a patch of mylar off the OLED flat cable ...

    First day back at work, so somewhat tired ...:rolleyes:

    damage.jpg

    It came with a proper aerial for the LoRa business...

    Getting the libraries into Arduino IDE so I can test it is proving a bother. :p

    I'll need to order at least one more to play with it properly.
     
    Last edited: Jan 14, 2019
  6. gentlegreen

    gentlegreen sproutarian

    And from the same supplier I bought some cheap 2N3055s in old school cans to try and fix the shitty linear PSU kit I assembled a while back - apparently the Chinese used a very old and flawed design.
    I've heard these are quite likely inferior to older versions - they certainly feel a lot lighter... since I have a component tester, I checked them all for gain and base-emitter capacitance - not that I'm seriously going to try using them for RF ...

    2n3055.jpg
     
  7. gentlegreen

    gentlegreen sproutarian

    Found out why my ESP32 LoRa board was cheap - 433MHz - which is the legal band in Asia - though I doubt it would ever be an issue peer to peer.
    In fact, I'm struggling to find any 800MHz devices.

    Embarrassingly I hadn't watched nearly enough Andreas Spiess, so hadn't clicked that it was all about private, community and commercial networks.
    I also hadn't absorbed that the data rate is even slower than morse code !

     
    Last edited: Jan 16, 2019
  8. gentlegreen

    gentlegreen sproutarian

    Bought a new test meter - auto-ranging - £15 - Dave Jones would probably call it rubbish because I couldn't confidently plug it into 600 volts on any range without problems.
    Big Clive is currently using a cheap UNI-T clamp ammeter, but I haven't worked out the model yet so I can order.
    I probably paid £15 for my last one too at Maplin, 15 years ago and the new one has bigger digits, AC current, continuity and several other improvements.

    It arrived at work on Wednesday and I measured my bike light battery at only 12.4 volts, totally failed to get a clue and it let me down on the way home. :facepalm:

    meters.jpg
     
    Last edited: Feb 3, 2019
  9. Saul Goodman

    Saul Goodman It's all good, man Banned

    gentlegreen likes this.
  10. gentlegreen

    gentlegreen sproutarian

    I wish these things had been around when I was being unimpressed by early IBM PC type machines ...
     
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  11. gentlegreen

    gentlegreen sproutarian

    Today's bathtime musings ...

    Minimal involvement of electronics at this point and not very original, but I still have a bicycle wheel device in mind for my future vegetable garden - I suppose electronics would come into play keeping it on track - though I'm clinging to the idea of running a smaller platform in lightweight channels that are moved from row to row.
    Almost certainly electrically powered.

    I will definitely be buying a welder shortly after the pillar drill ...

    1-0_2009.jpg

    culticycle
     
    Last edited: Feb 3, 2019
  12. gentlegreen

    gentlegreen sproutarian

    I thought it was about time to try white LED strip as an ambient lighting source.
    So I paid £7 for 5 metres of "warm white" 5630.
    When I first fired it up, it had the look of older style white LEDs that have a distinct "white with a dob of shite" look, but aimed away from me behind a pelmet, they're quite pleasant.

    warmwhitestrip.jpg

    It's also very effective and efficient illumination, but I'd grown accustomed to the warm-as candlelight MR16s - one at each end, facing outwards, so most of the strip will get used to illuminate my tool and materials shelf units in the room I'm doing up next.

    Difficult to capture in a photo, but it works much better in my bedroom.

    mr16.jpg
     
  13. Saul Goodman

    Saul Goodman It's all good, man Banned

  14. Saul Goodman

    Saul Goodman It's all good, man Banned

    P.S. That bowl could do with a rub of a sandblaster :D
     
    existentialist and gentlegreen like this.
  15. gentlegreen

    gentlegreen sproutarian

    :D
    Now that's a tool I haven't considered for a while. :hmm:
     
  16. Saul Goodman

    Saul Goodman It's all good, man Banned

    I've just 'invested' in a 3d printer :facepalm:
    I've wanted one for years. It had to happen.
     
    gentlegreen likes this.
  17. gentlegreen

    gentlegreen sproutarian

    :cool:

    The trouble with 3D printing is one would need to move on from MS Paint (non-3D) :p

    The more I look at the technology, the more I think I could subvert it - feeding it with melted milk cartons and / or scaling it up to take concrete - or hemp-maché... :D
     
  18. Saul Goodman

    Saul Goodman It's all good, man Banned

    Have you seen the price of them? :eek: It would be wrong not to own one! You can own a decent 3D printer now for less than £200. Everyone should own one... or, knowing me, ten :facepalm:
     
    gentlegreen likes this.
  19. gentlegreen

    gentlegreen sproutarian

    Your first challenge is to print the parts for another 3D printer :)
     
  20. Saul Goodman

    Saul Goodman It's all good, man Banned

    My first challenge is to learn how to program the fucker :D
     
    gentlegreen likes this.
  21. 19sixtysix

    19sixtysix Life as viewed from a Gay Gorbals Garret

    Think of what you want to print, find design already published on line. Easy :)
     
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  22. gentlegreen

    gentlegreen sproutarian

    Bloody hell. Everything will eventually be on the Internet.

    These things were bonkers.

    I had one set up to safely get the sound from a live chassis TV to my amplifier - until I decided to walk up the road with a radio and found I was broadcasting "Charlie's Angels" for a not inconsiderable distance :D
    Josty-Kit HF65.jpg

    hf65.gif

    Willkommen im Selbstbau-Land! - Internet-Radio
     
  23. ViolentPanda

    ViolentPanda Hardly getting over it.

    Got to love analogue meters with chicken-head knobs. :cool:
     
    gentlegreen likes this.
  24. gentlegreen

    gentlegreen sproutarian

    Bloody hell that's cheap !
    I may recommend them to a work colleague who's been asking me if there are cheap LED strips that he could get past his missis...

    I've yet to find a surface the "3M" double-sided tape on the back of cheap LED strips will reliably stick to - so I used several sticks of hot snot in attaching LED strip to my plastic shelf units. (These will, I swear, shortly be highly-efficient storage for my DIY tools and materials :) )

    I've wired them as two separate units so I can fit them back-to back and mount them on some wheeled dollies I have somewhere ...

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    Last edited: Feb 19, 2019 at 2:50 AM
  25. gentlegreen

    gentlegreen sproutarian

    I've been caught out several times by my new battery pack, so I fitted a voltmeter I had lying around. Of course it should be an arduino data logger measuring current and voltage and calculating the total power used during my commutes, but that will have to wait - possibly for ever because if I stick to my original plans, winter 2019/2020 will be my last winter commutes as I will have turned 60 and retired - though who knows, I might get all enthusiastic about night time recreational cycling if I manage to pull off the move to Brittany ...

    Lovely big digits - very much inspiring me to come up with a speedometer / mileometer with genuinely large digits.

    Hot snot FTW :D

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    Last edited: Feb 19, 2019 at 2:51 AM
  26. dervish

    dervish if you flibble when you wibble, don't wobble

    I've bought a couple of these 35CM 52CM 5W 8W 2835 SMD USB Dimmable LED Rigid Strip Bar Light Eyes Reading Table Lamp DC5V they were exactly what I needed, small, bright, dimmable, usb powered and the ability to change the light colour from blueish to orangeish. they were so good I bought another one, then after moving the kitchen around I decided that I needed another one, they are now out of stock. :(
    I'm waiting for more.
     
  27. gentlegreen

    gentlegreen sproutarian

    Have you tried pasting the description into ebay ?
    Always a gamble though - certainly more expensive.
     
  28. gentlegreen

    gentlegreen sproutarian


    :D
     

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