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8-Cent LM555 Timers - Page 2 — Parallax Forums

8-Cent LM555 Timers

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  • erco wrote: »
    A 555-based robot kit which apparently is of shoddy quality and sullies Banggood's good name. I tried to order one for a shot at robo-redemption but sadly it's sold out.



    Did you manage to grab a schematic?

    I guess it would be easy enough once you get a couple of servos running.
  • kwinnkwinn Posts: 8,697
    erco wrote: »
    A 555-based robot kit which apparently is of shoddy quality and sullies Banggood's good name. I tried to order one for a shot at robo-redemption but sadly it's sold out.


    Aside from the quality I have to wonder how much "educational value" something that simple would have.
  • erco wrote: »


    Ask and you shall recieve, schematic, board layout and parts list. Not sure how much fun this would be, the whole circuit deals with controlling the motors.if all it does is walk, it needs more 555s to blink some lights and make some noise.
  • ercoerco Posts: 20,244
    edited 2016-11-22 21:12
    Fantastic 555 info at http://electronicsclub.info/555timer.htm

    From http://www.555-timer-circuits.com/inside-the-555.html

    Do you notice the three 5k resistors? This is how the chip got it's name.

    inside-the-555-timer.gif
  • erco wrote: »
    Fantastic 555

    Do you notice the three 5k resistors? This is how the chip got it's name.

    inside-the-555-timer.gif



    And sometimes you think its because it sounds catchy.
  • kwinnkwinn Posts: 8,697
    erco wrote: »
    Fantastic 555 info at http://electronicsclub.info/555timer.htm

    From http://www.555-timer-circuits.com/inside-the-555.html

    Do you notice the three 5k resistors? This is how the chip got it's name.

    inside-the-555-timer.gif

    Where did that 555 diagram come from? The upper comparator position and connections look a bit off to me.

    Everyone I have seen looks more like this:
  • ercoerco Posts: 20,244
    40 pcs for $1.76. Pure unadulterated madness at 4.4 cents each.
  • ercoerco Posts: 20,244
    edited 2017-02-08 23:38
    Related, this $1 DIY kit to build a 10-LED "scanner" uses a SMT 555, 4017 and lots of SMT passives. Well worth the dollar just for SMT soldering practice. I built one today. A very high quality PCB. Not my finest soldering job (prolly shoulda cleaned the board with alcohol first) but she worked first time. Wow, I need plenty of light and reading glasses to solder those tiny SMT caps & resistors in place. The 50K trimpot seemed huge & bulky, so I replaced it with a 22K fixed resistor.

    It only scans in one direction, so it's not quite a KITT scanner. It only draws 4 mA powered by a 3.7V LiPo cell. That's so little that you can safely power it directly from a Propeller or Stamp pin to switch it on or off. Ten strobing LEDs is certainly more blingy than a single LED.

    Alternatively, you could leave off the 555 timer (heresy within this thread, I know) and send your pulses directly to the 4017 decade counter clock input to advance the LEDs any way you please.


  • Had to see it built and flashing, this would be a good exercise in SMD.

    Wow if you could get kits that cheep when we were kids. Plus all gratification in lights, that took a lot more to make happen back then.

    I wonder if through hole will be eventually phased out over time.
  • ercoerco Posts: 20,244
    It might actually be cheaper for China to assemble these than pack out this kit. Unless they want us Yanks to kill ourselves off using toxic leaded solder, just for the challenge of mastering SMT!
  • This might be a good kit to buy if you need to screen some lab techs in an interview situation. And you can let them take the kit home when the interview is over, so they don't feel like they've done free labor under the guise of a job interview.
  • ercoerco Posts: 20,244
    KeithE wrote: »
    This might be a good kit to buy if you need to screen some lab techs in an interview situation. And you can let them take the kit home when the interview is over, so they don't feel like they've done free labor under the guise of a job interview.

    Excellent, make it a competition. First guy to complete a working unit gets the job. GO! :)

  • Erco, that Russian assembly video with the Russian mood music was ... different.
  • I got an email today from an electronics company that shall remain nameless. But anybody in this hemisphere into electronics has dealt with them before.

    I had put together a nicer end product back in the 70s. I don't think there is a good side to this example. This type of kit should have it's own special box, even if you have to cut the holes in it. You end up with something pleasant to look at. This doesn't even have red diffused plexiglass, to read the display in sunlight.

    If this is a one board clock kit, mounting options are limited. The people putting the examples out there should pay a little more attention to detail though. This is plain ugly.
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  • That picture is totally photoshopped. The red segments would never look like that in daylight.

    -Phil
  • ercoerco Posts: 20,244
    OK, 4.4 cents for a 555 timer, 10 cents for photocells, so what's our first product guys? Something we can sell for 2000% profit. Nothing but 555s and photocells and other penny items.

    Oppernockety tunes once!
  • MikeDYurMikeDYur Posts: 2,176
    edited 2017-05-28 16:06
    Had to show this little gadget, a sonic mole chaser. And no, I don't think their effective. That's why it only gets Dollar Store D cells.

    But anyway this 555 has been underground for over 15 years, energizing an audible mechanical buzzer, a couple of seconds every 30 seconds or so.

    Still going strong, it may be comforting for the little critters.

    Long live the 555!
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  • ercoerco Posts: 20,244
    Nice 7555. I just built a 555 38 kHz oscillator yesterday for an object detector. Handy little critters.
  • Heater.Heater. Posts: 21,230
    4.4 cents for a 555. Wow!

    I just paid 35 dollars for one:

    2.jpg
  • jmgjmg Posts: 15,140
    Heater. wrote: »
    I just paid 35 dollars for one:
    Looks great, but does it use 5k resistors as mentioned above ?
    If not, then it's not really a '555' is it ? ;)

  • K2K2 Posts: 691
    4.4 cents for a 555 is persuasive. But, from long experience I know that my new design will be finished faster if I use a 60-cent PIC16F54. I'll be happier with the final results, too.

    Maybe it's a lack of cleverness that has me using complicated tools to do simple things. How much more admirable it would be to use simple tools to do complicated things.
  • ercoerco Posts: 20,244
    How much is the matching socket?
  • jmgjmg Posts: 15,140
    K2 wrote: »
    4.4 cents for a 555 is persuasive. But, from long experience I know that my new design will be finished faster if I use a 60-cent PIC16F54. I'll be happier with the final results, too.

    Maybe it's a lack of cleverness that has me using complicated tools to do simple things. How much more admirable it would be to use simple tools to do complicated things.

    Completion costs certainly matter, as do total BOM + Placement costs, and while Digikey has decent stocks of NE555, they are eclipsed by SOT23-6 MCUs, and a total of ~ 30 modest MCUs show more stocks than the highest NE555 hit.
    There are also ~ 30 small MCUs with a 1-off price under 50c

    Asian MCU prices can also be lower, these appear on a recent web update (numbers are F.ram.K.flash.S.uarts), not sure of /volumes ? 10k ?
    STC8F2K32S2-28I-LQFP32, RMB1.8 US$0.26
    STC8F2K60S2-28I-LQFP32, RMB2.0 US$0.29
    STC8F2K64S4-28I-LQFP32, RMB2.8 US$0.41

  • MikeDYurMikeDYur Posts: 2,176
    edited 2017-05-28 23:29
    erco wrote: »
    Nice 7555.

    Honestly only paid attention to the last three numbers. Is this the big brother of 555's? Where did they stop reinventing this wheel, till it could sink a heavy load all by itself. Why not, a timer is a timer, and the less components it takes to do the job the better, right?

    Sometimes I think I'm stuck in TTL land.


    BTW: Heater's example is good for 1500W, by size alone.
  • Heater.Heater. Posts: 21,230
    edited 2017-05-28 23:28
    erco,
    How much is the matching socket?

    Good question.

    I have been wondering how I'm going to make a PCB for this monster 555. Somewhere I have a big sheet of old style phenolic PCB.

    Or perhaps a giant slice of breadboard...

    And how am I going to make 15 times scale resistors and capacitors? (I think I have the LED in hand)
  • jmgjmg Posts: 15,140
    MikeDYur wrote: »
    Honestly only paid attention to the last three numbers. Is this the big brother of 555's? Where did they stop reinventing this wheel, till it could sink a heavy load all by itself. Why not, a timer is a timer, and the less components it takes to do the job the better, right?

    Sometimes I think I'm stuck in TTL land.

    This is the most 'souped up' '555' I know of... the CSS555
    http://www.customsiliconsolutions.com/products-for-ASIC-solutions/standard-IC-products_no.aspx

    you can buy these in low volumes...
    http://www.jameco.com/shop/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=css555&search_type=jamecoall

    but the price is not the 4~8c level ;)

    If you are ok with '555-like', new devices that sit between Logic and MCUs are these from Silego. Very small QFN's, and quite a family there now.

    http://www.silego.com/products/greenpak.html
  • MikeDYurMikeDYur Posts: 2,176
    edited 2017-05-29 01:21
    jmg wrote: »
    If you are ok with '555-like', new devices that sit between Logic and MCUs are these from Silego. Very small QFN's, and quite a family there now.



    I could see that as a culmination of design logic. But what am I supposed to do with this spec of material I have already lost.
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  • K2K2 Posts: 691
    My mind was fairly blown by the Silego GreenPAK programmable mixed-signal chips(!). Didn't know anything about them until now. They are certain to be part of future considerations - they almost demand to be used.
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